Dandruff, also known as seborrhea, is a chonic skin condition that occurs primarily on the scalp, but can also occur on other parts of the body. The primary symptoms are a red, itchy rash and white scales in the affected area. Scalp dandruff may also cause oily flakes to fall on the shoulders, upper back and chest. Dandruff is composed primarily of dead skin, but may also contain a fungus called Malassezia.
Dandruff and Dead Skin
Skin is made of several layers of cells known as epithelial cells. The skin is constantly renewing itself and, as new cells grow, they push older cells to the surface until the flake off. According to Kid's Health, we lose as many as 40,000 skin cells per day, and up to 95 percent of the lives cells in the skin are devoted to making new cells. With dandruff, the skin cells die, clump together and fall off at a higher rate than normal. While there is no cure for dandruff, it is easily treated with daily washing or over-the-counter dandruff treatments, such as coal tar or salicylic acid.
Dandruff and Sebum
Sebum is the oil that the hair follicle produces to moisturize the hair and scalp. If these oils sit on the scalp, they can cause irritation that stimulates cell growth, resulting in dandruff. This type of dandruff contains dead skin cells and sebum and responds well to daily washing and over-the-counter dandruff treatments.
Dandruff and Malassezia
Malassezia is a yeast-like fungus that feeds on sebum. According to the Mayo Clinic, malasezzia exists on most adult scalps and only becomes a problem when it grows out of control and irritates the scalp. This scalp irritation stimulates skin cell growth and results in dandruff. People with this form of dandruff may have malassezia spores, in addition to dead skin in their dandruff flakes. This form of dandruff responds to daily washing, over-the-counter or prescription dandruff treatments.
Dandruff and Psoriasis
Psoriasis is similar to dandruff in that it causes the skin to shed large amounts of skin cells. Unlike dandruff, however, psoriasis is caused by the immune system stimulating excess cell growth, as opposed to factors on the surface of the skin. Psoriasis may exhibit the same flaking as dandruff, and the flakes should only contain dead skin. According to the Mayo Clinic, psoriasis may respond to topical or oral steroids as well as over-the-counter dandruff treatments.
Dandruff and Tinea Capitis
Tinea capitis, also known as ringworm of the head, is a contagious fungal infection of the scalp. Unlike malassezia, the tinea fungus is not naturally occurring and may be caused by exposure to the fungus, such as by sharing hats or hair-styling tools. Tinea capitis may be confused for dandruff because it has similar symptoms, such as skin irritation, itching and flakes. Unlike dandruff, tinea capitis only responds to prescription antifungal treatments. Tinea capitis flakes may have the tinea fungus in addition to dead skin.
