Chronic mucocutaneous candidiasis (CMC)

Chronic mucocutaneous candidiasis (CMC) is characterized by persistent Candida (fungus) infections of the mucous membranes, scalp, skin, and nails. Rarely, the infection may spread to the bloodstream or internal organs. CMC is usually hereditary and presents with persistent oral Candida infections (thrush) soon after birth. Later, the nails and skin become chronically infected. These infections respond to anti-Candida treatment but recur when the treatment stops.

CMC is associated with a selective T cell deficiency to Candida and a few related fungi. Except for this T cell deficiency, patients with CMC have a normally functioning immune system. Despite widespread Candida infection, the most common abnormal laboratory finding is a negative delayed hypersensitivity skin test to Candida antigen.

One hereditary form of CMC is APECED syndrome (autoimmune polyendocrinopathy-candidiasis-ectodermal dysplasia) associated with multiple endocrine problems (for example, hypothyroidism, diabetes, or Addison disease) due to an AIRE gene variant on chromosome 21. However, the CMC in this disease is also partly due to autoantibodies directed against critical Candida-fighting molecules made by the disordered immune system. Several other forms of CMC are due to variants in the gene signal transducer and activator of transcription 1 (STAT1). Other causes of CMC are associated with autoantibodies to critical Candida-fighting molecules and with very uncommon variants in genes such as interleukin 17. Treatment requires lifelong antifungal medicines.