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Clinical implications
Clinical implications
Patients with dermatitis herpetiformis have long been thought to have an increased risk of developing cancer
This study found that non-Hodgkin's lymphoma seemed to be the only cancer significantly more common in such patients
Male patients were at greater risk than female patients
Patients with dermatitis herpetiformis should be checked regularly for sign of lymphoma
Introduction
An increased incidence of gastrointestinal lymphoma has been documented in several studies of coeliac disease. Patients with dermatitis herpetiformis have long been thought to have an increased risk of developing cancer, and there are numerous case reports of patients with dermatitis herpetiformis and lymphoma. To our knowledge, however, no large study has been done to confirm this relation and estimate the risks of lymphoma. In a retrospective study of 109 patients with dermatitis herpetiformis malignant tumours were found in seven, giving a relative risk of 2.4. 1 In Sweden another retrospective study of 96 patients, however, failed to show any relation with malignancy. 2
It is therefore of interest to determine whether patients with dermatitis herpetiformis without clinical signs of coeliac disease are at risk of developing lymphomas. To provide more accurate estimates of the risk we studied a population based patient cohort of patients with dermatitis herpetiformis who were admitted to hospital in Sweden between 1963 and 1983. Follow up was complete up to 1987 and therefore ranged from five to 25 years after the first evaluation in hospital for dermatitis herpetiformis.
Patients and methods
Patients
From 1964 to 1983 the Swedish National Board of Health and Welfare collected nationwide information about people who were admitted to hospital in the country. In 1964, when this registry started, it covered only 20% of the population (8.3 million), but its coverage increased over the following years so that by 1969, 60% of the population was covered. Since 1970 this registry has been virtually nationwide. The information includes a unique individual identification number used in all population statistics in Sweden, the dates of admission and discharge, diagnosis, and nature and dates of operations.
From this registry we selected the diagnosis of dermatitis herpetiformis by using code 70400 from the Swedish adaptation of the International Classification of Disease, seventh revision (ICD-7), for 1964-8 and code 69399 from ICD-8...