Cureus Case Study: Omalizumab Treats Exercise Urticaria

A 23-year-old female patient experienced the complete resolution of exercise-induced urticaria and angioedema after beginning monthly injections of omalizumab, Cureus reported in a detailed case study documenting a complex overlap of exercise-triggered allergic syndromes. The patient initially presented with symptoms including peri-orbital angioedema, wheeze, cough, and widespread hives during intense physical exertion such as running, which required multiple adjustments by allergy and immunology specialists over several years.

The Diagnostic Overlap Between Exercise-Induced Anaphylaxis and Cholinergic Urticaria

Symptoms first began in 2018, typically starting with scalp pruritus before progressing to lower limb urticaria at clothing contact sites and spreading to uncovered areas like the face. The clinical presentation illustrated a distinct diagnostic overlap between exercise-induced anaphylaxis, a rare and life-threatening syndrome, and cholinergic urticaria, which is a form of chronic inducible urticaria triggered by rises in core body temperature. The patient also reported passive heating triggers such as hot showers and hot tubs, emotional states like anger and embarrassment, and positive dermatographia testing during clinical assessments.

Past medical history revealed pre-existing exercise-induced bronchoconstriction, eczema, and seasonal allergies. While skin-prick and specific IgE testing for food allergens were consistently negative, the patient demonstrated specific sensitisation to house dust mite, animal dander, and several mould species. Baseline serum tryptase tested in 2023 measured 4.7 micrograms per liter, which remained well within the normal reference range of under 10 micrograms per liter, while serum total IgE was elevated at 516 kU/L against a reference range under 214 kU/L.

Escalating Antihistamine Treatments and Subsequent Biologic Therapy

Initial treatment in 2018 involved oral levocetirizine at 5 milligrams twice daily, famotidine at 20 milligrams before exercise, and as-needed inhaled albuterol for exercise-induced bronchoconstriction. By 2020, refractory symptoms prompted clinicians to increase famotidine to 12-hourly dosing on exercise days and double levocetirizine to 10 milligrams every 12 hours. Patient-reported sedation necessitated switching to fexofenadine at 180 milligrams twice daily, and a leukotriene receptor antagonist, montelukast at 10 milligrams daily, was added during a 2022 reassessment.

Because symptoms persisted despite high-dose antihistamines and montelukast, treating physicians proposed omalizumab. Initiated in 2023 as monthly 300-milligram injections, the monoclonal antibody treatment successfully resolved the exercise-induced urticaria and angioedema. Omalizumab functions by preventing free IgE from binding to high-affinity IgE receptors on mast cells and basophils, offering relief for patients with antihistamine-refractory chronic inducible urticaria and exercise-induced reactions.

Long-Term Management and Physical Activity Maintenance

By 2026, eight years after the initial onset of her condition, the patient maintained stable symptom control using a regimen of four-weekly omalizumab 300-milligram injections, daily montelukast, and fexofenadine taken one hour prior to physical activity. High ambient temperatures are now tolerated without adverse reactions, and while vigorous cardiovascular exercise is avoided, physical activity is maintained safely through low-to-moderate intensity routines. Careful symptom monitoring and prompt cessation of exertion at the earliest warning signs have ensured that epinephrine autoinjector use has not been required.