An approach to urticaria.

As the problem of chronic urticaria is frustrating both to the physician and patient, an attempt to study its aetiology was made. 100 cases of chronic urticaria was studied in 1979. Patients having daily urticaria for more than 6 weeks, were included. There were 52 males and 48 females. A detailed history of the pattern of urticaria, drugs, physical causes, diet and illnesses were asked for, followed by physical examination. Each were then screened through a Diagnostic Tray including basic haematological tests, urinalysis, stools analysis, physical allergy tests, food provocation battery and further special tests. 17 patients had physical urticaria, cold (6), pressure (5), delayed dermographism (1), cholinergic (4), solar (1). 4 patients had severe reactions with aspirin, one with tetracycline; one had undiagnosed thyrotoxicosis. 36 of all the patients had a positive test on provocation with the food battery: aspirin (13), preservatives (3), colour dyes (6), yeast (1) and others (15). It has been suggested that these are not the immediate cause but are aggravating factors. 48% of patients showed dermographism. The number of idiopathic cases about 77% is consistent with the findings of others. We feel that an attempt to exclude treatable causes has brought reassurance to many of the patients. Long term antihistamine therapy was given in these cases.