Acne is a skin condition affecting the hair follicles, mainly of the face, but also of the chest, back, and in rare cases, the scalp. Acne is most often seen during the teenage years but may also occur later in life. Overstimulation of the sebaceous glands attached to the hair follicles by androgens (male hormones) is one of the most common causes of acne.
How does Scalp Acne Form?
Scalp acne forms in much the same way as acne in any other part of the body. The sebaceous or oil glands are located deep in the skin and each oil gland is connected to a follicle, which is a tiny canal containing a hair. The oil or sebum produced by the sebaceous glands flows out through the follicle to the skin surface. This helps to lubricate the hair follicles and the skin. The opening of the follicle on the skin surface is known as a pore.
Acne forms as a result of a combination of 3 factors
- Excess oil or sebum production.
- Blocked pores.
- Inflammation caused by bacteria.
Acne forms when an overactive sebaceous gland produces excess oil, which may then get trapped within the blocked pores. The exact cause of blocked pores is not known. As a result of this blockage, the hair follicle may enlarge to form a little bump and in time it may rupture, thus allowing bacteria to reach deep into the tissues and cause inflammation. Normal skin bacteria, Propionibacterium acnes (P. acnes) multiply within the blocked pores and causes inflammation of the follicle. Acne is not caused by bacterial infection but bacteria may play a role in its development. Whiteheads, blackheads, painful red bumps (pimples), pustules, cysts, and boils develop as a result of pore blockage.
Superficial inflammation results in pustule formation, while deeper inflammation causes pimples, and still deeper ones result in cyst formation. Whiteheads are formed when the excess oil comes out on the surface, while blackheads are formed by oxidation of the oil, and not by accumulation of dirt as is commonly thought.
What Causes Scalp Acne?
Many factors may contribute to scalp acne :
- Hormones, especially during adolescence and at times of menstruation.
- Hot, humid conditions.
- Environmental factors, such as pollution.
- Exposure to certain chemicals and oils.
- Certain drugs, such as corticosteroids, lithium, and estrogen or androgen containing medication.
- Oily, greasy scalp.
- Friction or pressure, as from helmets.
- Hair products such as hair oils, conditioners, and gels can cause blocked pores.
- Acne tends to run in families.
Fatty food, chocolate, and nuts do not cause acne.
Symptoms of Scalp Acne
Scalp acne may not always be noticeable since the scalp is covered by hair. Touching it accidentally while combing or brushing may cause pain and only then be discovered.
- Mild scalp acne may be seen in the forehead region, near the hair line.
- Infection of the hair follicle can cause scalp folliculitis, which is a more severe condition.
- Scalp acne may be considered to be a non-infectious form of scalp folliculitis.
- Acne necrotica miliaris is a more severe but rarer form of scalp folliculitis which is seen as tiny superficial pustules. As well as affecting the scalp it may also develop on the face and other parts of the body. Picture below of acne necrotica.
- Pomade acne is seen more commonly in people who use oily hair care products. It may be seen around the hairline in the forehead and temples.
- Acne keloid is mainly seen around the hairline at the back of the scalp as a thick band.
- Small itchy pustules.
- Red bumps may be seen on the scalp.
- Crusting and oozing.
- Matting of the hair.
- Bald patches and scarring if left untreated for long.
Picture of Acne Necrotica (Source : Dermatology Atlas, Courtesy of Samuel Freire da Silva, M.D.)
Treatment of Scalp Acne
Treatment sometimes becomes difficult due to hair on the scalp interfering with local application of an ointment or lotion. Scalp acne may resolve on its own (rarely) or with over-the-counter applications. Medical treatment should be sought if it is persistent or progressing.
- Shampooing the hair frequently with a gentle shampoo to eliminate excess oil.
- Benzoyl peroxide is often used for acne elsewhere in the body but is not suitable for scalp acne since it can bleach the hair.
- Salicylic acid, in shampoos or creams.
- Oral medication should be used if scalp acne does not respond to topical applications.
- Topical and oral antibiotics in case of infection.
- Isotretinoin may be used in persistent and severe cases of scalp acne. Treatment has to be long term and it may have certain unwanted side effects.