What is the difference between comedones and milia?

How can you tell them apart?

A closed comedone has no readily visible central pore, so the absence of an obvious opening does not automatically mean a bump is milia. Whiteheads can look very similar to milia. A clinician can usually identify milia by examining the bumps; a biopsy, which means examining a small skin sample, is occasionally needed.236

One cyst is called a milium and several are called milia, because even a tiny bump has paperwork.3

Why do comedones and milia form?

A whitehead forms when excess oil and dead skin cells plug a pore's opening. A blackhead forms when the opening widens and the contents remain exposed to air. The dark colour comes from a reaction with oxygen, not dirt, so scrubbing harder is cleaning up the wrong suspect. Scrubbing can worsen acne.57

Milia form when dead skin cells become trapped beneath the surface and harden into small cysts. Primary milia occur in children and adults without a preceding injury. Secondary milia develop as skin heals after damage such as burns or blistering. Some milia can also follow heavy creams or ointments, or prolonged use of steroid creams. Do not use prescribed steroids for longer than your clinician directs.23

What should you do for comedones?

Treat blackheads and whiteheads with acne treatment rather than picking. Topical retinoids are medicines applied to the skin that help unclog pores. Adapalene is available without a prescription in some markets. A benzoyl peroxide wash can also help reduce acne bacteria.7

Give acne treatment six to eight weeks to work. If comedones remain, a dermatologist can consider prescription treatment or professional comedone extraction. Picking whiteheads can cause more whiteheads and acne scars; squeezing blackheads can cause infection or permanent scarring.57

What should you do for milia?

Milia are harmless and do not need treatment unless their appearance bothers you. Adult milia can clear within weeks, but some persist for months or longer. Avoid further injury to the area to reduce the development of new lesions.2

Do not squeeze, scrape or puncture milia at home: you can cause infection or permanent scars. Professional removal involves making a small opening in the surface and extracting the contents. The opening is part of the procedure, not an invitation to press harder on a closed bump.34

For widespread milia, a topical retinoid may help. A clinician can also consider freezing or other procedures for extensive cases. For home care, wash daily with warm water and gentle soap, pat dry and use sunscreen outdoors.23

When should you get the bumps checked?

Arrange an assessment if suspected milia worsen or do not improve after a few months, or if you want them removed. Deep, painful acne bumps need a dermatologist's help because they can leave permanent scars. Bumps around the eyes are not always milia: other cysts and growths can look similar, so an examination is useful before choosing treatment.237