Skin all over the body is made up of various layers, but skin in certain places feels and behaves differently. Our scalps are made up of five layers with only the outer layer actually being skin. The first three layers: skin, connective tissue and the layer where muscles attach, are bound together as a single unit. The next layer is only loosely connected and allows our scalps to move around on our heads as well as creating a space for blood vessels and nerves to pass. The last layer lines the bones of our skulls.
Scalp skin is some of the thickest skin in the body as it carries more blood than skin in other places. This abundance of blood vessels is why we bleed so easily when something injures our scalp. A scalp hematoma or “goose egg” can form if blood pools in the space between the skin and the muscle layer from a blow to the head. If this occurs, a medical exam should be done to ensure that there is not further damage to the brain.
In addition to growing head hair, scalp skin is different because it has more sebaceous (oil) glands than other skin areas. This increased amount of oil can cause a range of scalp conditions such as: sebaceous cysts, scalp acne, seborrhea dermatitis or dandruff.
Sebaceous cysts are non-cancerous pocketed bumps that are filled with fatty material called keratin and old cells. They can be extremely tender and possibly need to be drained or removed if they become enlarged.
Scalp acne can be caused by a variety of reasons including: stress, hormones, diet, heredity, and excess caffeine in addition to poor hygiene and excess oil accumulation. One of the concerns of having scalp acne is that it can contribute to hair loss. Use of oil based hair products can aggravate scalp acne.
Seborrhea dermatitis is thought to be caused from excess skin oil along with an overgrowth of a yeast called malessizia. White or yellow scales develop on the scalp that flake and are extremely itchy. Seborrhea dermatitis can resemble scalp psoriasis so must be evaluated by a dermatologist to decide treatment.