Erythroderma is the generalized erythema and scaling of skin affecting at least 90% of body surface area. Understanding and correcting the underlying cause and precipitating factors are important in the management of erythroderma. Here, we report a case of treatment-resistant psoriatic erythroderma, which responded to anti-tubercular therapy (ATT). A 55-year-old male who is a known case of psoriasis presented with generalized erythema and scaling all over the body for 2 months, preceded by intake of herbal medications. On examination, erythroderma involving the trunk, upper and lower extremities, scalp, face, palms, and soles was present. Diagnosis of psoriatic erythroderma precipitated by herbal medications was made. The patient was started on cyclosporine and thereafter, acitretin was added, but there was a suboptimal response. We observed better response when prophylactic antibiotics were added, which gave a clue on a hidden infection triggering the erythroderma, that is yet to be addressed. On further evaluation, Mantoux test was positive and high-resolution computed tomography chest revealed lesions suggestive of pulmonary tuberculosis (TB). The patient was started on standard ATT and a Near-complete resolution of the erythroderma was observed in 2 weeks. To the best of our knowledge, there are not many reports of erythroderma in preexisting dermatosis triggered by TB in the literature. We put forward this case report as an attempt to stress the fact that a meticulous search for the precipitating factors is important in the management of erythroderma.