Cutaneous tuberculosis, different clinical spectrum of the same disease: the importance of pre-test probability

This report presents three cases of cutaneous tuberculosis that were identified at the Calderon Hospital in Quito, Ecuador. The first case involved a 44-year-old man who had tuberculosis verrucosa cutis, characterized by circinate erythematous areas, ulcerated nodules, and verruciform plaques extending from the right lower limb to the hip. In the second case a 50-year-old woman with a 1-year history of pruritic dermatosis in the left ciliary area was diagnosed with lupus vulgaris. In the third case, a 23-year-old man with erythematous nodules draining caseous material at the neck, thorax, and axillary region was diagnosed with scrofuloderma. It was discovered that nearly every laboratory test that was accessible had drawbacks as a diagnostic technique. Correlating clinical and epidemiological features with the pretest probability is crucial for optimizing indicators and confirming or ruling out the diagnosis in immunocompromised and high-risk individuals with atypical lesions.