If the staphylococcal bacteria present in the mouth reach the eyelid and block the glands present there, the result will be a painful nodular and inflamed extrusion called a sty. The eyelid is going to swell up, and the result is going to show in a yellow or white pimple-like spot. A doctor will need to treat these sties by either opening them up or by asking you to apply a local ointment. Sties can be caused by a variety of reasons, but they are not contagious.
An external or an internal sty (in the inner portion of the eyelid) might result from using an infected eye makeup wand regularly. It is generally seen when a person goes to sleep without washing the face and removing eye makeup. In the same manner, if you use outdated cosmetics, there is a chance that you are going to suffer from sties.
If your skin is extremely oily, and you also happen to have an oily scalp, there is a chance that you are going to suffer from occasional and recurring sties. This oil blocks up the glands from discharging normally, and the eyelid swells up.
Not washing your face is one way of getting sties. Dirty hands are a definite way of carrying germs to the eyes.
There are a number of inflammatory diseases that infect the eyelid and cause sties. Out of these diseases, rosacea, meibomitis and blepharitis are the most common.
Hormonal changes during adolescence or during any other phase of life can cause sties to appear on eyelids.
Stress can also be a factor in the formation of sties in the eye. In times of stress, people have a tendency to rub their forehead and other parts of the face, including the eyes.
Lowered Immune System
An immune system that is not in good shape is more susceptible to infections.