Fungal diseases can affect anyone. Learning about them can help you and your doctor recognize the symptoms of a fungal disease early and may help prevent serious complications.Fungal diseases are often caused by fungi that are common in the environment. Most fungi are not dangerous, but some types can be harmful to health.Mild fungal skin diseases can look like a rash and are very common. Fungal diseases in the lungs are often similar to other illnesses such as the flu or tuberculosis. Some fungal diseases like fungal meningitis and bloodstream infections are less common than skin and lung infections but can be deadly Fungi are everywhere. There are millions of different species of fungi on Earth, but only about 300 of those are known to make people sick. Fungal infections are often caused by microscopic fungi that are common in the environment. Fungi live outdoors in soil and on plants as well as on many indoor surfaces and on human skin