Cutaneous tuberculosis: epidemiological, clinical, diagnostic and therapeutic update

Tuberculosis is certainly one of the diseases considered to be ancient on planet Earth. The etiological agent of tuberculosis is Mycobacterium tuberculosis. This terrible bacterial infection still results in severe socioeconomic consequences to date, and its complete eradication represents a great challenge. It constitutes one of the most important public health problems in developing countries. According to the World Health Organization, this infection results in more than 4,000 deaths daily worldwide, with 10.4 million being affected annually and 1.5 million deaths from TB every year. With the emergence of the HIV/AIDS pandemic, the disease became the main cause of morbidity and mortality in patients infected with the human immunodeficiency virus. Cutaneous tuberculosis is a rare infection that represents 1% to 1.5% of extrapulmonary tuberculosis, whose etiological agents are Mycobacterium tuberculosis, Mycobacterium bovis, and the attenuated form of the bacillus Calmette-Guérin (BCG vaccine). Cutaneous tuberculosis can be exogenous; endogenous: caused by contiguity or autoinoculation and by hematogenous spread; induced by the Calmette-Guérin bacillus and manifest as a tuberculid. The diagnosis of the infection is carried out through the direct test, culture, histopathology, tuberculin skin test, polymerase chain reaction, interferon-gamma release assay, and genotyping. Drugs used comprise isoniazid, rifampicin, pyrazinamide and ethambutol.