Irish Society of Gastroenterology

Abnormalities of the thyroid gland are said to be common in patients with dermatitis herpetiformis (DH), treated with dapsone (Thyroid abnormalities in dermatitis herpetiformis. Cunningham andZone, Annals Int.Med. 1985: 102, 194-196). Thepossibility that the goitrogenic effects of dapsone may play a role in this has not been evaluated. We therefore studied thyroid abnormalities in 40 patients with DH, 25 of whom were taking dapsone and 15 of whom were on a gluten free diet alone. All patients were examined clinically for evidence of thyroid dysfunction and blood was drawn for total thyroxine, thyrotrophin levels and thyroid microsomal antibdy titres. Six (24%) of dapsone treated patients had thyroid abnormalities, compared to 1 (7%) of the 15 patients treated with diet alone. Two patients became thyrotoxic when on treatment with dapsone. One patient had myxoedema prior to diagnosis of DH and one developed myxoedema while on dapsone. Two patients with asymptomatic goitres at the time of screening were taking dapsone and one patient on dapsone had thyroid antibodies. Thus it seems likely that the increased incidence of thyroid abnormalities in DH may be related to the effects of the sulphonamide on thyroid function.