What are blackheads?
Blackheads are blocked sebaceous (oil) glands. They are seen in acne, but can also occur spontaneously without acne being present. The official name for a blackhead is a comedo. They are seen mainly on parts of the skin that are rich in sebaceous glands, such as the face, the chest and the upper back.
Types of comedones
Open comedones. This type is also called blackheads. The dried sebum lies in an open pore and has turned black through oxidation at the skin surface, where it is exposed to the air.
Closed comedones. With these (also called whiteheads) the skin is still closed and the sebum has not yet dried out or oxidised. The white sebum shows clearly through the skin.
Micro-comedones. These are small comedones that can sometimes still grow into larger ones. They can be either open or closed.
Giant comedones. These are very large comedones with a large black plug in the middle. They are not rare and are seen mainly on the back in adults.
Conditions in which comedones can occur
Acne. This is by far the largest group. In classic acne (acne vulgaris) the different comedones (whiteheads and blackheads) occur mixed together on the skin.
Favre-Racouchot syndrome. In this condition groups of small open comedones develop on the face, especially around the eyes and on the cheeks; these are also called solar comedones. The condition is seen mainly in older people, and a lot of past sun exposure and smoking increase the chance of developing them.
Hidradenitis. In this condition there are severe, deep inflammations of the sebaceous glands in the skin folds (armpits, groin, under the breasts, abdominal fold), where tracts under the skin can also form. Comedones can occur here too.
Naevus comedonicus. This is a rare type of birthmark that is made up not of pigment cells but of comedones — a developmental disorder of the sebaceous glands occurring in a group, forming a “comedo birthmark”.
How can comedones be treated?
Squeezing out. Comedones can be “emptied” by carefully pressing them out, either with the fingers or with a special kind of small loop. As a rule it is wisest to leave this to a beautician or skin therapist rather than removing them yourself, because unintended damage to the skin can cause small wounds and, ultimately, small scars. Real acne spots must be treated carefully: if careless squeezing pushes sebum not only to the surface but also through the inflamed gland wall into the skin, a considerable inflammation will occur as the immune system reacts to the sebum lying free in the skin.
Cream therapy. Some anti-acne creams can be effective in treating comedones and preventing them. Examples of these topical treatments are benzoyl peroxide and tretinoin cream. Among other things, they cause a mild peeling of the skin so that the pores become blocked less quickly. Tretinoin may also influence the production of the sebum itself.
Preventing comedones
- Do not use greasy cosmetic products that block the pores.
- Remove make-up from the face every day.
When to see a doctor
See your GP or a dermatologist if blackheads and whiteheads are accompanied by inflamed spots, deep painful lumps or scarring, or if over-the-counter creams do not help after some weeks. In older people, prompt assessment is wise for any single spot that grows, bleeds or does not heal, as not every dark spot is a harmless comedo.