Isoniazid induced palmoplantar hyperhidrosis.

Secondary focal hyperhidrosis is usually due to peripheral or central neuronal defects and is a complex dysfunction of the parasympathetic and sympathetic nervous system. Palmoplantar hyperhidrosis has been described with various types of polyneuropathies such as diabetic but has not previously been described with isoniazid. We report a 15-year-old boy, being followed for neurotuberculosis, who presented with burning sensation and hyperhidrosis of both palms and soles five months after starting antitubercular therapy. With oral pyridoxine supplementation, the paraesthesia and hyperhidrosis reduced to minimal severity over the next four months. Before commencing antiperspirants, simple pyridoxine supplementation can lead to the reversal of symptoms in such cases.