Fungi are microorganisms characterised by cell walls made from a substance called chitin. Most fungi are harmless to humans and some are edible. Other fungi can be infectious and may lead to life-threatening diseases. Fungi reproduce by releasing spores that can be picked up by direct contact or even inhaled. Fungal infections often affect the lungs, skin or nails. Some infections may also penetrate the body to affect organs and cause whole-body infections. 

Examples of fungal infections include: 

• Athlete’s foot: itching, scaling or cracking of the skin 
• Ringworm: reddish, itchy, scaly rash usually on the skin and scalp 
• Thrush: caused by the fungus Candida albicans which can infect the mouth, vagina, stomach and urinary tract.

Fungi that commonly cause skin diseases are called dermatophytes. “Dermatophytes” doesn't refer to a particular group of fungi, but rather to the fact that they attack the dermis, or skin. Fungal infections of the skin can be treated with topical creams as well as prescription drugs.