Epidemiological patterns of perniosis, and its association with systemic disorder.

BACKGROUND: There are few studies exploring the epidemiological properties of perniosis (chilblains) and its association with systemic disorders.

AIM: To collect epidemiological data for perniosis, to investigate any association with systemic disorders, and to identify markers for the differential diagnosis of idiopathic and secondary perniosis.

METHODS: This was a prospective study of 51 patients with perniosis [female : male ratio 2.64 : 1, mean ± SD age 24.6 ± 14.7 years, with 25 patients (49%) aged 0-18 years]. Each patient was interviewed, and signs suggestive of connective-tissue disorders were recorded. Detailed laboratory investigations including autoimmune parameters were performed.

RESULTS: Significant proportions of the patients had both chronic and idiopathic perniosis (P < 0.001 for both). The mean age of the group with secondary perniosis was significantly higher than that of the idiopathic group (P < 0.01). There was no significant gender difference in the secondary perniosis group (P = 0.71). Clerking work was the most common occupation (37%, P = 0.01). Persistence beyond the cold seasons, and presence of photosensitivity, hypergammaglobulinaemia and rheumatoid factor were significant findings in the secondary group (P = 0.02, P = 0.02, P < 0.01, P < 0.05, respectively).

CONCLUSIONS: Perniosis is not rare in children, but patients with secondary perniosis are more likely to be older. In terms of underlying systemic disorder, advanced age and male gender may be important demographic features. Measurement of cryoglobulin levels in the initial laboratory investigations of patients with perniosis is not necessary. Persistence beyond the cold seasons, and presence of photosensitivity, hypergammaglobulinaemia and rheumatoid factor may be useful in differentiating between idiopathic and secondary perniosis.