Allergy skin prick testing is regarded as a routine diagnostic procedure in hospital settings, but its role in general practice is not yet defined. Our aim was to explore the ways in which skin prick testing might facilitate the work of general practice nurses engaged in asthma patient care. A structured questionnaire was completed by 18 practice nurses before and again after administering allergy skin tests to four common aeroallergens (dust mite, grass pollen, cat and dog danders) to 319 consecutive attenders with known or suspected asthma. Nurses' decisions about whether or not to give allergen avoidance advice were reversed after skin testing in 63 (22%) cases for dust mite, 67 (23%) cases for grass pollen, 38 (13%) cases for cat fur and 49 (17%) cases for dog hair. Had allergen avoidance interventions been targeted only at patients with both a positive skin test and a positive clinical history, the number of planned interventions would have declined from 305 before skin testing to 142 after. The findings suggest that allergy skin prick testing was feasible and acceptable in general practice, and that one role may be to reduce the number of allergen avoidance interventions offered to patients unlikely to benefit.