Papulonecrotic tuberculid in a 9-year-old American girl: case report and review of the literature

Immune-mediated tuberculous uveitis - A rare association with papulonecrotic tuberculid

The tuberculids are a group of distinct clinicopathological form of skin lesions representing hypersensitivity reaction to hematogenous dissemination of Mycobacterium tuberculosis or its antigen from an underlying active or a silent focus of tuberculosis elsewhere in the body in an individual with a strong antituberculous cell-mediated immunity and by definition do not show bacilli on special stains and are culture-negative. Ocular involvement can occur in tuberculosis, both due to direct invasion by the bacilli as well as an immune-mediated reaction; however, immune-mediated tuberculous uveitis occurring as a hypersensitivity response in association with PNT has hardly been reported in the literature. Here we report one such rare case.

Diagnosis of cutaneous tuberculosis by polymerase chain reaction using a species-specific gene

BACKGROUND

Diagnosis of tuberculosis (TB), especially cutaneous TBC, by conventional microbiologic methods is still a very laborious process and the results are usually inconclusive. Our purpose was to identify M. tuberculosis bacilli in uncultured clinical samples from skin lesions by means of the rapid, specific, and sensitive polymerase chain reaction (PCR).

METHODS

The PCR, using a set of species-specific primers, was performed on biopsies and fluid secretions from lesions.

RESULTS

A positive amplification reaction was observed in three of the four samples studied. For one of the samples, the result was confirmed by a positive culture in Löwenstein-Jensen medium and for the other two, by molecular hybridization and the clinical course of the patients after treatment. Samples obtained from a patient with panniculitis of Christian-Weber and a normal skin biopsy were included as negative controls.

CONCLUSIONS

We propose the PCR method as a tool for the diagnosis of cutaneous TBC. The presence of the M. tuberculosis in an erythema induratum of Bazin suggests a revision of the concept of this disease as a tuberculide reaction.

Papulonecrotic tuberculid secondary to disseminated Mycobacterium avium complex

BACKGROUND

Papulonecrotic tuberculid is a rarely reported cutaneous reaction to the mycobacterium bacillus. It is most often encountered in association with tuberculosis. The clinical and histologic picture of the entity is a distinctive one, but the etiology of the disease process is uncertain. Therapy directed against the causative organism is dramatically successful.

METHODS

A 35-year-old white man with AIDS was referred to the Dermatology clinic for evaluation of a widespread skin eruption. The skin lesions were biopsied for histopathology and culture. From the cutaneous cultures Mycobacterium avium complex (MAC) organisms were grown.

RESULTS

We report the first case of papulonecrotic tuberculid manifestation in an AIDS patient with disseminated MAC. Unusual features seen in this case include the predominance of pruritic eschars rather than asymptomatic papules and the confirmation by special stains of mycobacterium organisms within the skin biopsy. Papulonecrotic tuberculid has not been previously associated with either MAC or AIDS.

CONCLUSIONS

Papulonecrotic tuberculid should be a diagnostic consideration in immunocompromised patients with MAC whose clinical and histologic features are compatible with this rare entity.