Subacute cutaneous lupus erythematosus (SCLE) is an entity characterized by widespread polycyclic lesions that heal without scarring. Skin lesions with marked ultraviolet sensitivity are distributed in an annular and/or psoriasiform configuration. Idiopathic thrombocytopenic purpura, which is an autoimmune disease (ITP), is mediated by a destructive immunoglobulin G antibody response to the platelets' membrane components. We report a case of subacute cutaneous lupus erythematosus initially manifested as thrombocytopenia, which was diagnosed as idiopathic thrombocytopenic purpura (ITP) and treated with splenectomy. Seven months later, development of cutaneous involvement followed the diagnosis of ITP. The clinical and histological features of the lesions were compatible with SCLE. Serological evaluations showed a negative anti-nuclear antibody test and an elevated anti-SSB/La antibody level. Symptoms for systemic involvement were negative. Although the clinical features such as photosensitivity, discoid rash, and thrombocytopenia were in favor of SLE, the patient did not fulfill the criteria of the American Rheumatism Association (ARA) for SLE.