Anaphylaxis to cat in a child with exclusive sensitivity to Fel d 1

Abstract

TO THE EDITOR: Allergy to dogs and cats is a widespread clinical problem, with cat allergies about twice as common as dog allergies. Cat allergen is more pervasive of the pet allergens and can be abundantly present even where a cat does not live. Much is known about allergic reactions to pets and especially cats, but, to the best of our knowledge, this is the first reported case of anaphylaxis after exposure to a cat. A 4-year-old boy was referred to our center for evaluation of systemic allergic reactions that occurred on 2 separate occasions after playing with a cat. On the first occasion, he developed hives, periorbital swelling, cough, and dyspnea with wheezing within minutes after contact with a cat at a friend’s house. Before the initial episode he was asymptomatic without prodromal illness. His symptoms completely resolved within 1 to 2 hours after receiving oral diphenhydramine by his parents. On the second cat exposure, his symptom onset was rapid and more severe, including generalized hives, marked difficulty breathing with wheezing, and abdominal pain, despite administering oral diphenhydramine (Figure 1). In view of the dramatic onset and severity of symptoms, anaphylaxis was suspected, although blood pressure was reported to be stable. While in the emergency department, he received intramuscular epinephrine,