Schnitzler syndrome is characterized by chronic urticaria, fever, arthralgia and/or bone pain, and IgM gammopathy. Other symptoms include lymphadenopathy, hepatosplenomegaly, and hyperostosis.1 Fewer than 50 cases have been reported to date. This chronic condition is typically unresponsive to antihistamine therapy and responsive to steroids. The prognosis is good, especially with respect to the bone pain, but not for the urticaria, which is resistant to all therapies. Colchicine, histamine1 (H1)- and histamine2-blockers, sulfones, chlorambucil, chloroquine, cyclophosphamide, azathioprine, and high doses of intravenous immunoglobulins were all ineffective. Only steroids work well, but long-term administration is followed by serious adverse effects. Modiano and colleagues2 reported a case with rapid regression of the cutaneous symptoms after psoralen–UV-A (PUVA) therapy. Recently, Gallo et al3 reported a case with an 85% improvement after a course of narrow-band UV-B phototherapy with immediate relapse after cessation of treatment.
Cianchini G, Colonna L, Bergamo F, Angelo C, Puddu P. Efficacy of Psoralen–UV-A Therapy in 3 Cases of Schnitzler Syndrome. Arch Dermatol. 2001;137(11):1536-1537. doi: