The differential diagnosis for hypopigmented patches on the skin includes tinea corporis, tinea versicolor, progressive macular hypomelanosis, vitiligo, pityriasis alba, lichen sclerosus et atrophicus, morphea, sarcoidosis, leprosy, and syphilis. It is important first to rule out common causes of hypopigmentation with fine scaling, such as tinea corporis and tinea versicolor, using potassium hydroxide preparation. Evaluation of cutaneous sensation is necessary to rule out leprosy. Empirical topical steroids may improve skin lesions and pruritus but will alter the histologic pattern on future skin biopsies and further delay a correct diagnosis. Often, several skin biopsies are needed to confirm the diagnosis of mycosis fungoides. Diagnostic imaging is not indicated in patients without tumors, lymphadenopathy, or other evidence of systemic involvement.