Isoniazid-induced Alopecia: A Rare Entity

As per the global tuberculosis (TB) report 2018; the estimated incidence TB in India was approximately 2,800,000 cases accounting for about one-fourth of global TB burden. 1 Isonicotinic acid hydrazide (INH) or simply isoniazid is a drug used in the treatment and prevention of TB. It is one of the most important drugs in the therapy of TB and was introduced into the treatment regimen in 1952. It is usually administered orally, but can be given as injection. Isoniazid is commonly used in combination with other drugs, such as rifampicin, ethambutol, pyrazinamide and streptomycin. These drugs are used with isoniazid in order to prevent, or delay, the development of isoniazid-resistant strains of Mycobacterium tuberculosis. The side effects of INH include hepatitis (especially in older patients), peripheral neuropathy (dose related incidence; 10%-20% incidence with 10mg/kg/day), loss of appetite, vomiting, abdominal pain, dizziness or weakness, and headache. 2 To the best of our knowledge, there are limited reports describing temporal association of isoniazid with alopecia. We report one such rare case presenting with hair loss after initiation of antitubercular treatment due to isoniazid.