SEVERE ATOPIC DERMATITIS IMPROVED WITH OMALIZUMAB TREATMENT OF CHOLINERGIC URTICARIA

Abstract

<h3>Introduction</h3> Interrupting the itch-scratch cycle can be key to managing atopic dermatitis (AD). We present a patient with severe AD who improved with omalizumab treatment of coexistent cholinergic urticaria (CholU). <h3>Case Description</h3> A 17-year-old girl with longstanding AD, on dupilumab for two years, presented for recurrent hives and anaphylaxis. Patient's mother described several episodes of itching, small wheals, and "fainting" over the previous 18 months. All episodes occurred when the patient was "feeling hot" and had been engaged either in strenuous physical exertion or light exertion in heat. With one episode, she received intramuscular epinephrine and returned to baseline; others resolved after cooling. Her AD control had deteriorated since episodes began. CholU was considered in the differential. After four months of daily second-generation antihistamine, she reported worsening eczema and no change in urticaria/anaphylaxis episodes. Urticaria treatment was escalated to maximal daily doses of fexofenadine, famotidine, and montelukast, with minimal improvement. She underwent provocation skin testing with methacholine, off antihistamines. Histamine prick was positive with wheal/flare of 7/26mm. Methacholine intradermal tests were positive at two concentrations: 0.1 mg/ml (5/13mm) and 1.0 mg/ml (8/20mm). Intradermal saline control was non-reactive. CholU was definitively diagnosed. The patient stopped dupilumab and initiated omalizumab 300 mg every four weeks. Her urticaria and eczema improved dramatically, and she had no further anaphylaxis. <h3>Discussion</h3> CholU is a type of urticaria induced by increase in core body temperature. Anaphylaxis may occur in advanced cases. In patients unresponsive to antihistamines, omalizumab has proven effective.