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tuberculid

Classification: 3 main types of tuberculids - erythema induratum - lichen scrofulosorum - papulonecrotic tuberculid [3] Pathology: - type-4 hypersensitivity reaction to Mycobacterium tuberculosis Clinical manifestations: - erythema induratum: localized red-to-violaceous nodules or plaques on posterior calf - lichen scrofulosorum: many discrete, often monomorphic, 2-4-mm, flat-topped papules, generally on trunk - papulonecrotic tuberculid: symmetric, recurring eruption of 2-8-mm, firm, inflammatory papules -> pustules becoming necrotic over time, scarring over a period of weeks - if untreated, may persist for years [3] Laboratory: - skin biopsy - acid fast stain generally unrewarding (hypersensitivity) - mycobacterial cultures also generally unrewarding [3]

General

type 4 hypersensitivity; T-cell-mediated (delayed) hypersensitivity cutaneous tuberculosis; includes tuberculous chancre, tuberculosis verrucosa cutis

References

  1. Jordaan HF, Schneider JW, Abdulla EA. Nodular tuberculid: a report of four patients. Pediatr Dermatol. 2000 May-Jun;17(3):183-8. PMID: 10886748
  2. Jordaan HF, Schneider JW, Schaaf HS et al Papulonecrotic tuberculid in children. A report of eight patients. Am J Dermatopathol. 1996 Apr;18(2):172-85. PMID: 8739993
  3. Rothaus C A Man with Rash, Abdominal Pain, and Lymphadenopathy. NEJM Resident 360. Jan 16, 2019 https://resident360.nejm.org/content_items/a-man-with-rash-abdominal-pain-and-lymphadenopathy