Foreign body reaction involving a Mantoux test site.

A 41-year-old woman presented with a history of a solitary pustular erythematous lesion occurring at the site of a Mantoux test performed 10 months previously. The histopathology examination revealed a suppurative and foreign body giant cell reaction to numerous keratin flakes. Culture of the tissue was negative for both aerobic and anaerobic organisms including mycobacteria. We postulate that the reaction in our patient may have been secondary to the implantation of epidermal keratin or the entrapment of hair into the dermis during the intradermal injection of tuberculin purified protein derivative.