There are several types of cysts, but the most common are milium cysts. In many cases, these cysts occur in groups. Milia is a medical term for multiple cysts.
Keratin becomes trapped beneath the skin’s surface, causing milia to develop. In skin, hair, and nail cells, keratin is a strong protein.
A person of any ethnicity or age can develop milia. However, new-borns are the most susceptible.