Leprosy in a rheumatology setting: a challenging mimic to expose
A 52-year-old woman presented with painful rapidly progressive symmetrical polyarthritis of about 4 months in duration, without any extra-articular features, and was diagnosed with clinical RA. She was grossly limited in her daily activities and complained of prolonged morning stiffness. Other than symptomatic treatment, she also begun on oral daily administration of 10 mg leflunomide and 5 mg prednisolone. She was also on regular supervised medication for diabetes, hypertension, and epilepsy. On questioning, she recalled a history suggestive of suffering from leprosy (?polyneuritic) along with pulmonary tuberculosis several years ago and receiving prolonged therapy for about 18 months.\nTwo months later, she developed erythematous scaly macular rash on the back and lower limbs along with small ulcers on both soles. The arthritis was almost settled, and minimal tenderness elicited in the wrists and small joints of the hands. Her ankles and feet looked somewhat puffy. She complained of numbness and abnormal feeling in the feet and lower part of the legs. Neurological examination showed wasting of thigh muscles and hyperesthesia in the upper and lower limbs. She did not have any other systemic abnormality. Laboratory investigations showed a near normal hemogram with elevated CRP and seronegative for RF, ANA, and anti-CCP. Metabolic and hepatic parameters were normal, but renal functions were mildly deranged with elevated serum creatinine. Her serum uric acid was grossly elevated at 12.0 mg/dl (lab normal <7 mg/dl). X-ray of the hands showed juxta-articular osteoporosis and erosions typical of RA. Ultrasonography of the abdomen and pelvis showed mild hepatomegaly only. She was further investigated by a dermatologist who opined that the current complication was an activation of old leprosy in the form of probable lepra reaction, but a close differential of an adverse event due to leflunomide was also considered; skin clip was negative for AFB. The antiarthritis medication was changed to only symptomatic drugs, and anti-leprosy drugs were added and continued with low-dose orally given prednisolone. Six months later, she improved considerably with healed skin lesion, minimal numbness in the extremities, and absence of arthritis.