Rifamycin induced leukocytoclastic vasculitis. A rare side-effect of anti-tuberculous chemotherapy

Cutaneous adverse reactions to anti-tuberculous medications are known to affect up to 5% of patients 1 . The most common causative agent is pyrazinamide. Reactions to rifamycins are rare affecting only 1% of patients 1 . We describe a case of leucocytoclastic vasculitis (LCV) caused by rifamycins. A 53 year old female presented with cough, night sweats and upper lobe nodules. Bronchial-alveolar lavage confirmed fully sensitive mycobacterium tuberculosis (TB). She commenced treatment with rifampicin, isoniazid, ethambutol and pyrizinazmide. At 4 weeks she developed an extensive purpuric rash, malaise and joint aches. There was no evidence of other infections or connective tissue disorders on extensive screening. Her inflammatory markers were elevated. A punch biopsy of her shin demonstrated leukocytoclastic vasculitis of the superficial dermis. All TB medications were discontinuted and she started oral steroids. The rash resolved within 2 weeks. She started Moxifloxacin, Isoniazid and Ethambutol without complication. After 1 week Rifabutin was introduced. This led to recurrence of the rash. Rifabutin was stopped; the rash resolved and inflammatory markers normalised. She continues on an 18 month course of Moxifloxacin, Isoniazid and Ethambutol. Leukocytoclastic vasculitis (LCV) is a hypersensitivity vasculitis characterised by small vessel damage by nuclear debris from invading neutrophils. It typically affects the skin and joints and can be precipitated by medications and infections 2 . This case illustrates that clinicians should be aware LCV is a rare side affect of Rifamycins. 1. Kim JH et al. Allergy Asthma Immunol Res. 2010 Jan; 2(1): 55–58. 2. Brooke A et al. Medscape Drugs and Diseases.