A 58-year-old man is being evaluated for a 4-year history of a diffuse, intermittent, nonpruritic rash associated with intermittent arthralgia, myalgia, generalized lymphadenopathy, night sweats, and unintentional weight loss of 10 pounds over 8 months. The symptoms did not appear in a predictable pattern each day or week. The rash was not responsive to oral antihistamines. Laboratory tests over the 4 years showed persistent leukocytosis (range 13,000-20,200/μL[13.5-20.2×109/L]) with neutrophilia (range 11.2-17.3×103/μL [11.2-17.3 109/L]), worsening anemia (hemoglobin concentrations of 13.2-11.0 g/dL [132-110 g/L]), elevated erythrocyte sedimentation rate (92 mm/h), C-reactive protein (154 mg/L), and ferritin (494 ng/mL [494 μg/L]), and monoclonal IgM-κ gammopathy. Workup for Lyme disease, hepatitis B and C, HIV, tuberculosis, and syphilis was negative. Antinuclear antibody, anti–double- and single-stranded DNA, rheumatoid factor, anti-SSA, and anti-SSB were negative, and complement levels were within normal limits. Bone marrow and excisional lymph node biopsies were unrevealing. Physical examination revealed erythematous wheals coalescing into plaques scattered symmetrically on the trunk and extremities (Fig 1). A punch biopsy of the left arm was performed (Fig 2).Fig 2By Devea R. De, BS; Alicia Goldenberg, MD; Paul N. Bogner, MD; Susan Pei, MD, FAAD.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Question #1: What is the most likely diagnosis?A.Adult-onset Still disease (AOSD)B.Schnitzler syndrome (SS)C.Systemic lupus erythematosus (SLE)D.Cryopyrin-associated periodic syndromeE.Urticarial vasculitis Click here to view disclosures, take the quiz, and claim CME credit. The authors have no conflicts of interest to declare. Consent for the publication of recognizable photographs was provided by the authors at the time of article submission to the journal stating that all patients gave consent for their photographs to be published in print and online and with the understanding that these photographs may be publicly available.