A stye is a small bump on the eyelid that is red, swollen and painful. It is caused by inflammation of specialized oil glands in the eyelid. A stye is usually caused by a minor infection from bacteria that live on your skin. People with a skin condition called acne rosacea are more likely to get styes and may get them repeatedly.
Symptoms• Tender, red, swollen bump on the upper or lower eyelid.
• May form a head like a pimple and drain pus.
An ophthalmologist (eye doctor) can diagnose a stye using a biological microscope.