LAUSR

Importance Catastrophic antiphospholipid syndrome (CAPS) is a severe, rare complication of antiphospholipid syndrome (APS), but cutaneous involvement has not yet been adequately described. Objective To describe cutaneous involvement during CAPS, its clinical and pathological features, and outcomes. Design, Setting, and Participants This cohort study was a retrospective analysis of patients included in the French multicenter APS/systemic lupus erythematosus register (ClinicalTrials.gov: NCT02782039) by December 2020. All patients meeting the revised international classification criteria for CAPS were included, and patients with cutaneous manifestations were analyzed more specifically. Main Outcomes and Measures Clinical and pathological data as well as course and outcome in patients with cutaneous involvement during CAPS were collected and compared with those in the register without cutaneous involvement. Results Among 120 patients with at least 1 CAPS episode, the 65 (54%) with skin involvement (43 [66%] women; median [range] age, 31 [12-69] years) were analyzed. Catastrophic antiphospholipid syndrome was the first APS manifestation for 21 of 60 (35%) patients with available data. The main lesions were recent-onset or newly worsened livedo racemosa (n = 29, 45%), necrotic and/or ulcerated lesions (n = 27, 42%), subungual splinter hemorrhages (n = 19, 29%), apparent distal inflammatory edema (reddened and warm hands, feet, or face) (n = 15, 23%), and/or vascular purpura (n = 9, 14%). Sixteen biopsies performed during CAPS episodes were reviewed and showed microthrombi of dermal capillaries in 15 patients (94%). These lesions healed without sequelae in slightly more than 90% (58 of 64) of patients. Patients with cutaneous involvement showed a trend toward more frequent histologically proven CAPS (37% vs 24%, P = .16) than those without such involvement, while mortality did not differ significantly between the groups (respectively, 5% vs 9%, P = .47). Conclusions and Relevance In this cohort study, half the patients with CAPS showed cutaneous involvement, with a wide spectrum of clinical presentations, including distal inflammatory edema. Skin biopsies confirmed the diagnosis in all but 1 biopsied patient.