A fungal infection, also known as mycosis, is a disease caused by fungi that invade tissues, causing superficial, subcutaneous, or systemic disease. These infections can affect various parts of the body, including the skin, nails, hair, lungs, and bloodstream. Common types include dermatophytosis (ringworm), candidiasis (yeast infection), and aspergillosis. Risk factors include weakened immune systems, antibiotic use, and warm, moist environments. Diagnosis often involves microscopic examination, culture, or molecular tests.