DP24 An unusual case of drug-induced annular granulomatous vasculitis in a patient with rheumatoid arthritis and type 2 diabetes mellitus
Authors: Kubba Faris , Aliyeva-Derraz Pakiza , Gradassi Alessandro Traniello 
Published: June 2024

Abstract
A 61-year-old Asian woman presented with acute onset of a widespread rash and 3–4-cm infiltrated erythematous plaques in the arms, legs and torso, with a few showing an annular configuration soon after he had taken naproxen for rheumatoid arthritis. After 48 h the plaques had developed into purpura and petechiae. Past medical history also included diabetes mellitus type 2, hypertension, left knee replacement, cauda equina syndrome and asthma. Her medications comprised losartan, atorvastatin, metformin, amlodipine and naproxen. The differential diagnosis included sarcoidosis, Wells syndrome, panniculitis and vasculitis. Histopathology of the 4-mm punch biopsy from the right flank showed mild spongiosis, focal lymphocyte exocytosis, focal basal vacuolar degeneration, superficial dermal oedema, mild superficial and deep dermal perivascular and perisudoral lymphocytic infiltrate with neutrophilic microabscesses, and leucocytoclasia associated with small histiocytic aggregates. Focal involvement of the subcutis was also present. No obvious collagen necrobiosis with histiocyte palisading, flame figures or increased eosinophils were seen. No medium vessel vasculitis was identified. Periodic acid–Schiff stain was negative for fungi, and Ziehl–Neelsen stain did not reveal acid-fast bacilli. Both vasculitis and viral screens were normal apart from elevated D-dimers, serum ferritin and positive Epstein–Barr virus DNA. Our working diagnosis was a neutrophilic and histiocytic dermatosis with leucocytoclastic vasculitis. Given the history of rheumatoid arthritis, a palisading neutrophilic granulomatous dermatitis was also considered, as the findings may vary according to the age of the lesion. However, the findings were best fitted to a vasculitic granulomatous drug reaction as there were focal vacuolar interface changes and obvious lymphocyte epidermotropism involving the entire epidermal thickness. There was no resemblance to other conditions like rheumatoid nodule, interstitial granuloma annulare or infective necrotizing granulomas. In their recent review, Shah et al. identified five patterns of drug-induced granulomatous dermatosis (Shah N, Shah M, Drucker AM et al. Granulomatous cutaneous drug eruptions: a systematic review. Am J Clin Dermatol 2021; 22: 39–53). They included (i) interstitial granulomatous drug reaction, (ii) drug-induced accelerated rheumatoid nodulosis, (iii) drug-induced granuloma annulare, (iv) drug-induced sarcoidosis and (v) miscellaneous presentations. The authors also concluded that polypharmacy and a prolonged lag period from drug intake to lesion onset would result in diagnostic challenges, as in our case. On suspension of naproxen, the rash had subsided and it resolved 2 weeks later. We have presented the case of a 60-year-old patient with an unusual granulomatous neutrophilic dermatitis associated with leucocytoclastic vasculitis that did not fit with the usual patterns described in association with rheumatoid arthritis. The final diagnosis was a vasculitic granulomatous drug reaction, secondary to naproxen, as suggested by the presence of epidermal changes and absence of significant systemic symptoms. Knowledge of this entity is helpful to distinguish these lesions from palisading neutrophilic granulomatous dermatitis and from other similar dermatosis. The lesions should resolve with discontinuation of the causative drug.