Transient cutaneous hyperpigmentation of extremities following dengue fever

Abstract

A 14 year old boy presented with fever and generalized flushing of skin of 1 week duration. His vital signs were normal. Examination revealed generalized blanching macular erythematous rash. Systemic examination was unremarkable except for tender hepatomegaly. Investigations revealed leucopenia, thrombocytopenia and normal hemoglobin with mildly elevated liver transaminases. NS 1 (Non-structural protein-1) antigen and IgM antibody titer for Dengue ELISA was positive suggesting dengue fever. He was managed symptomatically and he recovered. During his follow up after 2 weeks he presented with brownish discoloration of dorsum of both hands and feet. There was no history of intake of any medication. Examination revealed symmetrical striking macular hyperpigmentation involving dorsum of extremities predominantly over the distal interphalangeal joints (Figs. 1, 2). His general physical and systemic examination was normal. His repeat blood counts, renal function tests, liver function tests and serum cortisol levels were normal. Vitamin B12 levels were normal and IgM antibody titre for chikungunya was negative. Workup for HIV and porphyria was negative. Parents were reassured and gradual disappearance of lesions was noticed over next 8 weeks. Cutaneous hyperpigmentation is known to be associated with a variety of systemic disorders which include endocrinapathies such as Addison’s disease, Nelson syndrome, metabolic diseases such as Wilson’s disease, Fanconi ‘s anemia, hemochromatosis and nutritional deficiencies mainly vitamin B12 [1]. Many drugs have been implicated in causing skin pigmentation including nonsteroidal anti-inflammatory drugs, antimalarials, amiodarone, cytotoxic drugs, and heavy metals [2]. Viral exanthematous illnesses are also known to cause hyperpigmented lesions, where etiology appears to be post inflammatory. Both diffuse and focal hyperpigmentation predominantly involving centrofacial area has been described in patients with chikungunya fever during the recovery phase [3]. TRANSIENT CUTANEOUS HYPERPIGMENTATION OF EXTREMITIES FOLLOWING DENGUE FEVER