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History:  46 year old female with an extensive plaque-like lesion over the face.  A self-resolving papule then plaque had occurred 40 years earlier at the age of 6, then has waxed and waned in the same location.  No history of trauma or bites.  She has received sporadic medical attention and on one occassion a brief cource of therapy resulted in some improvement.

Epidemiology:  Born in rural highlands of Piura in the north and now lives in Trujillo on the dry coast of Perú.  No specific TB exposures.  No IV drugs or HIV risk factors.  No history of swimming in contaminated water.

Physical Examination:  Afebrile.  Abnormalities restricted to face [Images A, B].  CNS exam normal.

Laboratory Results:  Hct. 40.  WBC normal with normal differential.  CXR normal.  Culture of skin biopsy for bacteria, fungi, AFB all negative.

Discussion:  PPD reaction 18 X 12 mm.  Skin biopsy showed a tuberculoid like granulomatous (non-caseating) reaction with some giant cells throughout the dermis but without epithelial hyperplasia [Images C, D].  The patient was placed on 4-drug anti-TB therapy and within 4 weeks the lesions were healing with good granulation tissue [Image E] and Image F shows the scar 1 year after initiation of therapy.  Further history was obtained that the first episode many years ago had response to a short course of streptomycin.

Cutaneous tuberculosis can be divided into multibacillary and paucibacially forms.  The multibacillary forms include primary-inoculation TB or tuberculous chancre (by direct inoculation), scrofuloderma (scrofula) by extension from underlying tissue, TB periorificialis (by extension), and acute military TB and gumma (by hematogenous dissemination).  These forms of the disease show abundant mycobacteria in the skin that can readily be seen by direct visualization of Ziehl- Nielson stained material and can be easily isolated by culture of biopsy material.  In contrast, the paucibacillary forms are those where there are sparse bacilli seen on histology and the microorganisms are difficult to isolate.  Paucibacillary disease includes those forms of cutaneous TB that occur either by direct inoculation, or through re-exposure in a previously sensitized individual, such as tuberculosis verrucosa cutis.  In paucibacillary cases presenting as lupus vulgaris on the face, hematogenous dissemination is implicated from an other unrecognizable site.  Lupus valgaris affecting an extremity is likely a result of local re-inoculation in an otherwise sensitized individual.  Lupus vulgaris is the most common form of cutaneous TB in India, Pakistan, and Tunisia, and used to be the predominant form seen in Europe.  Females seem to be more commonly affected.

In lupus vulgaris, the macroscopic appearance is the most characteristic: a slowly enlarging plaque with a slightly elevated verrucous border and central atrophy.  The consistency is soft, and the color is reddish brown, having a classic apple jelly appearance on diascopy.  Lupus vulgaris of the face produces scarring and facial deformity.  Lesions may ulcerate at the center and cause exophytic growth, especially on the nose.  Lesions affecting the earlobe may have a pseudotumoral appearance.  The histology will characteristically show multiple noncaseating granulomas with sparse or absent acid-fast bacilli.  Mycobacterial culture is frequently negative though recent studies have shown MTb DNA by PCR in over half of cases investigated.  PPD testing is positive and the lesions should respond rapidly to conventional therapy.  Thus, diagnosis of lupus vulgaris is made by a combination of clinical presentation, markedly positive TB skin test, response to anti-TB therapy, and characteristic histologic findings (see above).

The prognosis in lupus vulgaris is good due to the light bacillary load (unless there are resistant organisms).  A clinical response should be seen by 4-6 weeks of a standard 6-month TB course, which is faster than in multibacillary disease such as scrofuloderma.  Recurrence is rare.