Old tuberculin

Mammalian tuberculin purified protein derivative (tuberculin PPD) is the active principle of old tuberculin. A small test dose in a healthy individual, given intracutaneously, is likely to produce only a little local pain and pruritus. If tuberculous infection is present, the local reaction is more marked, with vesiculation, ulceration, and even granuloma annulare or necrosis. 

Thimerosal has also been associated with false positive reactions to old tuberculin, ototoxicity, and an unusual reaction to aluminum in which a patient suffered a burn 5 cm in diameter at the site of an aluminum foil diathermy electrode after preoperative preparation of the skin with a 0.1% w/v thimerosal solution in ethanol (50%). Investigation showed that considerable heat was generated when such a solution came into contact with aluminum. 

A 35-year-old male has recently converted to positive on a purified protein derivative of tuberculin (PPD) test for TB. INH is given as prophylaxis. 

Freund, J. The sensitiveness of tuberculous guinea pigs one month old to the toxicity of tuberculin. J. Immunology 17, 465—471 (1929). 

A 43-year-old female on corticosteroids for Takayasu arteritis, INH for suspicious positive tuberculin skin test for past three months and escistalopram 20 mg/day for past month, developed acute onset of fever and confusion. Neurological examination revealed fever, rigidity, clonus, bilateral positive Babinsky and Hoffman signs... 

A 56-year-old patient with rheumatoid arthritis, who was started on INH chemoprophylaxis for a positive tuberculin skin test, developed interstitial pneumonia 2 weeks after the start of INH. The result of Drug Lymphocyte Stimulation Test (DLST) for INH was positive with the peripheral blood lymphocytes (stimulation index 208%). Trans-Bronchial Lung Biopsy specimens showed cellular no specific interstitial pneumonia pattern... 

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