After trying unsuccessfully to help Mary, a 39-year old patient, with painful lesions on her toes that had been present for six weeks, one of our locums asked a partner who has an interest in dermatology to help.
Mary also had an erythematous flaking rash on her face, and the locum's provisional diagnosis was systemic lupus erythematosis (SLE). However, all the laboratory investigations, including ESR and Hb, and autoimmune profiles, including antinuclear antibodies, were normal.
Our partner established that Mary's problem had begun with redness and itching at the tips of her toes. This progressed to tenderness, and some pale lesions like small blisters then appeared.
She had never suffered from this before. She was otherwise well, had no systemic symptoms, and was not taking any drugs except for an occasional paracetamol. She did not smoke, and drank only an occasional glass of red wine.
Our partner thought the facial rash was seborrhoeic dermatitis and not relevant to the toe problem.
Making the diagnosis
Having seen many such cases, our partner made a diagnosis of perniosis (chilblains), lesions that can occur on the fingers as well as toes. Although a minor problem, they may be troublesome to some patients and reassurance and advice can be valuable.
Chilblains are thought to be caused by environmental factors, combined with some underlying but non-specific susceptibility in the patient. The theory is that intermittent and prolonged cold causes vasoconstriction, leading to hypoxia of the tissues, and inflammatory changes in the wall of the blood vessels.
As the toes (or fingers) warm up, fluid from the blood vessels can leak into the surrounding tissues, resulting in areas of inflammation and swelling.
Biopsy is unnecessary, but where this has been done there are local inflammatory changes, perivascular lymphocytic infiltrates and dermal oedema.
The rate of temperature change is probably involved in the process, as it seems that if a cold appendage is warmed up too quickly, such as putting a heat pad on the affected area, it is more likely to cause or at least aggravate the development of chilblains. Beta-blockers may aggravate chilblains in some patients.
Most cases of chilblains seen by GPs are simple, or primary, but they may occur secondary to others including SLE, antiphospholipid antibodies, myelomonocytic leukaemia and as a reaction to some medications.
The main differential diagnosis is Raynaud's phenomenon.
Important differences are the much shorter duration of episodes of Raynaud's (hours rather than days), and the three stages of change in Raynaud's.
These are white fingers or toes that become blue with cyanosis and then become red with erythema. Rarely, vasculopathies and vasculitis may present as chilblains.
OTC treatments are not of proven value, and steroid creams are not advised. Advice on prevention is paramount; avoid the cold where possible and keep the toes and fingers warm if exposure is inevitable.
Once precipitating factors are avoided, the lesions should quickly heal by themselves. Nicotine, caffeine and decongestants are likely to aggravate vasoconstriction and should be avoided.
- Dr Barnard is a former GP in Fareham, Hampshire.