Only a handful of places left for our September 2026 cohort. Applications close soonApply now →

MSTA
Your future
starts here.

Cryotherapy (Skin)

Also known as: cryo, cryotherapy, cold therapy

Controlled destruction of skin tissue by freezing. A cryogen — usually liquid nitrogen or pressurised nitrous oxide — cools tissue until ice forms inside and around cells, killing them by mechanical rupture, osmotic injury and vascular stasis. It destroys tissue; it does not diagnose it.

Evidence status

Moderate

For clinician-diagnosed actinic keratoses, cryosurgery is guideline-backed and prospective clearance reached 67.2%, rising with freeze duration; evidence is weaker for viral warts and seborrhoeic keratoses. The evidence base does not establish professional skin-tag treatment or quantify pigment-loss risk by Fitzpatrick phototype, and cryotherapy destroys the specimen that histology would otherwise examine. A prominent recent review was funded by a cryogen supplier, while manufacturer claims of no infection risk, no aftercare or lesion treatment without referral are unsupported.

What skin cryotherapy is, and the types available#

Skin cryotherapy—also called cryosurgery or cryocautery—is controlled destruction of a small area of tissue by freezing. Liquid nitrogen and pressurised nitrous oxide are common cryogens; contact probes and spray systems create different ice geometry. The procedure destroys tissue but does not identify what that tissue is.

It is distinct from cryolipolysis, which cools subcutaneous fat for body contouring, and whole-body cryotherapy, which exposes the body to very cold dry air for a short recovery treatment. Scottish law defines lesion cryotherapy and cryolipolysis separately.[8, 14] Whole-body cryotherapy evidence concerns muscle soreness rather than lesion destruction: Cochrane found four small trials involving 64 mainly male participants, with very low-quality evidence and no active adverse-event surveillance.[13]

Cryotherapy is also different from curettage or excision because it leaves no specimen. A freeze produces an inflammatory wound and later scab; tissue removed by curettage or excision can be sent for histology.[5, 6]i

Use of skin cryotherapy in aesthetic practice#

There is no UK-wide practitioner licence or qualification for lesion cryotherapy, and no JCCP benchmark competence standard. JCCP's adjunctive/orphan-treatment guidance supplies general scope and premises duties but does not name or standardise cryotherapy.[20]

Scotland has a specific route. Its 2026 licensing order defines cryotherapy or cryocautery as applying cold liquid, gas or an instrument to destroy skin cells in a small area for removal or reduction of lesions or blemishes. A local-authority licence will be required, but article 4(2) means no licence is needed before 6 September 2027. The order expressly includes moles within “skin lesions or blemishes”. That makes moles legally within the licensable description, not clinically suitable for destruction without diagnosis.[8][8]

Plain lesion cryotherapy is not in Schedule 1 of Scotland's separate 2026 Non-surgical Procedures Act and is captured there only when performed with a prescription-only anaesthetic or on an intimate area.[9, 8]

England's 2023 consultation proposed cryotherapy/cryocautery for lesion removal as amber, with oversight by a named regulated healthcare professional for non-healthcare practitioners. No scheme is in force, and the 2025 response did not settle individual tiers. Wales' special-procedures scheme does not include cryotherapy. The position in Northern Ireland is not established by the cited sources and requires a separate local check.[22, 23][24]

Cryosurgical devices placed on the GB market are medical devices under the UK Medical Devices Regulations 2002, with MHRA oversight and the applicable conformity marking. A US FDA clearance has no UK legal effect.[19, 17]

Contraindications and cautions#

The decisive contraindication is diagnostic uncertainty. A pigmented, changing, irregular, bleeding, ulcerated, recurrent or otherwise atypical lesion is assessed before any destructive procedure. NICE requires suspected-cancer referral for a suspicious pigmented lesion scoring three or more on the weighted seven-point checklist or where dermoscopy suggests melanoma.[7, 6]

Melanoma can mimic seborrhoeic keratosis. Among 9,204 specimens submitted with a clinical diagnosis including seborrhoeic keratosis, 61 (0.66%) were melanoma; in three, seborrhoeic keratosis was the only clinical diagnosis recorded.[6] Even actinic keratosis can be difficult to distinguish from superficial basal-cell carcinoma, squamous-cell carcinoma in situ, invasive squamous-cell carcinoma or amelanotic melanoma, for which UK guidance notes biopsy or excision may be needed.[3]

Pigment risk is also intrinsic. Melanocytes are damaged at temperatures far warmer than those used to ablate many lesions, so the freeze front crosses a pigment-damaging isotherm around the target.[10, 12, 17] Deeply pigmented skin makes the resulting contrast more visible, while no study has quantified incidence by Fitzpatrick phototype.

Impaired healing, active infection, compromised circulation or sensation, a history of abnormal scarring and sites where nerve, tendon or eye injury is plausible require device-specific assessment or medical referral. The current IFU and responsible clinician's diagnosis govern; Skinipedia does not publish a freeze-time protocol.

Clinical uses and the evidence behind them#

Actinic keratosis

UK guidance gives cryosurgery strength-A, level-1++ support as a first-line lesion-directed treatment for diagnosed actinic keratosis, while warning that larger doses increase pigment loss and scarring. This is a medical premalignant diagnosis, not a licence for an aesthetic practitioner to diagnose or destroy a rough lesion.[3]

In a prospective study of 421 actinic keratoses in 90 patients, complete response was 39% with freezes under five seconds, 69% over five seconds and 83% over 20 seconds; overall complete response was 67.2%. The authors called that significantly lower than previously reported while still concluding that cryosurgery was effective with generally mild, tolerated adverse events. The figures show technique dependence; they are not a generic treatment schedule.[4, 3]

That study was a subsidiary of a photodynamic-therapy trial with a substantially overlapping author group. Its own funding statement was unavailable, while the companion trial evaluated a commercial methyl-aminolevulinate product; commercial sponsorship cannot be excluded.[4]

Viral warts and verrucae

Cochrane's review of 85 trials and 8,815 participants found no significant advantage over placebo (RR 1.45, 95% CI 0.65–3.23) or salicylic acid (RR 1.23, 95% CI 0.88–1.71). One trial favoured cryotherapy over both only for hand warts.[1]

Combination salicylic acid plus cryotherapy modestly outperformed salicylic acid alone (RR 1.24, 95% CI 1.07–1.43; two trials, 328 participants). Aggressive freezing outperformed gentle freezing (RR 1.90, 95% CI 1.15–3.15) but increased adverse effects; varying intervals of two, three or four weeks did not significantly change cure. These are review findings, not a Skinipedia protocol.[1][1]

A UK randomised trial of 240 NHS podiatry and primary-care patients found 14% complete plantar-wart clearance at 12 weeks in both cryotherapy and 50% salicylic-acid arms (difference 0.65%, 95% CI −8.33 to 9.63; p=0.89).[2]

Seborrhoeic keratoses

In a prospective comparison of 123 lesions, clearance was 50% with cryotherapy, 55% with 532 nm laser and 87.5% with curettage (p<0.01 across groups). The authors called cryotherapy comparable with laser but with more adverse events and a cost-effective alternative. Curettage—not laser—was clearly superior and also produced tissue for histology.[5]

Skin tags and malignant lesions

No professional clinic-based randomised evidence establishes efficacy for skin-tag cryotherapy; the available randomised comparison tested two manufacturer-funded home-use pens without a sham or untreated control.

Cryotherapy evidence for lentigo maligna or melanoma in situ comes from case series. A Cochrane review searched eight databases and five trial registries and found one eligible randomised trial, which did not test cryosurgery. These diagnoses remain specialist care.[15, 10]

The 2025 review used here for much of the cryobiology and indication synthesis was funded by Air Products PLC, an industrial-gas supplier of cryogens, and included an Air Products employee as a co-author, while declaring no conflicts of interest. Its commercial provenance travels with the review's conclusions.[10]

Selecting lesion cryotherapy#

Selection starts with diagnosis, because destructive treatment removes the opportunity for histology. A lesion's appearance, site, recurrence, pigmentation and change history determine whether destruction is even a valid option.[3, 5, 6, 7]

The cryogen, delivery system and ice geometry are not interchangeable. Cryobiology describes tissue response as depending on minimum temperature, cooling and thaw behaviour and repeated freeze–thaw exposure.[10, 12] That evidence explains why outcome is operator- and device-dependent; it does not provide a safe generic spray time or cycle count.

Keratin is a poor heat conductor, so hyperkeratosis can insulate the lesion base. Review literature advocates debulking or paring, and Cochrane subgroup results suggested but did not prove better outcomes on hands than feet. Whether skin penetration or debulking sits within practitioner scope must be resolved before selecting treatment, not improvised at the appointment.[10, 1]i

The current device IFU, verified diagnostic competence, insurer and local law govern cryogen, distance, exposure, repeat cycle, treatment interval and wound care.

Adverse effects and their management#

Expected wound response

Pain, erythema, oedema, blistering, exudation, crusting and later scab formation follow tissue freezing. These are consequences of controlled necrosis, not proof that the lesion was correctly diagnosed or completely treated.

Pigment change

In a standardised human freeze-injury study, every lesion developed hypopigmentation with a peripheral hyperpigmented rim, persisting for at least six months. After brief freezes, pallor persisted even though functional melanocytes remained. Hypopigmentation therefore does not always mean melanocytes are absent, and pigment recovery cannot be predicted from colour alone.[11]

The pigment-loss mechanism is expected rather than necessarily a technique error. Deeply pigmented skin bears a greater visible consequence, but no phototype-specific incidence or permanence estimate exists.[17, 10]

Scarring, nerve injury and infection

More destructive freezing increases clearance and adverse effects.[1, 3, 4] Prolonged healing, infection, ulceration, hypertrophic scarring, sensory change and damage to deeper structures require medical assessment. A lesion that recurs or fails to behave as expected must be diagnosed rather than repeatedly frozen.

Diagnostic harm

The most consequential adverse outcome is delay in diagnosing malignancy. Cryotherapy leaves no specimen, and clinically benign-appearing lesions can prove malignant.[5, 6, 7] Consent cannot repair a scope failure where diagnosis was not competent.

Referral and scope boundaries#

Any changing, irregular, asymmetrical, variably pigmented, bleeding, ulcerated or recurrent lesion, or one meeting NICE's weighted seven-point or dermoscopic melanoma criteria, requires the suspected-cancer pathway rather than destruction.[7]

Actinic keratosis is a medical diagnosis with a differential that includes in-situ and invasive cancers.[3] Basal-cell carcinoma, squamous-cell carcinoma, melanoma, lentigo maligna and uncertain lesions belong to appropriately qualified medical care. Vendor claims that non-recurrent basal-cell carcinoma can be treated without referral conflict with NICE referral guidance.[17, 18, 7]

Warts with an uncertain diagnosis, immunosuppression, atypical site, bleeding or failure of appropriate treatment require clinical review. Post-treatment infection, deep ulceration, persistent neurological symptoms or abnormal healing also requires referral.

Mechanism of action#

Extracellular ice draws water from cells and concentrates solutes, disrupting membranes and enzymes. Faster cooling nearer the applicator traps water inside cells, allowing intracellular ice to rupture organelles and membranes. Ice spreading along vessels damages endothelium and produces thrombosis, ischaemia and later coagulation necrosis.[10, 12]

Different cell types have different thresholds. Reviews place benign-cell ablation around −20°C and resilient malignant cells around −40 to −50°C, while melanocyte damage is reported below approximately −5°C. The −50°C neoplastic figure comes from Gage and Baust; the melanocyte threshold rests on a narrative review because the cited primary paper was not retrieved.[10, 12]

Classic cryobiology describes rapid freezing, slow thawing and repeat freeze–thaw as more destructive. These are mechanistic relationships, not a treatment-room protocol; optimal duration for many benign lesions remains unknown.[12, 10]

The most comprehensive recent cutaneous-cryosurgery review was funded by cryogen supplier Air Products PLC and included an Air Products employee as co-author while declaring no conflict. Its mechanistic synthesis remains useful, but its commercial context travels with it.[10]

Commonly misstated claims#

“Cryotherapy is a proven standard treatment for every wart.”

Cochrane found no significant benefit over placebo or salicylic acid overall, and the UK verruca trial found 14% clearance in both arms.[1, 2]

Supported statement: cryotherapy remains a commonly used wart treatment, with modest and site-dependent evidence and no clear overall superiority to salicylic acid.

“Cryotherapy is simple and technique-independent.”

Actinic-keratosis clearance ranged from 39% to 83% with freeze duration, while more aggressive wart freezing improved clearance and adverse effects together.[1, 4]

Supported statement: outcome and harm depend materially on exposure, tissue and device; manufacturer instructions and competence are central.

“If a lesion looks benign, it is safe to freeze.”

Among 9,204 specimens clinically labelled to include seborrhoeic keratosis, 61 were melanoma and three had no alternative diagnosis recorded.[6]

Supported statement: diagnosis precedes destruction; uncertain or pigmented lesions require dermoscopic or medical assessment.

“Hypopigmentation means all melanocytes were destroyed.”

Human freeze injury produced persistent pallor even after brief exposure where functional melanocytes remained.[11]

Supported statement: pigment change is an inherent and potentially prolonged cryotherapy effect, and visible pallor does not reveal the melanocyte count.

Areas of remaining uncertainty#

  • Optimal exposure and cycle number for benign lesions; without lesion-specific data, a universal freeze protocol would be unsafe.
  • The precise melanocyte injury threshold; accessible literature agrees on high cold sensitivity but not a securely sourced number.
  • Hypopigmentation incidence and permanence by Fitzpatrick phototype; without stratified data, consent cannot quote a reliable percentage.[no source found]
  • Adverse outcomes in UK non-medical practice; without a registry or denominator, complication rates are unknown.
  • England's eventual tier and oversight model; until regulations are made, the amber proposal must not be described as law.

Frequently asked questions#

Is cryotherapy effective for verrucae?

In a 240-person UK trial, cryotherapy and 50% salicylic acid each cleared 14% at 12 weeks.[2]

Can a skin tag or mole be frozen without diagnosis?

No destructive treatment should proceed where lesion identity is uncertain. Moles and atypical pigmented lesions require competent assessment, and suspicious lesions follow NICE referral.[6, 7]

Is pigment loss avoidable?

It cannot be treated as wholly avoidable because melanocytes are intrinsically cold-sensitive. Its incidence by phototype has not been quantified.[10, 11, 17]i

Is skin cryotherapy the same as fat freezing?

No. Cryolipolysis targets subcutaneous fat for contouring and has a different risk profile, including paradoxical adipose hyperplasia.[8, 14]

What freeze time and aftercare should be used?

The exact device IFU and clinician-led lesion plan govern. Skinipedia does not provide a generic freeze duration, cycle count, interval or wound-care protocol.

References#

Each source is graded by evidence tier. Tier 4 material (manufacturer documents, expert consensus, practitioner experience) is useful for protocol and context, and is never presented as equivalent to independent clinical evidence.

  1. Kwok CS, Gibbs S, Bennett C, Holland R, Abbott R. Topical treatments for cutaneous warts. Cochrane Database of Systematic Reviews 2012;9:CD001781. DOI: 10.1002/14651858.CD001781.pub3. PMID 22972052.Tier 1Supports: 85 randomised trials, 8,815 randomised participants, non-genital cutaneous warts in healthy immunocompetent adults and children; searches to May 2011. Cryotherapy versus placebo at all sites favoured neither intervention nor control: RR 1.45, 95% CI 0.65 to 3.23. Subgroups: hands RR 2.63 (95% CI 0.43 to 15.94), feet RR 0.90 (95% CI 0.26 to 3.07) - the reviewers note these 'suggested better outcomes for hands than feet', though neither subgroup estimate reached significance. Cryotherapy versus salicylic acid at all sites: RR 1.23, 95% CI 0.88 to 1.71 (no significant difference). IN CRYOTHERAPY'S FAVOUR, and reported here so the negative is not overstated: 'One trial showed cryotherapy to be better than both placebo and SA, but only for hand warts'; salicylic acid plus cryotherapy versus salicylic acid alone RR 1.24, 95% CI 1.07 to 1.43 (2 trials, 328 participants); and aggressive versus gentle cryotherapy RR 1.90, 95% CI 1.15 to 3.15, 'but with increased adverse effects'. For context on the comparator, salicylic acid versus placebo was significant at all sites (RR 1.56, 95% CI 1.20 to 2.03). 'There was no significant difference in cure rates between cryotherapy at 2-, 3-, and 4-weekly intervals.' Authors' conclusion, verbatim: 'The evidence remains more consistent for SA, but only shows a modest therapeutic effect... Adverse effects, such as pain, blistering, and scarring, were not consistently reported but are probably more common with cryotherapy.' Scope limits: non-genital warts only, immunocompetent patients only, many included studies judged at high risk of bias, evidence base closes at 2011.Funding / interest: PubMed record carries the statement: 'Conflict of interest statement: None declared.'
  2. Cockayne S, Hewitt C, Hicks K, et al.; EVerT Team. Cryotherapy versus salicylic acid for the treatment of plantar warts (verrucae): a randomised controlled trial. BMJ 2011;342:d3271. PMID 21652750.Tier 2Supports: Multicentre, open, two-arm RCT; 240 patients aged 12 and over with a plantar wart, recruited in university podiatry school clinics, NHS podiatry clinics and primary care in England, Scotland and Ireland. Cryotherapy with liquid nitrogen delivered by a healthcare professional, up to four treatments two to three weeks apart, versus patient self-treatment with 50% salicylic acid (Verrugon) daily for up to eight weeks. Primary outcome, complete clearance of all plantar warts at 12 weeks: salicylic acid 17/119 (14%) versus cryotherapy 15/110 (14%); difference 0.65%, 95% CI -8.33 to 9.63, P=0.89. Self-reported clearance at six months: 29/95 (31%) versus 33/98 (34%); difference -3.15%, 95% CI -16.31 to 10.02, P=0.64. Time to clearance HR 0.80, 95% CI 0.51 to 1.25, P=0.33. Conclusion: 'Salicylic acid and the cryotherapy were equally effective for clearance of plantar warts.' Scope limits: plantar warts only; open-label; both arms cleared few warts, so this is equivalence at a low absolute success rate, not evidence that either works well.Funding / interest: Health Technology Assessment (NIHR) grant funded proportions of nine authors' salaries. Authors declared no financial relationships with organisations that might have an interest in the submitted work.
  3. de Berker D, McGregor JM, Mohd Mustapa MF, Exton LS, Hughes BR. British Association of Dermatologists' guidelines for the care of patients with actinic keratosis 2017. British Journal of Dermatology 2017;176(1):20-43. PMID 28098380.Tier 1Supports: UK national guideline. Grades cryosurgery for actinic keratosis at 'strength of recommendation A, level of evidence 1++' - the highest grade in the scheme. Reports the freeze-duration gradient verbatim, WITH its own site qualifier: 'A duration < 5 s showed 39% cure, 5-20 s, 69% cure and > 20 s, 83% cure on the scalp and face.' Warns: 'With larger doses it is likely to result in loss of pigment and scarring.' On diagnosis: 'Diagnosis is typically on clinical grounds. Uncertainty may arise in distinguishing AKs from superficial BCC, SCC in situ, invasive SCC and even amelanotic melanoma, where a skin biopsy or excision for histological examination may be indicated.' On setting: 'Most AKs can be diagnosed and treated in primary care,' with referral where AK fails standard treatment or where lesions might be SCC. Scope limits: actinic keratosis only; assumes a clinician competent to make the diagnosis and to recognise the malignant differentials; the freeze-duration figures are for scalp and face; published 2017 and not updated since as at August 2026.
  4. Thai KE, Fergin P, Freeman M, et al. A prospective study of the use of cryosurgery for the treatment of actinic keratoses. International Journal of Dermatology 2004;43(9):687-692. PMID 15357755.Tier 3Supports: Prospective, multicentre study, run as a subsidiary of a photodynamic therapy trial. 90 adult community patients with 421 eligible untreated actinic keratoses greater than 5 mm on face and scalp. Single freeze-thaw cycle of liquid nitrogen by spray device; each centre used its own preferred freeze time; the only treatment criterion was complete freezing of the AK plus a 1 mm rim of normal skin. Reviewed at 3 months. Overall individual complete response 67.2% (SEM +/-3.5%; 95% CI 60.4-74.1%). By freeze time: 39% complete response for under 5 s, 69% for over 5 s, 83% for over 20 s. Cosmetic outcomes good to excellent in 94% of complete-response lesions. 'The main adverse events were pain, stinging, and burning during treatment, and hypopigmentation after healing.' The authors' conclusions are BOTH positive and deflationary and both are reported here: 'Cryosurgery is an effective treatment for actinic keratoses. The true complete response rate is significantly lower than that previously reported. The freeze duration influences successful treatment. Adverse events are mild and well tolerated.' Scope limits: face and scalp AKs over 5 mm only; single freeze-thaw cycle; no control arm; dermatologist operators, so results are an upper bound for less experienced hands.Funding / interest: No funding statement is recorded in the PubMed entry and the full text could not be retrieved. The study is described by its own authors as 'a subsidiary study of a photodynamic therapy trial'; the companion PDT trial was verified as Freeman M, Vinciullo C, Francis D, et al. J Dermatolog Treat 2003;14(2):99-106 (PMID 12775317), which evaluated methyl aminolevulinate (Metvix), a commercial product, and shares eleven authors with Thai 2004 - so a commercial sponsor for the parent trial should be assumed rather than excluded. For what it is worth, that parent trial independently reported a 68% lesion response rate in its single-freeze-thaw-cycle cryotherapy arm, closely matching Thai's 67.2%.
  5. Timmermann V, Krengel S, Mrowka P, Haase O. Practical Approaches for Seborrheic Keratosis Treatment: Curettage Versus 532-nm Lithium Borate Laser Versus Cryotherapy: A Prospective Interventional Study. Lasers in Surgery and Medicine 2025;57(7):581-589. PMID 40619638.Tier 3Supports: Prospective interventional study, German dermatology group practice. 30 subjects, 123 seborrhoeic keratoses, randomised allocation between curettage, 532 nm laser and propane-butane cryotherapy; assessment at 0, 4, 8 and 12 weeks; blinded cosmetic rating by 125 observers. Clearance: curettage 87.5%, laser 55%, cryotherapy 50% (p<0.01). Observers rated curettage cosmetically superior (50% versus laser 22.5%). Patients perceived complete healing least often after cryotherapy (53%, versus laser 90% and curettage 87%). Pain VAS: laser 4.62, cryotherapy 3.85. The authors' own framing of cryotherapy is NOT uniformly negative and is reported here in full: 'Cryotherapy showed efficacy comparable to laser (50% vs. 55%) but more adverse events', and 'Propane-butane cryotherapy offers a cost-effective alternative.' Authors' conclusion: 'Curettage remains optimal for thick, hyperkeratotic SKs, enabling histopathological confirmation.' Scope limits: small (30 subjects), single centre, 12-week follow-up, propane-butane cryogen rather than liquid nitrogen, Fitzpatrick phototypes not reported; the 50% versus 55% difference between cryotherapy and laser was not presented as significant.Funding / interest: No conflict-of-interest or funding statement is recorded in the PubMed entry; the publisher full text could not be retrieved to check. Treat the commercial disclosure as unverified rather than absent.
  6. Izikson L, Sober AJ, Mihm MC Jr, Zembowicz A. Prevalence of melanoma clinically resembling seborrheic keratosis: analysis of 9204 cases. Archives of Dermatology 2002;138(12):1562-1566. PMID 12472343.Tier 3Supports: Retrospective review of 9,204 consecutive pathology reports from 1992-2001 at a tertiary dermatopathology laboratory, all containing a clinical diagnosis of seborrhoeic keratosis or a differential including it. Melanoma was the final histological diagnosis in 61 cases (0.66%). Melanoma was in the stated clinical differential in only 31 of those 61 (51%); in 17 (28%) the differential was seborrhoeic keratosis versus melanocytic naevus, in 7 (12%) basal cell carcinoma, in 3 (5%) a squamous proliferation, and 'In 3 cases (5%), seborrheic keratosis was the only clinical diagnosis.' All histological types of melanoma were represented. Authors' conclusion: 'These data strongly support the current policy of submitting for histological examination all specimens that have been removed from patients.' Scope limits: 2002, single tertiary centre with a busy pigmented-lesion clinic (a referral population enriched for difficult lesions, so the 0.66% is not a community-clinic rate); lesions were excised by dermatologists, so this understates the risk when the clinician is less trained.Funding / interest: No funding or conflict statement is recorded in the PubMed entry.
  7. National Institute for Health and Care Excellence. Suspected cancer: recognition and referral. NICE guideline NG12, section 1.7 Skin cancers. Published 23 June 2015, last updated 15 April 2026.Tier 1Supports: England-wide referral guideline; page confirmed as published 23 June 2015, last updated 15 April 2026. Recommendation 1.7.1: 'Refer people using a suspected cancer pathway referral for melanoma if they have a suspicious pigmented skin lesion with a weighted 7-point checklist score of 3 or more.' Weighted 7-point checklist: major features scoring 2 points each - change in size, irregular shape, irregular colour; minor features scoring 1 point each - largest diameter 7 mm or more, inflammation, oozing, change in sensation. 1.7.2: refer if dermoscopy suggests melanoma of the skin. 1.7.3: consider referral for a pigmented or non-pigmented lesion that suggests nodular melanoma. 1.7.4: consider suspected cancer pathway referral where a lesion raises the suspicion of squamous cell carcinoma. 1.7.5: consider NON-URGENT referral for suspected basal cell carcinoma ('an ulcer with a raised rolled edge; prominent fine blood vessels around a lesion; or a nodule on the skin [particularly pearly or waxy nodules]'), with 1.7.6 reserving the urgent pathway for cases where delay would have significant impact because of factors such as lesion site or size. Scope limits: written for NHS clinicians deciding on referral, not for aesthetic practitioners; it says nothing about destroying lesions, because the guideline assumes lesions of concern are referred, not treated.
  8. The Civic Government (Scotland) Act 1982 (Licensing of Non-surgical Procedures) Order 2026, SSI 2026/87. Made 12 February 2026; in force 13 February 2026.Tier 1Supports: Scottish secondary legislation designating specified non-surgical procedures as activities requiring a civic licence under Part 1 of the Civic Government (Scotland) Act 1982. Schedule 1 paragraph 3 defines the procedure verbatim: 'Cryotherapy (or cryocautery) — A procedure in which a cold liquid, gas or instrument is applied to destroy skin cells in a small and specific area of the body for the purpose of removing or reducing skin lesions or blemishes.' Schedule 1 paragraph 2 separately defines cryolipolysis: 'A procedure in which a device is used to reduce the temperature of a specific part of the body to destroy fat cells for the purpose of reducing fat deposits.' Schedule 1 paragraph 9 (interpretation): 'references to "skin lesions or blemishes" include acne, blisters, cysts, freckles, moles, skin tags, scarring, rashes and warts.' Article 4(2): 'a licence is not required in respect of the carrying on of that activity before 6 September 2027.' Article 3(1)(b) excludes procedures using a prescribed anaesthetic, procedures on intimate areas, procedures provided by or on behalf of NHS Scotland, procedures provided by a health care provider for preventing, diagnosing or treating an illness, and procedures in 'excepted premises' (HIS-registered independent hospitals and qualifying clinics, GP and dental premises, registered pharmacies). Scope limits: Scotland only; premises/activity licensing by local authority, not a competence standard; whole-body cryotherapy is not among the eight specified procedures.
  9. Non-surgical Procedures and Functions of Medical Reviewers (Scotland) Act 2026 (2026 asp 13). Passed 17 March 2026; Royal Assent 12 May 2026. Commencement by SSI 2026/206.Tier 1Supports: Act of the Scottish Parliament prohibiting provision of specified non-surgical procedures to under-18s and outside 'permitted premises', with powers for Scottish Ministers to impose further restrictions, entry and seizure powers, criminal penalties and statutory guidance. Passed 17 March 2026, Royal Assent 12 May 2026 (both confirmed on the enacted text). Schedule 1 specifies TEN procedures, set out across numbered paragraphs 1 to 11 (paragraph 9 is not a procedure - it is an exclusion carved out of the microneedling entry at paragraph 8): ablative laser treatment; chemical peel penetrating deeper than the epidermis; dermal microcoring; injectable procedure; intravenous procedure; a licensed procedure carried out with a prescribed anaesthetic; a licensed procedure carried out on an intimate area (other than non-ablative laser hair removal); microneedling (any depth if delivering radiofrequency, otherwise 1.5 mm or more); subcision; thread lift. Plain lesion cryotherapy is NOT in Schedule 1: it is caught by the Act only via paragraph 6 (a procedure specified in schedule 1 of SSI 2026/87 for which a prescribed anaesthetic is used) or paragraph 7 (such a procedure carried out on an intimate area). Scope limits: Scotland only; the Act is being commenced in phases via SSI 2026/206 (C. 21), which appoints 22 July 2026 for the provisions in its Schedule, and is not fully in force.
  10. Mokbel R, Kodresko A, Mokbel K, Ghazal H, Trembley J, Jouhara H. Cutaneous Cryosurgery in Dermatology: Evolving Principles and Clinical Applications for Benign, Premalignant, and Malignant Lesions. In Vivo 2025;39(2):577-612.Tier 4Supports: Narrative review, not systematic; no search strategy, no risk-of-bias assessment, no quantitative synthesis. Mechanism statements used here, verbatim: 'Benign cells are typically ablated at -20˚C, while more resilient cancerous cells require a target temperature of -40˚C to -50˚C. Melanocytes, which produce melanin, are highly sensitive to thermal changes and are damaged at temperatures below -5˚C.' On technique: 'The basic cryosurgery technique consists of rapidly freezing target tissue to a lethal temperature, followed by a relatively slow thaw, and repeating the freeze-thaw cycle... A slow thaw rate within the -20˚C to -25˚C range is particularly advantageous, as it encourages the growth of ice crystals, enhancing tissue damage through microvascular failure and stasis... Ideally, repetition should occur between -20˚C and -30˚C.' On vascular injury: ice crystals propagate along the vascular system, damaging endothelium and basement membrane, producing 'thrombus formation and ischemia', increased vascular permeability, oedema, neutrophil and macrophage influx, 'culminates with a zone of coagulation necrosis'. On conduction: 'Keratin... also conducts poorly, thus debulking hyperkeratotic lesions before cryosurgery is advisable.' On darker skin: intralesional technique 'provided a friendly surface thermal history that is crucial for the melanocytes... and therefore fewer hypopigmentation, which is of special importance in black or darker-colored skin patients.' The review's own closing caveat: 'available research remains limited, often relying on older, short-term findings from single-case reports.' Scope limits: this is the single most comprehensive recent overview but it is promotional in tone, advocates cryosurgery for primary cutaneous melanoma stages II-IV and for lentigo maligna on the strength of case series, and cites no controlled trials for those indications.Funding / interest: COMMERCIAL INTEREST. Stated funding: 'The reported work was supported by Air Products PLC under grant agreement: 216-206-P-F. Grant Holder: Professor Hussam Jouhara.' Air Products PLC is an industrial gas company and a supplier of cryogens. Co-author Jon Trembley is affiliated to 'Air Products PLC, Hersham Place Technology Park, Surrey, U.K.' Despite this, the paper states: 'The Authors declare no conflicts of interest in relation to this study.' Two further co-authors (R Mokbel, K Mokbel) are affiliated to a private hospital group (Princess Grace Hospital, HCA Healthcare UK).
  11. Burge SM, Bristol M, Millard PR, Dawber RP. Pigment changes in human skin after cryotherapy. Cryobiology 1986;23(5):422-432. PMID 3769517.Tier 3Supports: Human in-vivo study of pigmentation and melanocyte distribution after a standardised freeze injury, with histology. Findings verbatim: 'All lesions developed hypopigmentation with a peripheral rim of hyperpigmentation. Abnormalities in pigmentation persisted for at least 6 months. Hyperpigmentation was predominantly an epidermal phenomenon. After brief freezes, hypopigmentation persisted despite the presence of functional melanocytes. After prolonged freezes, the consistent finding was an absence of melanosomes in keratinocytes, although melanocytes were present.' Authors' conclusion: 'prolonged changes in skin color are frequent after brief freezes and that hypopigmentation is not synonymous with an absence of melanocytes. This suggests that hypopigmentation after the cryosurgical treatment of malignant melanocytic tumors may not equate with cure.' Scope limits: small experimental study in human volunteers, 1986; the abstract does not state sample size or the phototypes studied, and the full text is paywalled, so the population could not be characterised further. The load-bearing point - that even a brief freeze produces pigment change lasting six months or more - is stated directly by the authors.
  12. Gage AA, Baust J. Mechanisms of tissue injury in cryosurgery. Cryobiology 1998;37(3):171-186. PMID 9787063.Tier 4Supports: Authoritative narrative review of cryobiological mechanism by the two figures who defined the modern technique; no pooled data. Key statements verbatim: 'the basic features of cryosurgical technique were established as rapid freezing, slow thawing, and repetition of the freeze-thaw cycle'; 'The cooling rate should be as fast as possible, but it is not as critical as other factors. The coldest tissue temperature is the prime factor in cell death and this should be -50 degreesC in neoplastic tissue. The optimal duration of freezing is not known, but prolonged freezing increases tissue destruction. The thawing rate is a prime destructive factor and it should be as slow as possible. Repetition of the freeze-thaw cycle is well known to be an important factor in effective therapy.' Identifies the unsolved problem: 'A prime need in cryosurgical research is related to the periphery of the cryosurgical lesion where some cells die and others live.' Scope limits: 1998; a synthesis of laboratory and clinical work across tissues and species, not confined to skin and not confined to human data; the -50 degrees C figure is stated for neoplastic tissue, not for benign lesions.
  13. Costello JT, Baker PR, Minett GM, Bieuzen F, Stewart IB, Bleakley C. Whole-body cryotherapy (extreme cold air exposure) for preventing and treating muscle soreness after exercise in adults. Cochrane Database of Systematic Reviews 2015;9:CD010789. PMID 26383887.Tier 1Supports: Included only to define the boundary: whole-body cryotherapy is a different intervention, described here as 'a single or repeated exposure(s) to extremely cold dry air (below -100 degrees C) in a specialised chamber or cabin for two to four minutes per exposure'. Four laboratory-based randomised trials, 64 physically active predominantly young adults (mean age 23), all but four male. 'The evidence for all outcomes was classified as very low quality based on the GRADE criteria.' Muscle soreness at 1 hour SMD -0.77 (95% CI -1.42 to -0.12, 20 participants), at 24 hours SMD -0.57 (95% CI -1.48 to 0.33) and 48 hours SMD -0.58 (95% CI -1.37 to 0.21). 'None of the trials reported active surveillance of predefined adverse events.' Conclusion: 'There is insufficient evidence to determine whether whole-body cryotherapy (WBC) reduces self-reported muscle soreness... The lack of evidence on adverse events is important given that the exposure to extreme temperature presents a potential hazard.' Scope limits: outcome is post-exercise muscle soreness only; says nothing about skin, lesions or pigment; searches closed August 2015.Funding / interest: Two review authors (Costello, Bieuzen) co-authored included studies; inclusion decisions, risk-of-bias assessment and data extraction for those studies were handled by the other four authors.
  14. Ho D, Jagdeo J. A Systematic Review of Paradoxical Adipose Hyperplasia (PAH) Post-Cryolipolysis. Journal of Drugs in Dermatology 2017;16(1):62-67. PMID 28095535.Tier 3Supports: Included to define the boundary with cryolipolysis. Systematic search of PubMed, EMBASE, Web of Science and CINAHL on 26 July 2016 for 'cryolipolysis'; 314 records returned, 10 suitable, identifying 16 published cases of paradoxical adipose hyperplasia after cryolipolysis. Conclusion: 'we identified that the current incidence of PAH may be higher than previously reported' and 'the pathoetiology of PAH is currently unknown'. Note the regulatory framing in the paper: the CoolSculpting System (ZELTIQ Aesthetics) was 'FDA-cleared' in 2010 for flanks and subsequently for other sites — a US clearance, which carries no legal weight in the UK. Scope limits: tier 3 despite being labelled a systematic review, because it pools 16 published case reports with no denominator; it cannot generate a true incidence, and the review is now nine years old.Funding / interest: No funding or conflict statement is recorded in the PubMed entry; the publisher full text could not be retrieved to check.
  15. Tzellos T, Kyrgidis A, Mocellin S, Chan AW, Pilati P, Apalla Z. Interventions for melanoma in situ, including lentigo maligna. Cochrane Database of Systematic Reviews 2014;12:CD010308. PMID 25526608.Tier 1Supports: Searched to November 2014 across EIGHT databases (Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, African Index Medicus, IndeMED of India, IMSEAR) plus five trials registries, for RCTs of any intervention for melanoma in situ including lentigo maligna. 'Our search identified only 1 study eligible for inclusion' - a 90-participant open-label trial of imiquimod plus tazarotene versus imiquimod alone (91 LM lesions; complete response 66% versus 59%, RR 1.12, 95% CI 0.81 to 1.55). No RCT of cryosurgery for melanoma in situ or lentigo maligna was identified; indeed no RCT of any surgical intervention was identified. Authors' conclusions: 'There is a lack of high-quality evidence for the treatment of MIS and LM'; surgical interventions 'remain the most widely used and recommended available treatment'; non-surgical interventions 'may be considered in selected cases where surgical procedures are contraindicated and used preferentially by experienced providers under close and adequate follow up'. Scope limits: RCTs only, so it does not evaluate the case-series literature on cryosurgery for lentigo maligna; searches close in 2014. It is cited here for the honest negative - the absence of controlled evidence - not as a finding against cryosurgery.Funding / interest: All six authors declared nothing to declare.
  16. CryoPen UK (Ivanmed Ltd), cryopen.co.uk - homepage and FAQs. Site states the devices are 'created and manufactured in Belgium'; it does not name the Belgian manufacturer on the pages cited here.Tier 4Supports: Manufacturer/distributor marketing material, re-verified 2 August 2026 (FAQ quotes verified on cryopen.co.uk/faqs/; the aftercare and FDA claims verified on the homepage). Useful because it states the pigment risk plainly in its own words: 'Melanocytes are the most sensitive to cold injury. Therefore, they are the most easily damaged with cryosurgery. Dark skinned patients should consider the risk of permanent loss of pigment.' And the diagnostic boundary: 'No moles should be treated unless approved and assessed by a medical physician.' Also lists caution where 'the colour is cosmetically important such as face, ears, scrotum and lateral surface of fingers', and advises consulting a doctor where there is impaired sensation, impaired circulation, superficial nerves, open wounds, skin cancer, cold hypersensitivity or cardiac disease. Freeze-time claims: 'A typical freeze on viral infections may last from 5 to 10 seconds for a small flat wart, and up to 45 seconds for a full thickness plantar wart. For general purposes, most lesions take about 2 to 30 seconds', with a stated 'penetration rate of 1 mm per 5 seconds'. On pigment: 'Both hypopigmentation and hyperpigmentation may occur after cryosurgery, generally last a few months, but can be longer lasting.' Unsupported absolute claims on the same site: 'There's no cut, no bleeding, no sutures and no risk of infection'; homepage 'There is also no after-care needed for treatments'; and 'CryoPen is both CE certified and FDA approved allowing for the safest Cryosurgery treatments' — FDA clears rather than approves most such devices, and a US determination has no legal force in the UK. The homepage claim of no aftercare is contradicted by the site's own FAQ, which describes blistering for up to 5 days and healing over 2-6 weeks.Funding / interest: COMMERCIAL. Vendor material published by the UK distributor. UK supplier named on the site as Ivanmed Ltd ('Ivanmed is the sole UK supplier of CryoPen'), confirmed at Companies House as IVANMED LTD, company number SC601309, incorporated 29 June 2018, status Active, registered at 1 Johns Place, First Floor, Edinburgh EH6 7EL. The site says the devices are manufactured in Belgium but does not name the manufacturer on the pages cited; the attribution to H&O Equipments could not be verified from these sources and is therefore not asserted. Every claim on the page exists to sell devices and cartridges.
  17. CryoPen, Inc. (United States), cryopen.com - homepage and physician marketing. Content verified against the Internet Archive capture of 1 September 2022 (web.archive.org/web/20220901042956/http://www.cryopen.com/).Tier 4Supports: US vendor marketing, cited as evidence of how the modality is sold rather than as evidence of effect. On 2 August 2026 the live host cryopen.com did not complete a TLS handshake from this connection, so every quotation below was verified against the Internet Archive capture of 1 September 2022. Lists under 'CryoPen Treatment Uses - Treatment without referral for:' the following: 'warts/plantar warts, lentigo, dermatafibroma, seborrheic keratoses, non-recurrent basal cell, molluscum, actinic keratoses, keloids, skin tags, and more'. Marketing basal cell carcinoma as treatable 'without referral' is directly contrary to NICE NG12 recommendation 1.7.5 and to the requirement for histological confirmation. Also markets the procedure on revenue - 'One lesion a day can earn you $18,000 a year' - and describes it as a 'simple non-technique dependent procedure', a claim contradicted by the freeze-duration gradient in the BAD guideline and Thai 2004. Scope limits: US site aimed at US physicians; the captured page carries injected spam links (gambling text sitting inside the treatment list) and Adobe Flash instructions, indicating it is not actively maintained; the quotations are as at 2022, not 2026.Funding / interest: COMMERCIAL. Vendor material published by CryoPen, Inc., a device manufacturer and seller of the CryoPen Surgical System and its consumables.
  18. Medicines and Healthcare products Regulatory Agency. Medical devices: conformity assessment and the UKCA mark. GOV.UK guidance.Tier 1Supports: Confirms the framework: medical devices placed on the Great Britain market are governed by the 'Medical Devices Regulations 2002 (SI 2002 No 618, as amended)', with the MHRA as regulator, and 'The UKCA mark is a product marking which can be used for medical devices placed on the Great Britain (England, Wales, Scotland) market.' Scope limits: the page retrieved did not set out the current transitional dates for CE-marked devices in Great Britain, so no date claim is made here. Northern Ireland follows a separate route not covered by this page.
  19. Joint Council for Cosmetic Practitioners (JCCP), public register and modality listing, jccp.org.uk.Tier 4Supports: Accessed 2 August 2026. The JCCP register is organised around 'non-surgical and hair restoration surgery treatments (Injections, Fillers, Lasers, Peels and Hair Restoration Surgery)', with practitioner categories listed as botulinum toxins; dermal fillers; chemical peels and skin rejuvenation; lasers, IPL and LED treatments; and hair restoration surgery. Cryotherapy and skin lesion removal do not appear anywhere in the modality listing. The JCCP's own Press Release 31, 'JCCP publish guidelines on Adjunctive Therapies and Orphan Treatments', supplies the vocabulary used in this entry: 'There are five core modalities in non-surgical aesthetics which the JCCP and the CPSA (The Cosmetic Practice Standards Authority) have mapped and published standards against... the JCCP also wishes to acknowledge and affirm its position on the range of treatments which may sit outside of our recognised five referred to as "adjunctive" which may be complimentary to primary treatments or "orphan treatments" which may be stand alone.' That guidance sets generic obligations (work within your defined scope of practice, meet the premises standards, comply with CQC or Scottish registration where applicable) but names no specific modality standard for cryotherapy - it does not mention cryotherapy, cryocautery or lesion removal at all. This is the basis for treating lesion cryotherapy as an adjunctive or orphan modality: there is no JCCP/CPSA benchmark competence standard for it, and no register entry that signals competence in it. Scope limits: the JCCP is a voluntary self-regulatory body, not a statutory regulator; absence from its register is not a prohibition, it is an absence of a standard.
  20. Department of Health and Social Care. 'The licensing of non-surgical cosmetic procedures in England: consultation document'. Consultation opened 2 September 2023, closed 11:59pm on 28 October 2023 (page last updated 7 August 2025).Tier 1Supports: Proposal only, not law. The proposed amber tier covered procedures with medium risk; for a non-healthcare professional it would require a licence and 'relevant oversight by a named regulated healthcare professional'. The amber list includes, verbatim: 'cryotherapy and/or any cryocautery procedure that freezes the skin in order to remove skin lesions such as skin tags, age spots and warts'. The document repeatedly says the lists are indicative and may change. Scope limit: England only; this consultation did not create a licensing scheme.
  21. Department of Health and Social Care. 'The licensing of non-surgical cosmetic procedures in England: consultation response'. Published 7 August 2025.Tier 1Supports: The response reproduces the proposed amber list, including verbatim 'cryotherapy and/or any cryocautery procedure that freezes the skin in order to remove skin lesions such as skin tags, age spots and warts', but does not confirm that placement. It states: 'further work is required to determine where specific procedures will sit in the proposed tiering system and to determine which practitioners should be permitted to carry out certain procedures'; it also records requests for 'further scoping work' on cryocautery. Scope limit: England only; no non-surgical cosmetic-procedure licensing scheme is in force as at August 2026, and the response is not commencement legislation.
  22. Public Health (Wales) Act 2017 (anaw 2), section 57 'What is a special procedure?'. In force 29 November 2024 by S.I. 2024/1248.Tier 1Supports: Fetched and read. Verbatim: 'Each of the following is a special procedure for the purposes of this Part— (a) acupuncture; (b) body piercing; (c) electrolysis; (d) tattooing.' Commencement: 'S. 57 in force at 29.11.2024 by S.I. 2024/1248, art. 2(b)'. Cryotherapy is not one of the four statutory special procedures. Scope limit: Wales only; the Act says nothing about the position in England, Scotland or Northern Ireland.