Candidiasis is an opportunistic infection caused by Candida, a type of fungi. Fungi are eukaryotic organisms found in the form of yeasts, molds, or dimorphic fungi. is a form of yeast. Candidiasis occurs most commonly as a secondary infection in immunocompromised individuals. Synonyms of candidiasis include candidosis, moniliasis, and thrush. These are common inhabitants in the oral cavity, gastrointestinal tract, vagina penis, or other parts. They become pathogenic only when favorable conditions arise.  It can affect the oral cavity, vagina, penis, or other parts of the body. Candidiasis affecting the mouth is commonly called thrush. It presents as white patches on the tongue, throat, and other mouth areas. Soreness and difficulty in swallowing include other symptoms associated with thrush. The vagina, when affected with , is called a yeast infection.  Oral candidiasis can be pseudomembranous, erythematous, and chronic hyperplastic candidiasis. Pseudomembranous candidiasis is common in chronically ill patients and infants. It is presented as white, soft, slightly elevated plaques most commonly on the tongue and buccal mucosa. Plaques resemble curd and consist of tangled masses of fungal hyphae with intermingled desquamated epithelium, necrotic debris, keratin, leukocyte, fibrin, and bacteria. This white plaque, when wiped away, leaves an erythematous area. Erythematous candidiasis is also known as antibiotic sore mouth. It occurs as a sequel to the use of broad-spectrum antibiotics or corticosteroids. The lesions present as consistently painful erythematous areas along with central papillary atrophy of the tongue. It is also known as a kissing lesion when the palate is involved and exhibits erythema due to contact with the tongue.  Chronic hyperplastic candidiasis, also known as candidal leukoplakia, presents with firm white persistent plaques on lips, tongue, and buccal mucosa. These plaques may be homogenous or nodular and persist for years. It has premalignant potential. Candida associated lesions include denture stomatitis, angular cheilitis, and median rhomboid glossitis. Secondary oral candidiasis can also occur, which include chronic mucocutaneous candidiasis, chronic familial candidiasis, chronic localized mucocutaneous candidiasis, chronic diffuse mucocutaneous candidiasis, and candidiasis endocrinopathy syndrome. Vaginal candidiasis presents with genital itching, burning, and a white "cottage cheese-like" discharge from the vagina. The penis is less commonly affected by a yeast infection and may present with an itchy rash. Yeast infections may spread to other parts of the body resulting in fevers along with other symptoms and become invasive rarely.  Oral candidiasis is one of the most common fungal infections, affecting the oral mucosa. The yeast cause these lesions.  are among the components of normal oral microflora, and around 30% to 50% of people carry this organism. The rate of carriage increases with the age of the patient.  are recovered from 60% of dentate patients' mouths over the age of 60 years. There are many forms of species, which present in the oral cavity. Species of oral Candida include , , , , , , and . Oral candidiasis may present as a variety of disease entities in both normal hosts and the immunocompromised. These include hyperplastic or atrophic (denture) candidiasis, pseudomembranous candidiasis (thrush), linear gingival erythema, median rhomboid glossitis, and angular cheilitis. It can result in a broad range of clinical manifestations ranging from mild acute superficial infections to fatal disseminated disease. Disseminated candidiasis is almost exclusively in acquired or inherited immuno-deficiencies. Superficial candidiasis is the most common form.