Inflamed psoriatic plaques: Drug toxicity or disease exacerbation?
A 50-year-old HIV negative male with plaque psoriasis involving 45% of the patient's total body surface area with a Psoriasis Area Severity Index (PASI) score of 17 was administered 7.5 mg methotrexate weekly orally after the recommended baseline investigations were carried out. A week later, there was increased activity of the lesions, with signs of increased inflammation. Dose of methotrexate was increased to 10 mg per week after repeating routine recommended investigations. Two weeks later patient came back with extremely painful superficial erosions of the pre-existing psoriatic plaques [Figures , ] along with history of headache, blurring of vision, and diarrhea.\nOn examination, the patient was conscious and normotensive. Cutaneous examination revealed intense erythema and erosions over the pre-existing psoriatic plaques [Figures , ], facial and palmar erythema [Figures , ], and mucositis. Systemic examination was otherwise normal. Laboratory studies revealed a hemoglobin of 11.2 g/dL, red blood cell count of 4.45 lakhs/μL, mean corpuscular volume of 96 fL, white blood cell count (WBC) of 5500/μL, and platelet count of 2,60,000/μL. Serum biochemistry showed a serum creatinine level of 0.8 mg/dL, blood urea nitrogen 35.0 mg/dL, total bilirubin 0.4 mg/dL, serum glutamate oxaloacetate transaminase (SGOT) 27 IU/L, serum glutamate pyruvate transaminase (SGPT) 25 IU/L, and alkaline phosphatase 113 IU/L. Prothrombin time and partial thromboplastin time were within normal limits. Urine and stool analysis, chest X-ray, and electrocardiogram were normal. Blood culture was sterile and there was no other evidence of systemic infection. Serum concentrations of methotrexate and metabolites were not measured due to limited resources.\nThough the baseline investigations at first and subsequent visits (7 and 14 days) were within normal limits, based on the clinical features, a possibility of methotrexate toxicity was considered. The patient was inappropriately self-administering 10 mg methotrexate daily orally. He was given injection leucovorin calcium 20 mg IV stat at the time of presentation. In view of normal hematological and biochemical parameters, further doses of leucovorin were not given. Further doses of methotrexate were withheld and simultaneously topical steroids (fluticasone propionate cream 0.05%) and oral antihistaminics (cetrizine) were administered, which resulted in dramatic improvement of the cutaneous lesions within 7 days and complete healing in 14 days [Figures -].