Despite its appearance, this skin disease is not caused by poor hygiene. This is a very common skin disease that causes a rash. When this rash appears, it often looks like the one pictured above.
The skin tends to have a:
Reddish color.
Swollen and greasy appearance.
White or yellowish crusty scale on the surface.
One or more of these rashes can appear on the body. Sometimes, the affected skin itches.
Cradle cap: A type of seborrheic dermatitis
Many infants get cradle cap. This is a type of seborrheic dermatitis (seb-uh–ree-ick dur-muh–tahy-tis) that develops in babies. Scaly, greasy patches form on the baby’s scalp. The patches can become thick and crusty, but cradle cap is harmless. Cradle cap usually goes away on its own within a few months.
Babies also get seborrheic dermatitis in their diaper area and elsewhere. In the diaper area, the red rash often is mistaken for diaper rash. A few babies get seborrheic dermatitis that covers much of the body with red, scaly patches.
No matter where the seborrheic dermatitis forms, it tends to permanently disappear between 6 months and 1 year of age.
Seborrheic dermatitis is long-lasting in adults
When an adult gets seborrheic dermatitis, the condition can come and go for the rest of the person’s life. Flare-ups are common when the weather turns cold and dry. Stress also can trigger a flare-up. The good news is that treatment can reduce flare-ups and bring relief.
Reddish, oily-looking patches often appear on the scalp and face.
Symptoms
The signs and symptoms of seborrheic dermatitis vary with age. The following describes how it affects people at different ages.
A patch of seborrheic dermatitis on a man’s scalp.
The pinkish skin on this woman’s forehead, eyelids, and nose is seborrheic dermatitis.
When a person is HIV positive, seborrheic dermatitis is often widespread.
People with Parkinson’s disease often have widespread seborrheic dermatitis, as shown here.
Adults and adolescents
Seborrheic dermatitis causes:
Scaly patches on the skin.
The skin beneath these patches is reddish.
Although scaly, patches often look greasy or moist.
Scales can flake off and tend to be yellowish to white.
In adults and adolescents, the skin can:
Itch, especially on the scalp and in the ear canal.
Burn.
Patches form where the skin is oily:
Scalp.
Ears (around and in the ear canal).
Eyebrows (the skin beneath).
Center of the face.
Eyelids.
Upper chest.
Upper back.
Armpits.
Genitals.
Patches form where the skin is oily, such as on the scalp, face, and in the ear canals.
Infants
When an infant gets seborrheic dermatitis, it tends to form on the scalp and is known as cradle cap.
Signs and symptoms of cradle cap include:
Yellow, greasy scale on the scalp.
A thick layer of scale can cover the entire scalp.
Scale is often yellow to brownish in color.
With time, the scale becomes flaky and easily rubs off.
In infants, seborrheic dermatitis also can form on the face, usually on a baby’s eyelids, around the nose, or ears. It also forms in the diaper area. In a few babies, seborrheic dermatitis covers most of the body.
Most infants seem unbothered by seborrheic dermatitis. Cradle cap sometimes itches.
Causes and Risk Factors
What causes seborrheic dermatitis?
Researchers are still studying what causes this common skin disease. From what they have learned, it appears that the cause is complex. Many factors seem to work together to cause seborrheic dermatitis. These factors may include the yeast that normally lives on our skin, our genes, living in a cold and dry climate, stress, and a person’s overall health.
By studying seborrheic dermatitis, researchers have learned the following:
It is not caused by poor personal hygiene.
It is not an allergy.
It does not harm the body.
Who gets seborrheic dermatitis?
People of all colors and ages get seborrheic dermatitis. You have a higher risk if any of the following apply to you.
People in these two age groups are most susceptible:
Infants 3 months of age and younger.
Adults between 30 and 60 years of age.
Your risk increases if you have any of these medical conditions:
HIV (About 85 percent of people infected with HIV develop seborrheic dermatitis).
Acne, rosacea, or psoriasis.
Parkinson’s disease.
Epilepsy.
Stroke or heart attack (recovering from).
Alcoholism.
Depression.
Eating disorder.
If you are taking any of the following medicines, your risk for seborrheic dermatitis increases:
Interferon.
Lithium.
Psoralen.
Diagnosis and Treatment
Seborrheic dermatitis is a condition that dermatologists frequently diagnose and treat.
If you think you might have seborrheic dermatitis, you should see a dermatologist for a diagnosis. This common skin condition can look like psoriasis, eczema, or an allergic reaction. Each of these skin diseases requires different treatment.
Diagnosis
A dermatologist diagnoses seborrheic dermatitis by:
Reviewing the patient’s medical history.
Examining the patient’s skin and looking closely at the rash.
Sometimes seborrheic dermatitis is a sign of an underlying medical condition. If your dermatologist suspects this, medical tests may be necessary.
Treatment
Although treatment cannot cure seborrheic dermatitis, treatment has benefits. Treatment can loosen and remove scale, prevent a skin infection, and reduce swelling and itch.
The type of treatment a dermatologist prescribes varies with age and where the seborrheic dermatitis appears on the skin.
Infants (scalp): Called cradle cap, this tends to completely disappear without treatment. If treatment is necessary, a dermatologist may recommend:
Shampooing the baby’s scalp daily with a baby shampoo.
Gently brushing away the scale, once scale starts to soften.
Applying a medication to the infant’s scalp.
Infants (skin beyond the scalp): This, too, will clear. If treatment is needed, a dermatologist may prescribe a medicine that can be applied to the child’s skin.
Adolescents and adults (scalp and rest of body): After infancy, seborrheic dermatitis usually does not go away without treatment. For the best results, a dermatologist will consider many factors before creating a treatment plan.
Treatment may include:
Dandruff shampoos.
Medicine to apply to the skin for short periods of time.
Barrier-repair cream.
Dandruff shampoos can be helpful on the skin as well as the scalp. Your dermatologist can explain how to use these shampoos on the skin.
Often the best results come from combining two or more treatments. Your dermatologist can create a treatment plan to meet your needs. Most plans include medication and skin care.
Always follow your dermatologist’s instructions. Using a treatment more often than prescribed or longer than prescribed can cause side effects.
Outcome
Infant: Seborrheic dermatitis often completely disappears by 6 months to 1 year of age. It can return when the child reaches puberty.
Adolescent or adult: A few people see seborrheic dermatitis clear without treatment. More often, seborrheic dermatitis lasts for years. It tends to clear and flare without warning. Treatment often is necessary to control it.
References
Images used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides.
Habif TP, Campbell JL, et al. “Seborrheic dermatitis.” In: Dermatology DDxDeck.China, Mosby Elsevier: 2006, p. 40.
Plewig G Jansen T. “Seborrheic Dermatitis.” In: Wolff K, Goldsmith LA, Katz SI, et al. editors. Fitzpatrick’s Dermatology in General Medicine, 7th ed. United States of America, McGraw Hill Medical; 2008. p.219-25.
