Inflammation of the eyelids.

A cyst on the eyelid due to plugging of the meibomian glands, fat-secreting glands of the eyes.

A plugged hair follicle. May be open (blackhead) or nearly closed (whitehead).

An experiment or clinical trial that includes an untested comparison group, referred to as a "control group."

Pertaining to the skin.

A research procedure in which neither the patient nor the investigator knows who is receiving the experimental substance or procedure and who is receiving a placebo. Done to avoid bias in the study.

Swelling from abnormally large amounts of fluids in the tissues.

Abnormal redness of the skin.

Subtype 1 rosacea, characterized by flushing and persistent redness. Visible blood vessels may also appear.

Transient redness of the face and neck.