Cat sensitivity: 7-yr audit in children attending a paediatric allergy clinic in North Italy.

Sensitivity to cats and exposure to cat allergen is a common cause of asthma exacerbation in children. To date, there is no data on the prevalence of cat sensitivity in children living in North Italy. Therefore, a 7-yr survey was performed in patients attending an allergy clinic for the first time. Skin prick tests (SPT) for perennial allergens and for pollens relevant to the region were performed in 4,957 children attending the outpatient clinic 1992-1998. A questionnaire on present or past cat ownership was presented to all cat-skin prick test positive children. An evaluation of cat ownership on the general population was made by telephone interview on a random sample of 1,268 families living in the same area. With a 3-mm wheal as a positive cut-off 439 (8.85%) children had a positive SPT to cats. Of these 103 (23.4%) had a cat at home and 336 (76.6%) never had a cat in the house. With a greater positive cut-off(a wheal diameter > or =4 mm) 140 (2.8%) showed a positive SPT to cats of these 35 (25%) had a cat at home and 105 (75%) had only an indirect exposure to the pet. Of the telephone interviewed families; 16% stated they had a cat at home. Cat sensitivity is less prevalent in Italy, in this hospital based population, compared with other European countries and this is in agreement with a lower rate of cat ownership. Cat sensitivity was three times more frequent in children who never had a cat at home, than in children living with cats, when the selected positive cut-off was either a wheal diameter of 3 mm or > or =4 mm. Thus in a population with a low prevalence of cat ownership public exposure seems to be more important than domestic exposure for the development of sensitivity.