Most candidial infections result in minimal complications such as redness, itching and discomfort, though complications may be severe or even fatal if left untreated in certain populations. In immunocompetent persons, candidiasis is usually a very localized infection of the skin or mucosal membranes, including the oral cavity (thrush), the pharynx or esophagus, the gastrointestinal tract, the urinary bladder, the fingernails or toenails (onychomycosis), and the genitalia (vagina, penis).
Candidiasis is a very common cause of vaginal irritation, or vaginitis, and can also occur on the male genitals. In immunocompromised patients, Candida infections can affect the esophagus with the potential of becoming systemic, causing a much more serious condition, a fungemia called candidemia.
Thrush is commonly seen in infants. It is not considered abnormal in infants unless it lasts longer than a few weeks.
Infection of the vagina or vulva may cause severe itching, burning, soreness, irritation, and a whitish or whitish-gray cottage cheese-like discharge, often with a curd-like appearance. These symptoms are also present in the more common bacterial vaginosis. In a 2002 study published in the Journal of Obstetrics and Gynecology, only 33% of women who were self-treating for a yeast infection actually had a such an infection, while most had either bacterial vaginosis or a mixed-type infection. Symptoms of infection of the male genitalia (balanitis thrush) include red skin around the head of the penis, swelling, irritation, itchiness and soreness of the head of the penis, thick, lumpy discharge under the foreskin, unpleasant odour, difficulty retracting the foreskin (phimosis), and pain when passing urine or during sex.
Perianal candidiasis can cause pruritis ani. The lesion can be erythematous, papular or ulcerative in appearance, and it is not considered to be a sexually transmissible disease.
Esophageal candidiasis can cause dysphagia (difficulty swallowing), or less commonly odynophagia (painful swallowing)