Dermatology & Internal Medicine & Family Medicine
Frostbite
Frostbite - called perniosis (or pernio in Latin) in the medical literature - is an inflammatory, non-frozen skin lesion resulting from an abnormal reaction of the cutaneous microcirculation to repeated exposure to damp cold and sudden thermal variations, without the tissue actually freezing. This distinguishes them from frostbite, which involves actual tissue freezing with the formation of intracellular crystals. The pathophysiology is based on prolonged arteriolar vasospasm in response to cold, followed by excessive reactive vasodilation on rewarming - resulting in increased capillary permeability, localized edema and a characteristic perivascular inflammatory reaction. Frostbite typically occurs with prolonged exposure to cool, damp temperatures (0 to 15°C) - it is more common than you might think in temperate-cold climates like Quebec, where humidity aggravates the perception and biological effect of cold even at moderate temperatures. Young, slim women of constitutional ectomorphic type, people with Raynaud's phenomenon or increased vasomotor sensitivity, children and the elderly are the most vulnerable. Frostbite tends to affect the most exposed and least vascularized extremities: fingers, toes, ears, nose, cheeks and thighs (especially the backs of thighs for female riders and winter sports enthusiasts wearing jeans - which don't protect against the damp cold). In the vast majority of cases, frostbite is idiopathic and benign, resolving spontaneously within a few weeks of cessation of exposure. However, their seasonal recurrence, functional impact (pain, intense pruritus) and possible association with underlying systemic diseases (systemic lupus erythematosus, cryoglobulinemia, antiphospholipid syndrome) warrant medical evaluation, particularly in atypical, severe or persistent forms beyond the cold season.
Clinical presentation, forms and risk factors
- Typical clinical presentation : lesions appearing 12 to 24 hours after exposure to damp cold - erythematous to purplish papules, plaques or nodules, 1 to 3 cm in diameter, edematous, with ill-defined edges, sometimes slightly raised; location: fingers and toes (dorsal surface - 1st and 5th rays often spared) + ears + nose + cheeks + heels + posterior surface of thighs; symptoms : intense pruritus + burning sensation + pain on palpation + characteristic aggravation on warming (return to a warm place → onset of disabling itching); spontaneous resolution in 1 to 3 weeks with the end of cold exposure; severe forms: bullae + ulcerations + scabs - slower healing (4 to 6 weeks) with risk of residual pigmented scars
- Special clinical forms : perniosis of the thighs (pernio equestre): purplish patches on posterior and lateral thighs - women wearing non-insulating clothing in winter (damp jeans, leggings) - young women + horse riders + cross-country skiers; perniosis associated with anorexia nervosa: defective skin microcirculation + absence of insulating fat mass + malnutrition → severe, recurrent frostbite at mild temperatures; perniosis chilblain lupus : association with cutaneous lupus erythematosus - chronic, induced, purplish lesions of fingers + ears + nose + in a woman between 30 and 50 years of age - biopsy essential (deep perivascular lymphocytic infiltrate) + ANA, anti-dsDNA, complement workup; COVID-19 frostbite (COVID toes): cutaneous manifestation described in 2020 - erythematoviolent lesions of toes and fingers in young patients with asymptomatic or mild COVID picture - mechanism debated (micro-thrombosis + viral vasculitis) - spontaneous resolution in a few weeks
- Risk factors and associated diseases : constitutional factors: low BMI + ectomorphic constitution + young woman + primary or secondary Raynaud's phenomenon + constitutional acrocyanosis; systemic diseases to be excluded in severe or atypical forms: systemic lupus erythematosus (SLE - ANA + anti-dsDNA + complement) + cryoglobulinemia (chronic hepatitis C - serum cryoglobulins) + antiphospholipid syndrome (IgG/IgM anticardiolipin antibodies + anticoagulant lupus) + monoclonal gammopathy + chronic lymphocytic leukemia (CLL) + polycythemia vera + dysproteinemias; vasoconstrictive drugs that promote: beta-blockers (propranolol, atenolol) + triptans + ergotamine + amphetamines + cocaine
- Differential diagnosis : frostbite - frozen, white, anesthetized tissue, bullous after rewarming - temperatures <0°C - emergency; Raynaud's syndrome - paroxysmal episodes of pallor + cyanosis + reactive erythema (tricolor triad) in extremities when cold - without permanent skin lesions between attacks; lupus pernio (sarcoidosis) - purplish nodules of nose + cheeks + ears - biopsy : epithelioid granulomas - not to be confused with idiopathic perniosis; leucocytoclastic vasculitis - vascular purpura + characteristic biopsy; erythema multiforme - bilateral target lesions + often mucosal involvement - infectious (HSV) or drug-induced trigger
Treatment and prevention
| Treatment | Mechanism, technique and procedures | Effectiveness, duration and precautions |
|---|---|---|
| General measures and warming 1st-line treatment - essential and immediate |
Withdrawal from cold exposure: immediately cease all exposure to damp cold - return to a heated environment + change wet clothes + gently dry the affected area; passive, gradual rewarming: allow lesions to warm up at room temperature - never rub affected areas vigorously (risk of trauma to weakened skin) - never apply a direct heat source (hot water bottle, hot water, open fire) to numb or insensitive frostbitten skin (risk of heat burns on skin with altered sensitivity); mechanical protection: non-compressive, non-adhesive dressings (Mepilex, Adaptic) on ulcerated or bullous lesions; elevation of lower limbs if associated edema; maintenance of general body heat: hot, sweet drinks + sufficient food (thermogenesis); smoking cessation: nicotine is a powerful peripheral vasoconstrictor - aggravates microcirculation and perniosis - cessation essential in recurrent forms. | Progressive rewarming to room temperature is the most important and safest measure - over-rapid rewarming with direct heat can aggravate pain and lesions by inducing abrupt reactive vasodilatation on skin that is not very sensitive; spontaneous resolution is the rule in simple frostbite within 1 to 3 weeks with cessation of exposure - inform the patient that pruritus worsens transiently during rewarming (normal reaction) before subsiding; for patients with associated Raynaud's phenomenon: learn thermal protection techniques + gradual rewarming at the first vasospastic signs (before lesions appear); for patients with professional exposure to cold (outdoor workers): merino wool socks + silk under-gloves + waterproof gloves + insulating footwear + layering + avoid cotton, which retains moisture. |
| Dermocorticoids and local care Reduces local inflammation and pruritus |
Topical corticosteroids (dermocorticoids): apply 1 to 2 times/d to active erythematous lesions (papules, plaques, pruritic nodules) during the inflammatory phase - moderately potent to potent class: triamcinolone 0.1 % (Kenalog cream) or mometasone 0.1 % (Elocom cream) × 1/d × 7 to 14 days on limbs + hydrocortisone 1 % or desonide 0.05 % on face and sensitive areas (nose, ears); oral antihistamines (anti-H1): hydroxyzine (Atarax) 25-50 mg at bedtime (sedative effect + antipruritic) or cetirizine (Reactine) 10 mg × 1/d during the pruritic phase - do not treat the cause but improve comfort, notably sleep quality; local care of ulcerated lesions: cleansing with saline solution + non-adhesive oily dressing (Vaseline gauze, Adaptic) changed daily - no aggressive antiseptics (alcohol, concentrated hydrogen peroxide) on ulcerations - oily tulle or Mepitel if ulcerations are extensive; emollient moisturizing cream: apply after dermocorticoids to maintain skin barrier (Cerave, Glaxal Base, Vaseline) - improves tolerance and healing | Dermocorticoids reduce local inflammation and pruritus but do not act on the underlying vasomotor mechanism - they are useful for comfort but do not significantly shorten the time to resolution of frostbite; do not use dermocorticoids on active ulcerations or superinfected lesions; duration of application limited to 10 to 14 consecutive days to avoid skin atrophy - particularly on the face and thin areas (fingers, ears); sedative antihistamines (hydroxyzine) are particularly useful if nocturnal pruritus disturbs sleep - to be used occasionally as a short course of treatment, not on a long-term basis |
| Nifedipine and vasodilators Recurrent or severe forms - calcium channel blocker |
Nifedipine (Adalat) extended-release: L-type calcium channel blocker - powerful peripheral arteriolar vasodilator - reduces cold-induced vasospasm causing frostbite; dosage: nifedipine LP 30 mg × 1/d (or 20 mg × 2/d) per os - start at 10 mg/d and gradually increase if hemodynamically tolerated - maintain throughout the cold season or until lesions resolve; indications: recurrent frostbite season after season + severe frostbite with ulcerations + disabling frostbite resistant to local measures + associated secondary Raynaud's phenomenon; alternative: diltiazem LP 60-120 mg × 1/d (non-dihydropyridine calcium channel blocker) if nifedipine poorly tolerated; amlodipine (Norvasc) 5 mg × 1/d: another option (better tolerated than immediate-release nifedipine - less abrupt hypotensive effect); pentoxifylline 400 mg × 3/d : rheological agent (improves erythrocyte deformability + reduces blood viscosity) - complementary option in resistant forms; doxycycline 100 mg × 2/d × 3 weeks: limited data but some series suggest a benefit (anti-inflammatory effect + possible effect on microcirculation) | Nifedipine is the best-documented pharmacological agent for recurrent frostbite (Dowd 1986 Br J Dermatol - reduced severity and frequency of lesions on nifedipine vs. placebo); side effects of nifedipine: flushing + headache + orthostatic hypotension (especially at start of treatment) + ankle edema + reflex tachycardia - start at low dose and increase gradually; contraindications to nifedipine: pre-existing arterial hypotension + severe heart failure + pregnancy (1st and 3rd trimesters - teratogenicity and effects on fetal circulation) + association with grapefruit juice (CYP3A4 inhibition → increased toxicity); nifedipine is not reimbursed by RAMQ for frostbite (off-list indication) - reimbursed for hypertension and angina |
| Assessment of associated systemic diseases Atypical, severe or persistent forms |
Indication for systemic workup: frostbite persisting beyond the cold season (> April-May in Quebec) + severe form with deep ulcerations + strict bilaterality + age >50 years with no usual risk factors + indurated lesions + unusual involvement (trunk, thighs) + associated systemic signs (fatigue, arthralgia, alopecia, photosensitivity); recommended workup: CBC + ESR + CRP + ANA (antinuclear antibodies) + anti-dsDNA (lupus-specific) + complement C3 and C4 + antiphospholipid antibodies (lupus anticoagulant + anticardiolipin IgG/IgM + anti-beta2-GP1) + serum cryoglobulins (tubes kept at 37°C until laboratory - special sampling) + serum protein electrophoresis (EPPS) + immunoelectrophoresis + anti-Ro (SSA) and anti-La (SSB) antibodies (Sjögren + neonatal lupus) + TSH (hypothyroidism favoring vasomotor disorders) + HCV serology (mixed cryoglobulinemia) ; skin biopsy : if suspected chilblain lupus or atypical form - histology: deep perivascular lymphocytic infiltrate + PAS deposits + IFD (direct immunofluorescence) | The vast majority of frostbite cases (80-90 %) are idiopathic in young people with constitutional factors - systemic workup is reserved for atypical or severe forms; chilblain lupus (lupus pernio cutaneum) is an entity in its own right - frostbite is often the 1st manifestation of lupus and may precede diagnosis by several years - skin biopsy essential + full autoimmune workup ; type II mixed cryoglobulinemia (associated with HCV) can manifest as frostbite + palpable purpura + arthralgia + peripheral neuropathy → systematic HCV screening in this situation; low-level positive ANA (1/320) + compatible clinical picture justifies a full rheumatological investigation. |
| Preventing seasonal recurrences Thermal protection - healthy living |
Optimum thermal protection for extremities: waterproof + insulating gloves (merino wool or Gore-Tex gloves) - change wet gloves immediately + merino wool socks (avoid cotton, which retains moisture) + well-fitting insulating waterproof footwear (do not wear too tightly - risk of vascular compression) + hat covering ears + neck warmer + thermal underwear covering thighs (thermal leggings); layering strategy: base layer in merino wool or polypropylene (wicks away perspiration) + insulating layer (wool, down, fleece) + windproof waterproof outer layer; avoid constricting clothing (socks too tight, rings) that compromise distal microcirculation; maintain good hydration and nutrition: central hypothermia promotes peripheral vasoconstriction - maintain adequate nutrition and hydration in cold environments; nifedipine LP for seasonal prevention: start at the beginning of autumn (October) in patients with severe recurrent frostbite - maintain until the end of risk periods (April); discontinue vasoconstrictive drugs if possible (beta-blockers → replace with another antihypertensive if absolute non-cardiac indication) | Prevention is by far the most effective strategy - rigorous thermal protection of the extremities can prevent almost all recurrences in patients at constitutional risk; inform patients that wet denim jeans are a major risk factor for thigh frostbite in Quebec in autumn and spring - education on appropriate clothing is an important primary prevention measure ; nifedipine for seasonal prevention (started before exposure to cold) is more effective than its purely curative use (lesions already formed) - preferable to start in September-October in patients with documented annual recurrences; hand warmers (chemical tablets) can be useful as an adjunct, but do not replace insulating gloves - beware of the risk of burns if placed directly on the skin of an insensitive person |
ℹ️
Frostbite vs. frostbite - an essential clinical distinction : Frostbite (perniosis) is often confused with frostbite, but the two entities are fundamentally different. Frostbite occurs at cool, non-freezing temperatures (0 to 15°C) with humidity, without tissue crystallization - the tissues are not frozen - and progresses to complete healing within a few weeks. Frostbite involves actual tissue freezing (temperatures <0°C) with intracellular crystal formation, cell necrosis and risk of amputation if severe - it constitutes a medical-surgical emergency. Clinically, frostbite presents as cold, white, waxy, hard, anesthetized skin, followed by hemorrhagic bullae and black necrosis after rewarming. Management is radically different: for frostbite, rapid rewarming in warm water (37-42°C), systemic ibuprofen, anticoagulation, and sometimes intravenous thrombolysis or iloprost in severe forms in specialized centers.
Signs requiring prompt medical attention
Consult your doctor promptly if : lesions that do not heal after 3 to 4 weeks despite cessation of exposure and local treatment, or lesions that persist outside the cold season → assessment of systemic disease (lupus, cryoglobulinemia) essential.
Deep ulceration + skin superinfection (pus, odor, perilesional cellulitis, fever) → oral antibiotic therapy and specialized local care as a matter of urgency.
Severe chilblains with signs of digital ischemia (fingers or toes completely white, cold, numb, painful) → urgent evaluation to exclude frostbite, arteriopathy or secondary severe Raynaud's syndrome.
Consult at Clinique Omicron
Clinique Omicron physicians evaluate and treat recurrent or severe frostbite - clinical diagnosis, local care, prescription of nifedipine if indicated, systemic disease workup for atypical forms, and referral to dermatology or rheumatology if necessary. Consultations are available at our points of service in Quebec and via telemedicine for seasonal follow-up. To book an appointment, visit cliniqueomicron.ca.
The content of this page is provided for informational purposes only and does not replace the advice of a qualified healthcare professional. Persistent frostbite or frostbite associated with systemic signs should be medically evaluated to exclude underlying disease.
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