What is seborrheic dermatitis?
Seborrheic dermatitis is a common, noncontagious, easy-to-manage skin condition. This type of dermatitis causes itchy red patches and greasy scales on your skin along with white or yellow crusty or powdery flakes on your scalp.
“Seborrheic” refers to the “sebaceous” glands while “derm” means “skin.” It’s called “dandruff” (pityriasis capitis) when it’s on a teenager’s or adult’s scalp, and “cradle cap” when it’s on a baby’s.
Seborrheic dermatitis can occur in other areas of your body. These are areas with the most sebaceous (oil) gland activity: your upper back and chest, face/forehead, the creases at the base of your nose, behind your ears, navel (belly button), eyebrows, under your breasts and in the creases/bends of your arms, legs and groin.
Seborrheic dermatitis is a lifelong condition that appears, disappears with treatment, and flares up from time to time.
Who gets seborrheic dermatitis?
About 11% of the population has seborrheic dermatitis. It occurs most often in infants younger than three months old and in adults ages 30 to 60. It is more common in men than in women, and in Caucasians more than African Americans.
If you are born with naturally oily skin, you are more likely to get this type of dermatitis. A history of psoriasis in your family makes you vulnerable as well. If you live in a dry, cold region, the weather doesn’t cause the seborrheic dermatitis, but it does make it worse.
If you have these health issues, you’re more prone to seborrheic dermatitis:
- Organ transplant recipients.
- Adult Hodgkin’s Lymphoma.
- Adult Non-Hodgkin’s Lymphoma.
- HIV (human immunodeficiency virus).
You’re also more prone to seborrheic dermatitis if you take these psychotropic medications:
- Haloperidol decanoate.
What are the symptoms of seborrheic dermatitis?
- Itchy white flakes of skin on your scalp (dandruff). When scratched, the flakes come loose, mix in with your hair, or fall onto your neck and shoulders.
- Red scales on your skin.
- Crusty yellow scales on infants’ heads (cradle cap). Cradle cap shouldn’t itch, but scratching may cause additional inflammation in the area and break the skin, leading to bleeding or mild infections.
- Blepharitis (scaly redness on the edges of your eyelids).
- Pinkish plaques (thick skin) of scales on both sides of your face.
- Flaky patches on your chest and at your hairline that are shaped like a flower petal or a ring.
- Redness in the folds and creases of your genitals, armpits and beneath your breasts.
- Inflamed hair follicles on your cheeks and the upper half of your trunk.
What are the causes of seborrheic dermatitis? What aggravates it?
Researchers aren’t sure of the exact cause of seborrheic dermatitis. They think there may be many causes. Factors that are thought to play a role include:
- A type of yeast called Malassezia, which is present on everyone’s skin, but overgrow in some people.
- An increased level of androgens (a hormone).
- An increased level of skin lipids.
- An inflammatory reaction.
- Family history (dermatitis runs in the family).
Other factors that trigger or worsen seborrheic dermatitis include:
- Cold and dry climate.
- Oily skin.
- Using alcohol-based lotions.
- History of other skin disorders, including rosacea, psoriasis and acne.
Does the weather make seborrheic dermatitis worse?
Dry air during the winter months will make your seborrheic dermatitis worse.
The dermatitis behaves best during the summertime. The sun’s UV-A and UV-B light have been shown to kill the type of yeast that overgrows on the skin of people who get seborrheic dermatitis. Just watch out for sunburns!
Do certain foods trigger or reduce seborrheic dermatitis?
Although there are theories out there, true experts have yet to find that food causes or reduces seborrheic dermatitis. Diet does not affect dandruff.
What's the difference between seborrheic dermatitis and psoriasis?
Psoriasis and seborrheic dermatitis can mimic each other. Both are patches of red skin with flakes. Both can be found on your scalp and back.
Psoriasis is an inflammatory skin disease that affects 2% to 4% of the population. The scales of psoriasis are often thicker than that of seborrheic dermatitis. The edges of those scales are very well-defined. On the scalp, psoriasis scales are closer to a silver color than white or yellow.
There is a condition called sebopsoriasis where seborrheic dermatitis and psoriasis overlap. In that case you have the symptoms of both: both white flakes and silver flakes, both on the scalp or back, both itchy.
If you’re concerned about whether you have psoriasis or seborrheic dermatitis, consult your healthcare provider. Treatment for one may not work as treatment for the other.
Does seborrheic dermatitis cause hair loss?
No, seborrheic dermatitis does not cause hair loss.
Is seborrheic dermatitis related to acne?
Seborrheic dermatitis and acne can appear at the same time, in the same places on your body. Both are affected by oils in your skin. People who have acne are more likely to have dandruff.