Drug eruption by antihistamine mistaken for chronic urticaria in a child

Although rare, antihistamines can cause adverse effects, including drug-induced eruptions or anaphylaxis. A 4-year-old child visited the pediatric department of a hospital for skin eruptions after administration of antihistamines, (e.g., ucerax [hydroxyzine] or leptizine [levocetirizine]), for cholinergic rashes; he did not have pruritus. Skin prick, intradermal, and drug provocation tests were performed to determine the relationship between the antihistamines and eruptions. Levocetirizine induced wheals in the skin prick test and a rash in the oral drug provocation test. In contrast, ketotifen induced no reaction in the skin prick test but showed a positive reaction in the oral provocation test. Our case report highlights that children can experience the same types of adverse reactions as seen in adults, and cross-reactivity between various antihistamines can occur.