Clinical and aetiological aspects in urticaria and angio-oedema.

Urticaria is a common disorder that affects as many as 20% of all people at some time during their lifetime. To analyse the prevalence of various forms of urticaria according to an aetiological and clinical classification, we carried out a 4-year study in an outpatient clinic. The study was carried out on 562 consecutive patients (178 males and 384 females; mean age 35.4 +/- 16), who had been referred to our unit for the study of urticaria and angio-oedema. Baseline investigations included: the patient's family and personal history of allergy; duration of symptoms, presence of associated symptoms and objective signs of the current episode; clinical, laboratory and instrumental investigations; assessment of response to antihistamine treatment. A family history of atopy was present in 35% of patients and a personal history of allergy in 24%. We subdivided urticaria and angio-oedema into several groups on the basis of their clinical and aetiological aspects. Of the 562 patients, 424 (76%) presented with ordinary urticaria (43 acute urticaria, 311 chronic urticaria, 70 episodic urticaria), 80 (14%) physical urticaria, 49 (9%) angio-oedema without weals, six (1%) IgE-mediated contact urticaria and three (0.5%) urticarial vasculitis. In 64 cases (11%) urticaria/angio-oedema was associated with one or more symptoms. We identified 394 cases (82%) of idiopathic urticaria, 42 (9%) of immunological urticaria, 29 (6%) of non-immunological urticaria and 17 (3%) of urticaria secondary to infections. Of the treated subjects, 54% showed a good response to treatment with antihistamines. Our data provide an overview of urticaria/angio-oedema in a large series of patients, based on clinical-aetiological aspects, and related to recent diagnostic guidelines.