Fungal infections may be caused by respiratory tract infections, gastrointestinal tract infections, skin infections and other reasons. 1. Respiratory tract infection: low immunity, poor resistance or malnutrition can easily cause oral fungal infections, which can spread through the mucous membrane of the throat causing respiratory tract fungal infections. 2. Digestive tract infection: due to the long-term use of glucocorticosteroids, it will cause damage to the body’s immunity, resulting in dysfunction of the digestive tract flora, fungi enter the body to reproduce in large quantities and invade the tissues, thus causing digestive tract fungal infections. 3. Skin infection: through direct or indirect contact with patients with fungal skin infections, or public slippers, can also cause cross-infection, causing fungal infections of the skin. Clinically, there are many factors leading to fungal infections, which should be treated under the guidance of professional doctors to clarify the cause of the disease and choose targeted treatment.