What is yeast infection? what is the cause of yeast infection?

Fungal: Yeast is a fungus, and a yeast infection is usually due to Candida species. It is treated with antifungal agents.

A fungal infection: Several factors can cause yeast infections- 1. Local balance of normal bacteria and fungi (flora) is disrupted, typically due to antibiotics; 2. Impaired immunity- this may be due to steroid use or having other illnesses such as hiv; 3. Misdiagnosis of symptoms in the absence of yeast from testing- adverse drug effects can be mistaken as a yeast infection.