The incidence and prevalence of dermatitis herpetiformis in Utah.

BACKGROUND AND DESIGN

The incidence and prevalence of dermatitis herpetiformis has never been formally evaluated in any area of the United States. Several northern European studies have shown prevalence rates ranging from 1.2 per 100,000 to 39.2 per 100,000. The present study was performed to evaluate the incidence and prevalence of dermatitis herpetiformis in Utah. Information from 240 patients diagnosed with dermatitis herpetiformis was compiled from hospital records throughout Utah, as well as the sole private dermatopathologist in the state, and from the university referral center of the state. Criteria for inclusion in the study were a clinical diagnosis of dermatitis herpetiformis plus granular deposition of IgA in dermal papillae by direct immunofluorescence of uninvolved skin, or histopathologic findings consistent with the disease. Clinical diagnosis and response to dapsone alone was considered insufficient for inclusion in the study. On the basis of these criteria, as well as exclusion of non-Utah residents, 188 of the original 240 patients qualified for the study.

RESULTS

The prevalence of dermatitis herpetiformis in Utah in 1987 was 11.2 per 100,000. The mean incidence for the years 1978 through 1987 was 0.98 per 100,000 per year. The mean age at onset of symptoms for male patients was 40.1 years, and that for female patients was 36.2 years. The male-female ratio was 1.44:1.

CONCLUSIONS

This represents the first evaluation of the incidence and prevalence of dermatitis herpetiformis in the United States. These results are similar to those of the previous studies, probably because of Utah's largely northern European ancestry. This population base, plus a much smaller than average black and Oriental population, is likely to have produced a higher incidence and prevalence in Utah than would be seen in other areas of the United States.