OMALIZUMAB: A POTENTIAL LONG-TERM THERAPEUTIC ALTERNATIVE FOR REFRACTORY DELAYED PRESSURE URTICARIA?

Abstract

<h3>Introduction</h3> Delayed pressure urticaria (DPU) can go unrecognized due to its delayed onset. While most are antihistamine resistant, this case illustrates a complete response to omalizumab as a potential long-term therapeutic alternative. <h3>Case Description</h3> A 44 year-old man who works at a weapons disposal arsenal presents for chronic spontaneous delayed pressure urticaria. Exam reveals lesions on his trunk and extremities with redness and oozing blisters. Triggers include using his hands, wearing a respirator backpack, or leaning against an object for longer than 5 minutes. Skin biopsy reveals nonspecific eosinophilic infiltrate and labs showed mildly elevated CRP. He is treated with cephalexin for presumed cellulitis and high dose antihistamines, famotidine, and montelukast without relief. Given recurrent episodes, the patient is started on monthly omalizumab with complete resolution after the first injection. <h3>Discussion</h3> DPU is a physical urticaria that presents with erythematous, pruritic painful swellings, occasionally with blisters, after prolonged pressure on the skin. The incidence is 2% and occurs in up to 37% of patients with chronic spontaneous urticaria (CSU). Pathophysiology is due to late phase reaction from mast cell activation and upregulation of E selectin leading to an inflammatory response with cytokines and cellular infiltrates. Management is generally unsatisfactory and consists mainly of antihistamine, NSAIDs, colchicine, TNF-a blocker, IVIG, and montelukast. Oral steroids are the most effective treatment, but should not be used long-term. This case illustrates a favorable response to omalizumab, normally used in CSU. Proposed mechanism in a bullous DPU case involves inhibition of cutaneous mast cells, resulting in decreased eosinophil degranulation.