Cutaneous Involvement in Catastrophic Antiphospholipid Syndrome in a Multicenter Cohort of 65 Patients

Key PointsQuestionWhat are the clinical and pathological features of cutaneous involvement during catastrophic antiphospholipid syndrome (CAPS)? FindingsIn this cohort study of 65 patients with skin involvement during CAPS, livedo racemosa, necrotic lesions, splinter hemorrhages, and vascular purpura, along with distal inflammatory edema, were observed. Skin biopsies showed microthromboses in 15 of 16 cases. MeaningCutaneous CAPS encompasses a wide spectrum of clinical features; skin biopsy is helpful as it may confirm microthrombosis in more than 90% of cases. ImportanceCatastrophic antiphospholipid syndrome (CAPS) is a severe, rare complication of antiphospholipid syndrome (APS), but cutaneous involvement has not yet been adequately described. ObjectiveTo describe cutaneous involvement during CAPS, its clinical and pathological features, and outcomes. Design, Setting, and ParticipantsThis 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 MeasuresClinical 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. ResultsAmong 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 RelevanceIn 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. This cohort study describes cutaneous involvement during catastrophic antiphospholipid syndrome, its clinical and pathological features, and outcomes.