Pos1182 Characteristics of Adult-Onset Still’s Disease Skin Eruption in Individuals of African Ancestry

Background: Adult-onset Still's disease (AOSD) can manifest as a febrile eruption of various presentations, and some studies suggest that presence of a so-called atypical rash may be associated with a worse disease course in patients of Caucasian or Asian origin. However, nothing is known about AOSD eruption in individuals of African ancestry, from its basic description to its potential clinical implications. Objectives: To describe the AOSD eruptions in individuals from the Caribbean island of Martinique, and to compare patient characteristics and outcomes according to eruption pattern. Methods: We conducted a population-based retrospective study in tertiary center Martinique between 2004 and 2022. Patients were included if they were 16 years of age or older, of African descent and followed up for AOSD. Typical eruption was defined as salmon-pink, non-pruritic, evanescent macules and/or papules. Atypical eruption was defined as any skin symptomatology not meeting the definition of typical eruption, with the exception of the colour criterion. Systemic pattern of AOSD was defined as monocyclic with a unique flare followed by remission or polycyclic with first flare followed by one or more relapses, whereas the chronic articular pattern of AOSD was defined as a disease with predominant joint involvement. Localisation, time of appearance, skin histopathology, clinical and biological data, complications and treatment were collected and compared between groups. Results: Thirty-three patients were identified and 29 patients (76% women) with a median age of 35.6 years [27.3; 59.4] had an eruption and were included. 21 (72.4%) patients had atypical eruption with the following characteristics: persistent (n=8; 38%), pruritic (n=17; 80.9%), urticarial (n=8; 38%), eczematous (n=1; 4.8%), plaques (n=8; 38%), patches (n=6; 28.6%), bullae (n=1; 4.8%), and erythroderma, erosion, scales, purpura and necrosis (n=2; 9.5% each). 14 (66.6%) patients presented both typical and atypical AOSD eruption. Typical and atypical eruptions were mainly located on the chest (43% and 58%, respectively) and lower limbs (43% and 53%, respectively). Histopathology was not specific with oedema and inflammatory infiltrate of lymphocytic cells or neutrophils. Patients with an atypical rash had predominantly a systemic polycyclic pattern (47.6%), and patients with a typical rash only predominantly had a monocyclic pattern (75%) (p=0.08). Ten (47.6%) and 6 (28.6%) patients with atypical skin eruption and 6 (75%) and 1 (12.5%) patients with typical skin eruption developed, pulmonary and cardiac involvement, respectively, with no statistical difference. However, patient with atypical rash significantly had higher SGOT (p=0.0143) and SGPT (p=0.003) and received more methotrexate (p=0.007) and anti-IL1 therapy (p=0.038) than those with typical eruption. Finally, 3 (14.3%) macrophage activating syndrome and 2 deaths (9.5%) occurred, exclusively in patients with atypical skin eruption. Conclusion: Atypical eruption is predominant in our Caribbean population of African descent with AOSD. It might be associated with a more severe systemic phenotype and worse outcomes but more data are needed. REFERENCES: [1] De Fritsch E, et al. Epidemiology, characteristics, treatments, and outcomes of adult-onset Still's disease in Afro-Caribbeans: Results from a population-based study in Martinique, French West Indies. J Autoimmun. 2023 [2] Zuelgaray E, et al. Increased severity and epidermal alterations in persistent versus evanescent skin lesions in adult-onset Still disease. J Am Acad Dermatol. 2018 [3] Gerfaud-Valentin M, et al. Adult-onset Still's disease. Autoimmun Rev. 2014 Acknowledgements: NIL. Disclosure of Interests: None declared.