Abstract

Schnitzler syndrome is a very rare autoimmune condition with about 300 reported cases. We report a case of a 61 year-old male that presented with a 5-year history of chronic urticaria and later manifested musculoskeletal pain and fevers which were temporally-related to the patient’s urticaria. On clinical examination, the patient was ill-appearing and had generalized erythematous, edematous, pruritic papules. He was unable to sit upright secondary to pain. Punch biopsy was obtained and histologic examination revealed orthokeratosis overlying an unremarkable epidermis. The underlying dermis demonstrated a superficial and deep perivascular lymphocytic predominant inflammatory infiltrate with interstitial neutrophils and rare eosinophils. Laboratory examination revealed a markedly elevated erythrocyte sedimentation rate and C-reactive protein. Protein electrophoresis demonstrated an IgM kappa restricted monoclonal gammopathy, and a bone marrow biopsy confirmed a monoclonal gammopathy of undetermined significance. Given the clinical and histologic features, a diagnosis of Schnitzler syndrome was rendered.  Schnitzler syndrome was originally described by Dr. Liliane Schnitzler in 1972 as an auto-inflammatory disease of adult-onset. The diagnosis is made based on the Lipsker or Strasbourg criterias, both of which require the presence of an urticarial rash and monoclonal IgM or IgG with two to three additional minor criteria. The Strasbourg criteria includes a distinct requirement of the presence of a neutrophilic dermal infiltrate with leukocytoclasia but without vasculitis and edema. We present this case to bring awareness to a rare entity. As the histology in Schnitzler syndrome is non-specific, clinicians must maintain a high index of suspicion to render an accurate diagnosis.