Case Presentation: A 25-year-old African American male with no significant medical history presented to the hospital with a new-onset skin rash. Over a month, he noticed a migratory pruritic rash growing on his trunk, arms and legs. He also experienced intermittent high-grade fevers, sore throat, and diffuse symmetrical joint pain. On arrival, patient was noted to have a fever over 104 °F. Physical examination revealed hyperpigmented lichenoid papules coalescing into plaques (figure 1). Laboratory evaluation revealed elevated acute phase reactants with ESR at 110 mm/hr, CRP at 95 mg/L, and ferritin at 33,000 ng/ml. He was also found to have leukocytosis and a mild increase in liver enzymes. Rheumatologic serologies and autoimmune panel for vasculitis only revealed a weakly positive antinuclear antibody. Infectious workup including blood culture, HIV, RPR, Chlamydia/Gonorrhea NAAT, anti-DNAse B, ASO, Hepatitis panel, EBV IgM, Parvovirus IgM, Lyme total AB, and Quantiferon gold were negative. CT of the neck showed several enlarged lymph nodes bilaterally, which were presumably reactive in etiology. TTE was also performed to rule out endocarditis and had no significant findings. Finally, a skin biopsy was obtained which revealed mild perivascular inflammation and dyskeratotic cells. Our patient was diagnosed with Adult-Onset Still’s disease using Yamushi criteria (figure 2). He was started on indomethacin 50mg TID and discharged home with close outpatient follow-up.

Discussion: Adult-Onset Still’s Disease (AOSD) is a rare systemic inflammatory disease, with only a few cases reported in the black community [1, 2]. The diagnosis of AOSD can be challenging as it presents with nonspecific systemic symptoms, and there are no characteristic serological biomarkers [3]. Several sets of classification criteria have been introduced, among which Yamaguchi criteria are the most commonly used [3]. One major criterion is the presence of a transient nonpruritic maculopapular salmon-colored rash, which often occurs along with febrile events [2, 3]. However, there have been reports of atypical cutaneous manifestations, such as the development of hyperpigmented plaques or urticarial-like eruptions [1, 4]. For this reason, it is fundamental for physicians to consider different presentations to prevent the delay of diagnosis and start early treatment [1-3].

Conclusions: In conclusion, AOSD may present with atypical cutaneous manifestations and can occur in the black population [1,2]. Recognition of these clinical variants is crucial for the early diagnosis of AOSD.

IMAGE 1: Picture of Patient’s Rash

IMAGE 2: Yamagushi Criteria