Failure of omalizumab (Xolair®) in the treatment of a case of solar urticaria caused by ultraviolet A and visible light.

Solar urticaria is a rare photodermatosis probably caused by a chromophore, that - if activated by light of a specific spectrum - binds to mast cell-bound IgE and elicits degranulation. In our patient an action spectrum in ultraviolet A and visible light range was found, in the autologous serum test the presence of a serum chromophore for the same action spectra could be demonstrated, which may underline this pathogenetic hypothesis. Symptoms did not improve using antihistamines and sun protection. Photo hardening was denied from the patient, immunosuppression and plasmapheresis were discussed but not considered. So a treatment with Omalizumab was started that recently was successfully used in 4 case reports. After 3 doses of Xolair® there was no changing in the phototesting results and after 4 doses no subjective improvement.