Case presentation
A 51-year-old Sudanese female was diagnosed with RA in 2018 based on the EULAR classification of RA. She had a history of bilateral symmetrical polyarthritis with involvement of small joints of the hands, both wrists and shoulders; they are also associated with morning stiffness lasting for two hours. She was treated successfully with methotrexate and prednisolone and her disease remains in remission. A year ago, she started to develop an itchy skin rash with pus involving her lower extremities and abdomen. She had no fever, weight loss, skin rashes, bowel symptoms, aphthous ulcers or hair loss. Currently, she has no joint pain or extra-articular manifestations. Her systemic review was unremarkable. The patient had hypertension for 5 years, her family history revealed no history of connective tissue diseases. She is a mother of 7 healthy children with no history of abortion. In terms of drug history, she is on amlodipine 5 mg for hypertension. Her musculoskeletal examination showed no synovitis, her skin examination showed nodulopapular lesions affecting the extensor surfaces of the lower extremities particularly on thighs and the lower part of the abdomen with hyperpigmentation as shown in the figures (1, 2). Laboratory tests revealed normal liver function test and renal function test, C-reactive protein 12.9 (<5), Erythrocyte sedimentation rate (ESR) is 70mm/hr (<15), normal urine analysis and blood sugar level 98 mg/dl. With regards to Immunological studies: Rheumatoid factor (RF) <8 (negative), anti-citrullinated peptide antibodies (ACPA) <4(<20, negative) and Antinuclear factor <1/80(negative). Hand X-ray demonstrated periarticular osteopenia and the Chest x-ray was normal. Skin lesion biopsy showed multiple foci of necrosis, mixed inflammatory infiltrates composed mainly of neutrophils, hyperkeratosis and acanthosis and no evidence of vasculitis. The biopsy findings were consistent with a diagnosis of neutrophilic dermatosis fig (3, 4). The patient received topical and systemic steroids for the skin lesion however, no significant improvement was noticed, and then she was started on cyclosporin 100 mg twice a day with close monitoring of the serum creatinine and blood pressure, few weeks later her skin lesions and general condition showed marked improvement.