Table 2.
Cutaneous TB.
| Treatment: Systemic anti-TB therapy is the mainstay of cutaneous TB treatment. Treatment should be continued for at least 2 months after complete resolution of skin lesions. | ||||
|---|---|---|---|---|
| Disease | Description | At-risk population | Cutaneous manifestations | Complications and importance of treatment |
| Exogenous inoculation (inoculation of organism into the skin) | ||||
| Primary inoculation TB | ■ Occurs in nonsensitized individuals | ■ Primarily in children in endemic areas of TB | ■ Typically <1 cm red-brown papule or nodule on face and extremities, progressing to shallow undermined ulcer formation with granulomatous base | ■ Cutaneous lesions can persist up to 1 year if left untreated |
| ■ Rare form of cutaneous TB | ■ Most commonly affects sites of minor trauma where skin barrier is compromised | ■ Painless regional lymphadenopathy progressing to draining sinuses | ■ Leaves scar after resolution | |
| ■ Direct entry of organism into the skin or mucosa causing an infection | ■ Erythema nodosum, lupus vulgaris, scrofuloderma may copresent | ■ Patient becomes sensitized to TB | ||
| TB verrucose cutis | ■ Occurs in previously sensitized individuals | ■ Children exposed to contaminated areas | ■ Solitary 1–5 cm red-brown or violaceous indurated plaques with warty appearance | ■ Elephantiasis and lymphostasis may be seen |
| ■ More common form of cutaneous TB | ■ Exposure to contaminated environment may increase risk | ■ Potential fissure formation leading to purulent drainage | ■ Can persist for years if left untreated | |
| ■ Direct entry of organism into the skin or mucosa | ■ Occupational exposure to mycobacteria (e.g., pathologist, laboratory technicians, farmers) increases risk | ■ Acral extremities (fingers, dorsum of the hands), ankle, or buttocks most commonly affected | ||
| Contiguous spread (transmission to the skin from adjacent structures) | ||||
| Scrofuloderma (TB colliquative cutis) | Direct extension of infection from deep structure (e.g., lymph node, bone, joint, epididymis) into overlying skin | ■ Most common in children, adolescents, and older adults | ■ Firm subcutaneous red-brown nodules progressing to ulcer and sinus tract formation that drain clear, purulent, or caseous material | ■ Lesions take years to completely resolve if untreated. Leaves scar tissue |
| ■ Nodules overlying TB infection in the neck, axillae, and groin | ■ Lupus vulgaris may develop close to scrofuloderma lesions | |||
| ■ Cervical lymph nodes most commonly affected | ||||
| ■ Linear distribution of nodules overlying chain of lymph nodes underneath | ||||
| TB cutis orificialis | ■ Orifical TB is rare | ■ Most commonly among older adults | ■ Single red-yellow nodule rapidly progressing into painful, circular, friable, and irregularly shaped ulcer | ■ Significant internal organ involvement is common; thus, vigilant surveillance of underlying TB infection is needed |
| ■ Autoinoculation of mucocutaneous surfaces close to orifices near draining sites or sites of visceral infection | ■ May have punched-out appearance | ■ Does not resolve spontaneously; treatment necessary because could lead to fatal miliary TB | ||
| ■ Difficult to treat and can progress through treatment | ||||
| ■ Presence of TB cutis orificialis could indicate a poor overall prognosis | ||||
| Lupus vulgaris | ■ Chronic and progressive form of cutaneous TB | ■ 2–3 times higher prevalence in women | ■ Variable cutaneous presentation | ■ Lupus vulgaris could be rare complication of BCG vaccination |
| ■ Due to reactivation of TB in patients with moderate-to-high immunity against pathogen | ■ People in Europe, parts of India, and tropical regions are most commonly affected | ■ Red-brown papules coalescing into asymptomatic plaque with central clearing and atrophy, most commonly on the head and neck; lower extremities and buttocks involvement more common in the tropics | ■ Can develop after scrofuloderma | |
| ■ Spready by direct extension from underlying site of infection or by hematogenous spread | ■ Most common type of cutaneous TB in Europe and Hong Kong | ■ Plaques may have serpiginous or verrucous borders | ■ Does not resolve spontaneously; treatment necessary to prevent significant disfigurement from growing plaques, resulting in ulceration and destruction of underlying tissues (particularly in the nose, ears, and lips) | |
| ■ Other variable forms include hypertrophic, ulcerative, vegetative forms | ||||
| ■ Differential location by region: head and neck in the western world; on lower extremities and buttocks in tropical and subtropical regions | ||||
| Hematogenous spread (transmission via bloodstream) | ||||
| Metastatic TB abscesses (TB gummas) | Occurs due to hematogenous spread of organism from primary site of infection to subcutaneous tissue during state of compromised immunity | ■ Children malnourished or of low socioeconomic status | ■ Single or multiple nontender, fluctuant, subcutaneous nodules that progress to ulcers and draining sinuses typically in the extremities | ■ May spontaneously resolve without treatment |
| ■ Immunosuppressed adults (uncommon in immunocompetent individuals) | ■ May persist for several years without treatment in immunocompromised patients | |||
| ■ Negative prognostic factor when found in immunocompromised or malnourished people | ||||
| Acute miliary TB (TB cutis miliaris disseminata) | Rare form of cutaneous TB from hematogenous spread from primary infection focus, such as the lung | ■ Infants | ■ Cutaneous presentations uncommon; appear as tiny papules or vesiculopapules; rarely, macular, pustular, or purpuric lesions, indurated ulcerating plaques, and subcutaneous abscesses can occur | ■ Miliary TB is fatal if untreated |
| ■ Patients with impaired cell-mediated immunity (e.g., AIDS) | ■ Cutaneous lesions typically resolve in 4 weeks of treatment, leaving hypopigmented depressed scars | |||
| Lupus vulgaris | See contiguous spread | |||
| Hypersensitivity reaction (non-infectious etiology) | ||||
| Tuberculids | Tuberculids are cutaneous hypersensitivity eruptions to M. tuberculosis in patients with moderate or high levels of immunity against the pathogen. Bacilli are typically not detectable in tuberculid lesions. There are three types of tuberculids | |||
| Papulonecrotic tuberculid | ■ Chronic, recurrent, and symmetric eruption of necrotizing skin papules in crops | ■ Children and young adults | ■ Symmetric, asymptomatic crops of dusky red pea-sized papules with crusting and ulceration on extensor extremities; pustules may be present | ■ May spontaneously resolve after several weeks; responds dramatically to anti-TB therapy |
| ■ Most common form of tuberculid | ■ Lymphadenitis may be present | ■ Lesions spontaneously involute, leaving many pitted scars | ||
| ■ Presence of active lesion adjacent to scarring is diagnostic clue | ■ Without treatment, could persist for years | |||
| -Chronic recurrent condition | ||||
| Lichen scrofulosorum (TB cutis lichenoides) | ■ Tuberculid characterized by small papular lesions with or without active TB | ■ Children and young adults | ■ Numerous asymptomatic, 1–5mm perifollicular grayish-white lichenoid papules in groups on the trunk, papules on the trunk | ■ Resolves spontaneously after several months to years without scarring |
| ■ May be easily missed due to similar appearances as other dermatoses | ■ Most commonly associated chronic TB of lymph node and bones | ■ With anti-TB treatment, complete resolution within weeks to months | ||
| ■ Rarer | ||||
| Erythema induratum of Bazin | ■ Granulomatous lobular panniculitis of lower extremities | ■ Predilection for women (80%–90% of cases) with age peaks in early adolescence and around menopause | Bilateral, symmetric, erythrocyanotic nodules on posterior lower extremities, progressing slowly to ulceration and central necrosis with irregular deep lesions and undermined borders | ■ Spontaneously resolves over several months leaving atrophic hyperpigmented scars |
| ■ Common | ■ Several lesions at various stages are seen, leaving scars and hyperpigmentation | |||
| ■ Chronic condition with frequent recurrence | ||||
| ■ Anti-TB therapy, potassium iodide, nonsteroidal anti-inflammatory drugs, dapsone, colchicine, glucocorticoids have been useful | ||||
| Others | ||||
| BCG vaccination reactions | ■ BCG is only vaccine used against TB today containing live attenuated M. tuberculosis strain | - | ■ May develop red, tender, indurated papule at injection site with possible crusting and draining 2–6 weeks after injection | ■ Injection site reaction spontaneously heals in several weeks, leaving superficial scar |
| ■ Rarely given in United States, but still commonly used in low- and middle-income countries | ■ Other local tissue reactions, ulceration, abscess formation, scrofuloderma, lupus vulgaris, erythema induratum of Bazin, papulonecrotic tuberculid, lichen scrofulosorum-like lesions may occur | ■ More serious, but rare complications include anaphylactic reactions | ||
| ■ Dermatologic complications can occur | ||||
BCG, Bacille Calmette-Guerin; TB, tuberculosis.