Familial exercise-induced anaphylaxis.

We identified two siblings with exercise-induced anaphylaxis who share the HLA haplotype A3-B8-DR3 with their atopic father. The index case, a 16-year-old female, noted initial episodes at age 13. Intense pruritus, urticaria, facial edema, choking sensation, nausea, hypothermia, and collapse followed vigorous running but not swimming, cycling, racquetball, solar exposure, or cold exposure. Neither antihistamine, antiserotonin, anticholinergic nor epinephrine therapy was entirely effective or protective; only modification of running prevented episodes. Three similar episodes were noted at age 15 years by a brother who, now age 25, relates a 4-year history of seasonal rhinitis and exercise-related urticaria without anaphylactoid reaction. The remainder of the family (father, 47; mother, 46; brother, 22 years) does not have exercise intolerance. The father has allergic rhinitis; his nephew suffers exercise-induced urticaria without collapse. HLA typing revealed the father to be A1-B8-DR3, A3-B8-DR3; the symptomatic daughter to be A3-B8-DR3, A30-B5-DR8; and the symptomatic son to be A3-B8-DR3, A30-B5-DR8. The asymptomatic mother was A30-B5-DR8, A2-B7-DR5 and the asymptomatic son A1-B8-DR3, A30-B5-DR8. We describe exercise-induced anaphylaxis in a unique familial setting, perhaps linked to the HLA haplotype A3-B8-DR3.