Cutaneous TB can be acquired through direct infection of the skin (exogenous TB) or fromhaematogenous spread of TB elsewhere in the body.11 It may not always be obvious how the patient acquired the cutaneous TB.Haematogenous spread of TB may be the most likely cause in the first patient, as he hadrecently been treated for pulmonary TB and presented with low CD4+ count, putting him atincreased risk for disseminated infection. The gene discussed is CD4; the disease is pulmonary tuberculosis.