Resumen

Objectives: The main objectives of this case report are to present the clinical presentation and diagnosis of Urticaria Pigmentosa, recognize the role of multidisciplinary evaluation in ruling out systemic involvement, and critically assess the variable efficacy of subcutaneous Omalizumab in refractory cases. Introduction: INTRODUCTION: Urticaria Pigmentosa is a subtype of cutaneous mastocytosis, a rare condition characterized by an abnormal proliferation of mast cells in one or more organs. It is often linked to mutations in c-kit gene. The disease presents a clinical spectrum, ranging from mild skin manifestations to systemic involvement, particularly in adults. Omalizumab, a monoclonal antibody targeting immunoglobulin E (IgE), has shown potential in managing symptoms that are refractory to conventional treatment, with large cohort studies reporting a 76.8% overall response rate. Materials / method: CASE REPORT: This is a case of a 40-year-old Filipino male who presented with 8 year-history of generalized tan to hyperpigmented macules and papules. Symptoms included severe pruritus and wheal formation triggered by scratching, friction, and humid weather. Baseline laboratories were normal. Skin biopsy showed numerous mast cells, with positive CD117 and Giemsa stains confirming the diagnosis of Urticaria Pigmentosa. Results: The patient was referred to hematology and gastroenterology, where systemic involvement was ruled out. Oral antihistamines and topical mid-potent corticosteroids were initiated which halted the pruritus and progression of lesions, however, still with recurrence. The patient received two doses of subcutaneous Omalizumab (150 mg/vial) at 4-week intervals over 12 weeks with no reported adverse events. Response was monitored overtime, however, no significant improvement was reported in terms of pruritus, flare reduction or the number of lesions. Conclusion: CONCLUSION: Urticaria Pigmentosa follows a chronic course and requires periodic monitoring. The primary treatment goal focuses on trigger avoidance and symptomatic control. A multidisciplinary approach is essential to confirm the absence of systemic involvement. Based on systematic reviews and several case studies, Omalizumab demonstrates promising results as a therapeutic option for refractory cases; however, clinical outcomes continue to vary among patients. Therefore, additional clinical trials are necessary to further evaluate its efficacy.