Symptomatic dermographism: Natural history, clinical features, laboratory investigations and response to therapy §

Summary Fifty patients with a history of symptomatic dermographism were investigated. The mean age of onset was 25·75 years (range: ‘from birth’ to 52 years) and the peak age of onset was in the second and third decades. The mean duration at last follow‐up was 5–1 years (range: 3 months to 47 years). The duration was longer than 5 years in 22%, and longer than 10 years in 10% of the patients. Ninety‐two percent of patients, but not a single member of an age‐matched group of sixty control subjects, produced measurable wealing at a pressure of 3·5 × 10 5 Pa or less applied with a calibrated dermographometer. The incidence of the atopic diathesis was not increased in patients with symptomatic dermographism, and no associations with systemic diseases, food allergens or medications were established‐ Routine haematological, biochemical, microbiological and intradermal screening tests were not found to be helpful in the management of this condition. Protease inhibitor profiles revealed a significant reduction in the level of circulating a i‐antitrypsin inhibitor which was not the result of a genetic difference between the patient and control groups. In a double‐blind randomized controlled trial of eight different antihistamine regimes in twelve patients, a combination of hydroxyzine (10 mg qds) and cimetidine (400 mg qds) proved significantly superior to all other treatments in reducing dermographometer‐induced wealing, and was associated with fewest side‐effects.