Dermatitis herpetiformis (DH) is an external manifestation of coeliac disease presenting with blistering rash and pathognomonic cutaneous IgA deposits. Better knowledge of subclinical forms and serological testing has resulted in a sharp increase in the incidence and prevalence of coeliac disease.
To investigate the prevalence of DH and analyse whether the incidence of DH changed when the occurrence of coeliac disease increased.
All 477 patients with DH diagnosed from 1970 onwards at the Tampere University Hospital were analysed for prevalence in 2009. The incidence of DH was calculated in three 10-year periods from the year 1980.
The prevalence of DH was 75·3 per 100,000 which is eight times lower than the prevalence of coeliac disease in our area. The annual incidence of DH in the whole period was 3·5 per 100,000, and in the three 10-year periods 5·2, 2·9 and 2·7 per 100,000, respectively. The decrease in incidence between the first and second 10-year period was significant (P