Acquired Ichthyosis in the Setting of Active Pulmonary Tuberculosis

Acquired ichthyosis is an uncommon disorder of cornification. It characteristically presents as symmetric scaling of the skin on the trunk and extensor surfaces of the extremities. It is clinically and histologically similar to ichthyosis vulgaris; however, acquired ichthyosis develops later in life and has been associated with various malignancies, infections, medications, autoimmune diseases, metabolic disorders, and malnutrition. We describe a case of a 35-year-old woman with active pulmonary tuberculosis and a history of breast cancer who presented with a several-month history of a widespread, scaly, pruritic skin eruption. Physical examination revealed fine, scaly patches on the extremities with relative sparing of the flexures and larger, scaly, ichthyosiform patches on the chest and back. Skin biopsy revealed orthokeratotic hyperkeratosis and a diminished granular layer, consistent with a diagnosis of acquired ichthyosis. Further evaluation, including positron-emission tomography/computed tomography scan, revealed hypermetabolic infiltrates and cavitation in the lungs, consistent with active pulmonary tuberculosis; there was no evidence of new or recurrent malignancy. The patient was treated with antituberculosis drugs and topical ammonium lactate cream. With incident cases rarely reported in the literature, this case of new-onset ichthyosis in the setting of active pulmonary tuberculosis highlights the distinctive clinical and histologic features of acquired ichthyosis and emphasizes the relationship of acquired ichthyosis with underlying systemic disease, particularly infection.