Chilblains are also known as pernio, or perniosis, but must be distinguished from lupus pernio, which is a cutaneous variant of sarcoidosis. Chilblains are localized purple/dusky inflammatory lesions that can burn and itch. The lesions are usually on the extremities and occur due to persistent exposure to damp, cold environments. Unlike frostbite, chilblains are not due to freezing temperatures.

The pathogenesis of chilblains isn’t known. There may be a vascular etiology, with an abnormal response of the blood vessels to cold. In kids, it may be associated with cryoproteins.

Chilblains have a seasonal onset, tending to occur mainly in the fall and winter. They most frequently occur in places that lack central heating, and were very common in Northwestern Europe in the 19^th century.

They manifest more often in women than men. The young, especially children, and the elderly are preferentially affected. Horseback riders often develop chilblains on the lateral thighs. The main risk factor is exposure to cold temperatures, above freezing, with high humidity. Being thin also predisposes to chilblains, and anorexia/bulimia are associated conditions. These factors exacerbate conductive heat loss.

Clinical features

Chilblains lesions are characteristically localized purplish macules, papules and nodules. They may be single or multiple. In more extensive or severe cases, lesions can blister and ulcerate. Deeper lesions, especially on the buttocks, outer thighs and calves may appear as blue-red plaques. Patients may complain of pain, burning and, less commonly, itch.

Lesions are often distributed symmetrically. The toes and fingers are usually the most affected regions. Other susceptible areas include the ears, nose, lateral outer thighs, lower legs and heels.

Varied course

Uncomplicated chilblains self-resolve after one to three weeks. There can be a prolonged course in elderly patients, especially with co-existing peripheral vascular disease. Lesions can become chronic. Only rarely do they persist into summer months.

Differential diagnosis

Chilblains can look identical to chilblain lupus; they’re distinguished by biopsy and other features of systemic lupus erythematosus. Raynaud’s phenomenon also appears on the fingers and toes, but colour changes are present — white to blue to red, resolves within hours, and is due to vasoconstriction. Lupus pernio (persistent purplish plaque on the nose) is a form of cutaneous sarcoidosis. Other conditions to consider and triggered by cold exposure include: erythrocyanosis — cold-induced lesions over thick, subcutaneous fat; cold urticaria — urticaria occuring after minutes of cold exposure; and cold panniculitis — subcutaneous fat inflammation.

Investigations

Chilblains can often be diagnosed by a good history and physical (see Table 1). They’re usually idiopathic, without any associations. However, investigations are usually done to rule out underlying conditions:

• anorexia
• connective tissue disease
  • chilblain lupus erythematosis, especially if lesions are bullous
• myelodysplastic or myeloproliferative disease
• cryoproteins — proteins that are insoluble in cold temperatures
  • especially in children
• peripheral vascular disease
  • especially in elderly patients with risk factors for atherosclerosis

Treatment

Patient education and behavioural modification are perhaps the most important component of treating chilblains. Advise patients to warm their house sufficiently, wear warm clothing, and keep their feet dry. They should also stop smoking and rest adequately.

The mainstay of medical management involves the use of vasodilators. Calcium channel blockers (CCBs) are effective in the majority of patients, stopping new lesion development within 1 week of therapy. Nifedipine 20-60 mg po daily, divided tid, and diltiazem 60-120 mg po tid are good options. Peripheral edema is a very common side effect of CCBs and may not be tolerated by all patients.

If CCBs aren’t tolerable or are contraindicated, consider topical agents. Topical corticosteroids are often used, but lack proven efficacy. Topical antipruritics can provide symptomatic relief. Other topicals have been used including nicotinic acid derivatives, and minoxidil 5% lotion. Phototherapy, both PUVA and UVB, provide questionable benefit.