Seborrheic dermatitis

What is seborrheic dermatitis?

Seborrheic dermatitis is an inflammatory skin condition that causes patches of scaly skin. These patches might be dry, scaly and greasy, or both.

Seborrheic dermatitis is most common on oily areas of skin like the scalp, face, ears, beard, or chest – but it can occur anywhere aside from the palms of your hands and soles of your feet.

Who gets seborrheic dermatitis?

Seborrheic dermatitis can affect anyone, regardless of age, ethnicity, or sex. But babies between one week and six months old, and adults over 40 years old are more likely to be affected. There’s not enough evidence as of now to link getting seborrheic dermatitis as an infant with developing it as an adult.^[1]

You’re also more likely to develop seborrheic dermatitis if you have HIV-AIDS, or neurological problems like Parkinson’s, dementia, or stroke^[1].

How common is seborrheic dermatitis?

Seborrheic dermatitis is a common skin condition, with around five percent of the global population living with it. But non-inflammatory seborrheic dermatitis, commonly called dandruff, is much more common – around 50%.^[1]

A study in Australian preschools showed seborrheic dermatitis affected 72% of three month old children, which then fell quickly as they grew older. About 14% of middle-aged adults have seborrheic dermatitis according to analysis of the Rotterdam Study data, but this increases to 35% in people with HIV, and 85% in those with AIDS.

What causes seborrheic dermatitis?

Seborrheic dermatitis can occur for lots of different reasons, but we don’t fully understand why it happens. Some commonly suggested seborrheic dermatitis causes are:

• Environmental triggers (cold weather, low humidity, etc.);
• Fungal infection by Malessezia spp.;
• Activity of the sebaceous gland;
• Immunosuppression;^[2]
• Disruption of microorganisms on your skin;
• More unsaturated fatty acids present on your skin.^[1]

What are the symptoms of dermatitis?

Seborrheic dermatitis symptoms can affect you differently depending on the tone of your skin, how old you are, and any other medical conditions you might have. The most common symptoms of seborrheic dermatitis are:

• A rash on your scalp or face. This tends to look red and raised on lighter skin tones – or light pink or purple with white spots on darker skin tones. The skin might be dry or have oily scales, or a combination of both;
• Dry, scaly, flaky skin. You can get dry, flaky scales of skin anywhere you have seborrheic dermatitis;
• Itching and burning sensation. Usually this is mild, and can be treated with medicine;
• A rash on your eyelids. Inflamed oil glands in your eyelids can cause blepharitis, causing them to become itchy, discoloured, swollen, scaly and irritated.
• Rash on the ear. You might also get inflammation in or around your ear. This can cause flaking, crusting, your skin to crack, or oozing from your ear.

Can seborrheic dermatitis cause other problems?

Seborrheic dermatitis can cause hair loss due to inflammation and itching on your scalp. Scratching the rash caused by seborrheic dermatitis can cause damage to your hair follicles, disrupting your hair’s natural growth and causing it to fall out. Luckily, you can get treatment that can reduce or stop any itching.

If it isn’t treated, the broken or damaged skin caused by seborrheic dermatitis can become infected by fungus or bacteria. This can make symptoms like discolouration, tenderness, and weeping worse – so it’s really important to keep your condition under control.