Infection with the yeast candida is a quite common disease. Its occurrence might be harmless, however, Candida infections often present with an underlying systemic disease. Thus, candidiasis in some cases can be considered as an indicator for e.g. diabetes mellitus or immune deficiency (i.e. HIV or leukaemia). Of note, we have to distinguish the colonisation and the infection with Candida because only the presence of the yeast together with clinical symptoms is an indication for treatment. The latter has to be adapted according to age, localisation and potentially underlying systemic disease. A special form of Candidiasis constitutes the chronic mucocutaneous candidiasis which can occur in line with hereditary immune deficiencies or also isolated. In the present review we discuss the current status of diagnostic and therapy of mucocutaneous candidiasis as well as the (patho-) immunologic background of yeast infections using the example of a special case of chronic mucocutaneous candidiasis.