Seborrheic dermatitis is a type of eczema that causes itchy patches, rashes, and dandruff. The face, scalp, and chest are commonly affected areas. Researchers don’t know exactly what causes the skin condition, but an overgrowth on the skin of a yeast called Malassezia may play a role.

Seborrheic dermatitis is linked to several risk factors, or factors that increase a person’s chance of developing it. Some risk factors include genetics, certain health conditions, or medications.

Here, we explore the relationship between Malassezia yeast and seborrheic dermatitis and other risk factors involved in the development of the skin condition.

Sebaceous Glands and Malassezia Yeast

Scientists haven’t found a single, clear cause of seborrheic dermatitis. They believe it’s caused by a combination of factors.

Almost all parts of the skin — except for the palms of your hands and the soles of your feet — have sebaceous glands. These glands make sebum, an oil that keeps your skin moisturized and protects it from bacteria and viruses. Seborrheic dermatitis symptoms tend to show up in areas with more sebaceous glands, such as the scalp, face, armpits, folds of the legs and groin, and behind the ears.

Malassezia yeast is a type of yeast that naturally lives on everyone’s skin. It’s often found in the sebum on areas of skin affected by seborrheic dermatitis. Because antifungal medications that reduce yeast overgrowth also help reduce seborrheic dermatitis symptoms, scientists think there may be a strong link between Malassezia yeast and seborrheic dermatitis.

Current research suggests that Malassezia yeast isn’t the only cause of seborrheic dermatitis. Instead, it seems to work with other factors — like an impaired skin barrier and an overactive immune system response — to cause the inflammation seen in seborrheic dermatitis.

Gene Changes and Protein Abnormalities

Inherited risk factors are passed down from parents to children. Researchers believe that some inherited gene changes may contribute to the development of seborrheic dermatitis.

Researchers have found 11 different gene changes and protein deficiencies that are linked to seborrheic dermatitis. These changes affect the immune cells in the skin, preventing them from working properly. When that happens, the skin becomes more sensitive to things like yeast overgrowth, which can trigger inflammation and rashes.

One study found that certain HLA proteins may lead to an increased risk of seborrheic dermatitis. These proteins are found on the outside of your cells (except red blood cells). Their job is to tell your immune system which cells belong to your body and which ones don’t.

Another study of people with seborrheic dermatitis, acne, psoriasis, and eczema found that certain gene changes may be linked to the development of these conditions.

Family History

If someone in your family has seborrheic dermatitis or another inflammatory skin disorder, your chances of developing seborrheic dermatitis are higher too.

Age

According to the American Academy of Dermatology, anyone can develop seborrheic dermatitis. However, it’s much more likely to affect babies between 2 and 12 months old (often called cradle cap) and may develop in early to middle adulthood. Adolescents going through puberty may also develop seborrheic dermatitis.

Sex

Seborrheic dermatitis tends to affect men more often than women, according to the American Academy of Dermatology.

Other Health Conditions

Certain health conditions can increase your risk of developing seborrheic dermatitis directly, but they don’t cause it directly. You may have a higher risk of the skin condition if you also have:

• Conditions that affect the immune system, like human immunodeficiency virus (HIV), adult non-Hodgkin lymphoma, and adult Hodgkin lymphoma
• An organ transplant
• Neurologic disorders like Parkinson’s disease, epilepsy, and tardive dyskinesia
• A stroke or heart attack
• Alcohol use disorder
• Psoriasis
• Rosacea

Seborrheic dermatitis is more common in people with weakened immune systems, including those living with HIV or acquired immunodeficiency syndrome (AIDS). Studies show that about 85 percent to 95 percent of people living with late-stage HIV experience this skin condition. Symptoms also tend to be more severe in people with HIV/AIDS and may appear on parts of the body that aren’t usually affected.

According to the American Parkinson Disease Association, people with neurological diseases such as Parkinson’s disease are also more likely to have seborrheic dermatitis. Parkinson’s disease affects the autonomic nervous system, which can affect how the sebaceous glands work. Because of this, people with Parkinson’s disease tend to have oily skin on the face and scalp, which can lead to seborrheic dermatitis symptoms.

Not everyone with these health conditions will develop seborrheic dermatitis. Often, treating these conditions can help improve seborrheic dermatitis symptoms. If you have seborrheic dermatitis and another ongoing medical condition, talk to your doctor or dermatologist about the best way to manage both.

Mental Health Conditions

People with mental health conditions such as anxiety, eating disorders, and depression may also be more likely to develop seborrheic dermatitis. Living with a visible skin condition can also make these mental health conditions worse, creating a cycle of stress and flare-ups.

Stress doesn’t directly cause seborrheic dermatitis, but it can often trigger or worsen seborrheic dermatitis flares.

Medications

Some medications can also cause a seborrheic dermatitis-like skin reaction as a side effect, including:

• Dopamine antagonists — Used to treat Parkinson’s disease
• Lithium — Used to treat mental health conditions
• Immunosuppressants — Used for managing inflammatory diseases
• Immunomodulators like interferon — Used to boost the immune system in people with autoimmune disorders, cancer, and other conditions
• Psoralen/psoralen and ultraviolet A (PUVA) — Used to treat psoriasis
• Psychotropic medications — Drugs such as buspirone, haloperidol decanoate, and chlorpromazine, used to manage mental health conditions

If you take one of these medications and notice symptoms of seborrheic dermatitis — such as dry, itchy, or flaky skin — talk to your healthcare provider. They may adjust your dosage. switch you to a different medication, or suggest additional treatments to help relieve your skin symptoms.

Can Seborrheic Dermatitis Be Prevented?

Unfortunately, you can’t prevent seborrheic dermatitis. It can be a chronic (lifelong) skin disease that tends to come and go. However, symptoms can be well-managed by avoiding triggers, using over-the-counter treatments like shampoos, and working with a healthcare provider to find an effective seborrheic dermatitis treatment.

While Malassezia yeast may play a role in the development of seborrheic dermatitis, many other factors can increase the risk of the condition. By working with a healthcare provider to understand what might be causing your skin symptoms, you can better manage the skin condition and find treatments that work for you.

Join the Conversation

On MySebDermTeam, people share their experiences with seborrheic dermatitis, get advice, and find support from others who understand.

Do you have other health conditions related to your seborrheic dermatitis? Let others know in the comments below.