Objective To determine the incidence and presenting features of coeliac disease and dermatitis herpetiformis in the population of South Glamorgan between 1981 and 1995. Design Retrospective case-finding study using pathology, dietetic and clinical records, data from hospital activity analysis, general practice records and a Coeliac Society questionnaire. Incidence rates were calculated using the Registrar General's mid-year estimates. Setting Regional hospitals, South Glamorgan, Wales. Participants All new cases of coeliac disease or dermatitis herpetiformis. Main outcome measures Crude incidence rates (per quinquennia) for both children and adults. Age, sex, family history, symptoms at the time of diagnosis and time to diagnosis from symptom onset. Results In total, 137 cases of coeliac disease (27 children, 110 adults) and 19 cases of dermatitis herpetiformis were detected. In adults with coeliac disease, incidence rates have risen from 1.32 to 3.08 per 100 000 with a 3:1 female predominance. Almost 50% of adults were over fifty years old when diagnosed and 25% had no abdominal symptoms. In children, the disease incidence has remained stable but with a rising trend in mean age at diagnosis and higher likelihood of atypical symptoms in older children. There has been no change in the incidence of dermatitis herpetiformis. Only 8.3% of all patients had an affected first-degree relative. Conclusions In contrast to other reports of declining incidence, coeliac disease in children has remained constant in South Glamorgan, but has markedly increased in adults, particularly women. Presentation may be at any age, often with atypical symptoms, which may delay diagnosis.
