(1975). Thorax, 30, 2-8. An analysis of skin prick test reactions in 656 asthmatic patients. Of 656 asthmatic patients referred specifically for allergy assessments, 544 (84%) gave positive immediate skin prick tests to at least one of 22 common allergens used routinely.Comparison of these skin test positive patients with the 102 (16%) who were skin test negative showed a number of significdnt differences. The majority of the skin test positive patients (52%) were less than 10 years old at the time of onset of the asthma, whereas, of the skin test negative patients, 56% were aged over 30 years at the time of onset. Seventy per cent reported rhinitis compared with 48% of the skin test negative patients, and 29% reported infantile eczema compared with 9%. Symptoms attributed to house dust, pollens, and animals were noted two to three times more frequently by the skin test positive patients, while corticosteroid drugs had been used more commonly by the skin test negative patients (45% compared with 35%).No significant differences were observed with the other factors studied, namely, history of urticaria or angio-oedema, family history of 'allergic' disease, and awareness of sensitivity to foods, aspirin or penicillin.Prick test reactions in the skin test positive patients were most commonly seen to house dust or the acarine mite, Dermatophagoides farinae (82%), followed by pollens (66%), animal danders (38%), foods (16%), Aspergillus fumigatus (16%), and other moulds (21%). There was a highly significant association of positive history with positive prick test for all allergens studied.Although the association between immediate wealing skin reactions and asthma has been recognized for many years (Coca and Cooke, 1923), the specificity of these tests, their relation to etiology, and their clinical significance has been in dispute. Rackemann (1947) suggested that the presence of positive skin reactions on routine prick testing with common inhalant and food allergens should place the asthmatic into the extrinsic (allergic) category where usually the onset of symptoms is early in life and the prognosis more favourable than in the intrinsic (nonallergic) category (Rackemann and Edwards, 1952;Rackemann, 1958).Raised serum IgE levels have been found in Present addresses: 1Department of Chest Diseases, United Oxford Hospitals
