What is your work-up for acquired keratoderma?

The differential diagnosis for acquired keratoderma is broad and includes categories such as inflammatory skin disorders (such as pityriasis rubra pilaris, cutaneous T cell lymphoma, etc), infections (syphilis, crusted scabies, HIV, etc), medications (tyrosine kinase inhibitors, etc), nutritional deficiency, paraneoplastic presentations, external insults (chemical exposure), and metabolic derangement (including hypothyroidism) among others. Rarely, genetic causes of keratoderma can also present in a delayed fashion. As such, a detailed history (including family history, medications, occupation, etc), review of systems, and physical examination are the most important initial steps in evaluating patients with acquired PPK with additional stud...