Cutaneous tuberculosis in Adult
Alerts and Notices
Synopsis
Cutaneous tuberculosis (CTB) is caused by M tuberculosis, Mycobacterium bovis, and the Bacillus Calmette–Guérin (BCG) vaccine. It is exceedingly rare, only occurring in 1%-2% of extrapulmonary TB cases. CTB is more common in children, pregnant individuals, and HIV-infected persons. Cutaneous manifestations of TB can be subclassified into 4 categories.
Exogenous Sources: Primary inoculation TB occurs at sites of trauma, abrasions, or wounds or at mucous membranes.
- In patients with no immunity against TB, a scab or chancre forms at the wound site and can be associated with regional lymphadenopathy after several weeks. Lymph nodes can eventually suppurate, abscesses can form, and fever and pain can develop.
- In previously sensitized individuals, primary inoculation can lead to tuberculosis verrucosa cutis (warty tuberculosis) and is not usually associated with systemic symptoms.
- Scrofuloderma results from involvement of skin overlying a contiguous TB focus, usually a lymph node, bone, joint, or lacrimal gland. It is the most common form of CTB in children.
- Orificial TB is a rare mucosal autoinoculation TB from pulmonary, genitourinary, or intestinal disease shedding organisms that seed the adjacent orifices.
- Lupus vulgaris results from hematogenous spread and is a progressive form of CTB seen in individuals with prior sensitivity and low immunity.
- Tuberculous gumma (metastatic tuberculous abscess) is a rare form of hematogenous TB.
- Acute miliary TB is a rare but life-threatening form of hematogenous TB seen in patients with low immunity.
- Micropapular (lichen scrofulosorum)
- Papular (papulonecrotic tuberculid)
- Nodular (erythema induratum). Erythema nodosum can be also seen in pulmonary TB. Lesions are typically asymptomatic but may be painful. Localized adenopathy may occur.
All forms of CTB including tuberculids require systemic treatment. Without treatment, lesions can persist for months to years. The prognosis of miliary TB is often poor.
Codes
ICD10CM:A18.4 – Tuberculosis of skin and subcutaneous tissue
SNOMEDCT:
66986005 – Cutaneous tuberculosis
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
Nontuberculous mycobacterial infection (ie, Mycobacterium marinum, Mycobacterium avium complex [MAC]) can be clinically indistinguishable from CTB.Primary inoculation TB
- Deep fungal infection
- Nocardiosis
- Pseudomonal folliculitis
- Primary syphilis
- Leishmaniasis (Old World and New World)
- Yaws
- Tularemia
- Bartonellosis
- Cat-scratch disease
- Impetigo
- Ecthyma
- Cellulitis
- Blastomycosis
- Chromoblastomycosis
- Tertiary syphilis
- Verrucous epidermal nevus
- Hypertrophic lichen planus
- Halogenoderma
- Verruca vulgaris
- Prurigo nodularis
- Sporotrichosis
- Actinomycosis
- Coccidioidomycosis
- Mycetoma
- Lymphogranuloma venereum
- Acne conglobata
- Hidradenitis suppurativa
- Aphthous ulcers
- Syphilis (all stages) (see secondary syphilis)
- Lymphogranuloma venereum
- Blastomycosis
- Rhinoscleroma
- Oral malignancy
- Deep fungal infection
- Leishmaniasis (Old World and New World)
- Tertiary syphilis
- Discoid lupus erythematosus
- Lymphocytoma cutis
- Tuberculoid leprosy
- Pyodermatitis vegetans
- Sarcoidosis
- Rosacea
- Squamous cell cancer
- Pityriasis lichenoides et varioliformis acuta (PLEVA)
- Secondary syphilis
- Lymphomatoid papulosis
- Varicella
- Perforating disorders
- Vasculitis
- Prurigo nodularis
- Lichen nitidus
- Lichen planus
- Papular eczema
- Papular sarcoidosis
- Lichenoid secondary syphilis
- Erythema nodosum and other panniculitides
- Polyarteritis nodosa and other medium vessel vasculitides
- Tertiary syphilis
- Nodular vasculitis – an eruption with a similar clinical and histopathologic appearance but not associated with TB
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Therapy
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References
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Last Reviewed:08/20/2017
Last Updated:08/10/2021
Last Updated:08/10/2021
Cutaneous tuberculosis in Adult