A-Z OF SKIN

The spectrum of clinical manifestations is wide and depends upon:

• History of previous exposure to the bacteria that causes tuberculosis or bacille Calmette-Guerin (BCG) vaccination.
• The immune status of the patient – general health, presence or absence of other infections and whether has developed immunity.
• Whether the infection has developed by direct inoculation or has spread from internal organs or by bloodstream.

Primary Inoculation Tuberculosis

Also known as tuberculous chancre, this occurs through direct exposure with the mycobacterium via an injury that caused a break in the skin. This may include accidental injury, tattooing, piercings, or injections.

It is a rare form of CTB occurring in individuals that have not had prior exposure to the mycobacterium.

In rare cases children, non-immune individuals amidst high TB prevalence regions or poor living conditions can be affected.

• Appears as a painless brown-red papule or nodule 2-4 weeks after initial injury. This can then develop into a painless ulcer. Most cases do not resolve without treatment.
• Enlarged lymph nodes may be present, especially in children
• May affect face, eyes, mouth, hands and legs

Tuberculosis Verrucosa Vutis

Presents as a slow growing, painless, warty plaque at the site of inoculation and occurs in individuals that have had previous exposure to the mycobacterium. This form of infection through direct exposure is more common than primary inoculation tuberculosis. Commonly affected sites include the lower legs and buttocks.

Lupus Vulgaris

Presents as a chronic, slow growing, painless brown-red plaque. Lupus vulgaris (LV) is one of the more common presentations of CTB and occurs as a result of mycobacterium spread from the bloodstream or internal organs in patients with moderate to high immunity. If the individual has developed a fairly high level of immunity to the presence of the bacteria, then the skin lesions seen are often localised and well-defined.

Scrofuloderma

Presents as painless, ulcerated plaques with fistula or sinus formation and discharge. It is common in endemic areas and occurs over affected lymph nodes, bones or joints. Lesions may spontaneously heal with scarring.

Orificial Tuberculosis

Occurs in advanced disease with organ involvement and patients with weakened immune systems, where they may develop painful or painless papules, nodules or ulcers in the mouth, nasal passage, and anogenital skin or mucosa.

Miliary Tuberculosis

For individuals with little immune resistance to the infection, malnourished, have infections such as HIV or on immune suppressive medications, the mycobacterium may spread via the blood stream. Individuals may develop red papules and pustules. It is associated with poorer outcomes.

Metastatic Tuberculous Abscess

Also occurring in individuals with weakened immune systems, this presents as fluctuant, subcutaneous nodules that may penetrate the skin and form draining sinuses and ulcers. These are usually found on the arms and legs and are due to the spread of the mycobacterium via the bloodstream.

Tuberculid

Tuberculid is probably best considered as an allergic reaction to parts of mycobacterium tuberculosis in individuals with a high level of immunity to the bacteria.