We present a case of Sneddon-Wilkinson disease in a 52-year-old female at her first presentation to dermatology. Outlined in the case are various investigations undertaken at this initial presentation, including rheumatologic and hematologic malignancy markers, which identified immunoglobulin A gammopathy. The systemic and topical therapies used to treat the patient's condition are described, as well as her response to these treatments. In this discussion, we explain the epidemiology, pathophysiology, and clinical presentation of Sneddon-Wilkinson disease. Various medical conditions having known association with Sneddon-Wilkinson disease are discussed, including immunoglobulin A or immunoglobulin G monoclonal gammopathies and lymphoproliferative disorders. A comprehensive differential diagnosis for Sneddon-Wilkinson disease is provided, including immunoglobulin A pemphigus, acute generalized exanthematous pustulosis and pustular psoriasis, among others. We describe the systemic and topical therapy options for the treatment of Sneddon-Wilkinson disease, of which first line treatment is systemic dapsone. This patient serves as an excellent case of Sneddon-Wilkinson disease with unexpected immunoglobulin A gammopathy.