Off-label omalizumab use in a child with chronic spontaneous urticaria

An eight-year-old boy presented with migratory maculopapular skin lesions – evolving over eight weeks. 

On examination, the lesions were erythematous, non-ecchymotic, pruritic, and some lasted more than 24 hours. He patient also exhibited arthralgias in the shoulders, wrists, knees, and tibiotarsal joints, along with conjunctival hyperemia. 

The child was prescribed oral betamethasone (0.03 mg/kg/day) and bilastine (10 mg twice daily) for four weeks. This treatment successfully resolved his arthralgias and conjunctival hyperemia but did not improve the skin lesions. 

Urticarial vasculitis was suspected, prompting a multidisciplinary approach with Allergy and Clinical Immunology. Comprehensive blood tests, including – complete blood count, biochemistry, C-reactive protein, erythrocyte sedimentation rate, thyroid function, antinuclear antibodies, complement fractions, serum immunofixation, cytomegalovirus, and Epstein-Barr serologies, were unremarkable. His total serum immunoglobulin E (IgE) level was 151 IU/mL.

Betamethasone was discontinued, and the antihistamine dose was quadrupled to prepare for a skin biopsy. The biopsy, performed after a week without corticosteroids, showed findings consistent with urticaria, excluding vasculitis. 

Systemic corticosteroids were restarted for uncontrolled chronic urticaria (UAS7 >31 points and C-DLQI 29 points). After five months and multiple unsuccessful attempts to taper corticosteroids, the patient developed side effects, including 11% weight gain, hirsutism, cushingoid facies, and asthenia.

Cyclosporine (3 mg/kg/day) was introduced alongside a quadruple dose of bilastine, but after four weeks, there was no improvement. The boy began to experience bullying and depressive symptoms.

Due to the refractory skin lesions and their impact on his quality of life, omalizumab (300 mg subcutaneously every four weeks) was added. Skin lesions improved after the first administration, allowing corticosteroid discontinuation after one month. Complete clinical resolution was achieved after the third administration, and omalizumab dosing was eventually extended to every eight weeks. 

After 15 months of treatment, the child reported numbness in the left leg, along with knee and foot pain. Comprehensive blood tests were normal, and Rheumatology consultation ruled out arthritis. The omalizumab dose was reduced to 150 mg every eight weeks, resolving the numbness and joint pain.

After 22 months of omalizumab treatment, the child remained in clinical remission with no adverse effects. 

Omalizumab can be an effective and safe treatment for antihistamine-refractory chronic spontaneous urticaria (CSU) in children – enabling discontinuation of immunosuppressive therapy and improving quality of life. Further studies are needed to determine the minimum effective dose and duration of treatment in children under 12 years of age.

Source: Gonçalves T, Coutinho IA, Pita JS, et al. Nascer e Crescer. 2024 Mar;33(1):51-5.