Common variable immunodeficiency (CVID) is the most prevalent of the primary immunodeficiencies, and is characterised by low IgG and IgA, and sometimes IgM. There is some evidence of genetic susceptibility, with 20% of patients having a dominantly inherited disorder with variable expression. It is a heterogeneous disorder with protean manifestations, and as a result diagnosis is often delayed until the second or third decade, with resultant irreversible organ damage, in particular bronchiectasis. Effective treatment is available with regular 3-4-weekly infusions of immunoglobulin. The mechanism of the immunodeficiency has not yet been fully elucidated. The majority of patients present with recurrent sinopulmonary infection, however, this is a multisystem disorder and thus presents to physicians in diverse specialties including dermatology. Other clinical features of the disorder include gastrointestinal problems, granulomatous inflammation, cutaneous features, unusual presentations of enteroviral and mycoplasma infection, an increased incidence of autoimmunity, and a predisposition to lymphoma and stomach cancer. Therefore a knowledge of the disorder and appropriate suspicion by all clinicians of the possibility of such rare problems and a consequent low threshold for performing relevant investigations is imperative in allowing early recognition and instituting effective treatment. We describe a case of CVID identified when the patient developed widespread skin infection, fever and malaise. This case is an important example of a possible presentation of CVID within the dermatology clinic and demonstrates that maintaining a high level of clinical suspicion is essential for the diagnosis of the rare primary immunodeficiencies.