Seborrheic dermatitis is a chronic (ongoing) skin condition that often occurs alongside other skin diseases. It’s also diagnosed at higher rates in people with impaired immune systems and some neurological diseases. Recognizing and treating these other conditions may help ease seborrheic dermatitis symptoms too. Here are six medical conditions people with seborrheic dermatitis may also experience.

Seborrheic Dermatitis Comorbidities and Complications

The term “comorbidity” describes having two or more health conditions at the same time. People with seborrheic dermatitis may experience comorbidities such as other skin conditions, Parkinson’s disease, human immunodeficiency virus (HIV), AIDS, metabolic syndrome, and high blood pressure.

Sometimes, health conditions can lead to other medical problems, and these are called complications. Although seborrheic dermatitis can cause complications, they are usually minor and can be treated.

1. Parkinson’s Disease

Seborrheic dermatitis is more common in people with neurological disorders like stroke or Parkinson's disease. It occurs in about 50 percent of people with Parkinson’s. Researchers don’t fully understand why people with Parkinson’s and other neurological disorders experience more seborrheic dermatitis, but there are some theories.

Parkinson’s disease affects the autonomic nervous system, which controls bodily functions like heart rate, breathing rate, and the production of oil from the skin’s sebaceous glands (oil glands). In people with Parkinson’s, the impaired ability to regulate oil production can lead to excess oil on the skin and symptoms of seborrheic dermatitis.

Seborrheic dermatitis and Parkinson’s disease may also be connected through the body’s reaction to Malassezia yeast. Studies show that this type of yeast may play a role in the development and progression of Parkinson’s. Malassezia yeast is also thought to be a potential factor in the development of seborrheic dermatitis. Some studies suggest that having seborrheic dermatitis increases a person’s risk of developing Parkinson’s.

If you have Parksinson’s disease and develop skin symptoms, talk to your doctor or a dermatologist to find out if you might have seborrheic dermatitis.

2. HIV and AIDS

People with HIV or AIDS are also more likely to have seborrheic dermatitis. Researchers estimate that around 35 percent of people with early HIV infection and 85 percent of those with AIDS develop seborrheic dermatitis. The reason for this increased risk isn’t fully understood, but it might be due to the fact that people with HIV or AIDS have a weakened immune system.

HIV affects the body’s immune system by infecting and killing a specific type of immune cell known as CD4-positive T cells. Seborrheic dermatitis typically develops when a person’s CD4-positive T cell count drops between 201 and 500 cells per cubic millimeter of blood — normal counts are between 500 and 1500 cells per cubic millimeter.

A weakened immune system can’t fight off infections as easily. Those living with HIV or AIDS don’t have the CD4-positive T cells required to control the natural growth of yeast on the skin, which can lead to yeast overgrowth, fungal infections, and worsening of seborrheic dermatitis symptoms.

Seborrheic dermatitis has also been found to be more severe in people with HIV and may require a longer course of treatment. If you have HIV or AIDS, it’s good to be aware of this connection and bring up any skin symptoms you experience to your doctor.

3. Metabolic Syndrome and Hypertension

Metabolic syndrome is a potential comorbidity of seborrheic dermatitis. Researchers are still learning about the link between the two conditions, but studies show that they may be connected through chronic inflammation.

The term “metabolic syndrome” refers to a group of health conditions that increase a person’s risk of serious health complications such as diabetes, stroke, and heart disease. These conditions include:

• Hypertension (high blood pressure)
• High blood sugar caused by insulin resistance
• High levels of “bad” cholesterol (particularly low-density lipoprotein, or LDL)
• Low levels of “good” cholesterol (high-density lipoprotein, or HDL)
• Extra fat around your waistline

Many people with metabolic syndrome have chronic low-grade inflammation, which can cause other diseases. For example, psoriasis has been found to occur alongside metabolic syndrome. In fact, studies have shown that metabolic syndrome is three times more common in people with psoriasis than in the general population. Because of similarities between psoriasis and seborrheic dermatitis, researchers have also looked into the relationship between seborrheic dermatitis and metabolic syndrome.

One small study found connections between seborrheic dermatitis and lower levels of HDL, a beneficial type of cholesterol. A different study with over 18,000 participants — about half had seborrheic dermatitis and half did not — found that hypertension was more common in people with seborrheic dermatitis than in those who didn’t have the skin condition. Researchers believe this is due to a combination of genetic factors and the cytokines (small proteins involved in the immune system) that are overactive in this chronic skin inflammation. The research continues, but some existing studies show that metabolic syndromes may be a comorbidity of seborrheic dermatitis.

4. Skin Conditions

People with seborrheic dermatitis are at a higher risk of developing and living with other dermatological or skin diseases. To help tell these conditions apart, your dermatologist may do a skin biopsy (remove a tissue sample so it can be examined more closely) when diagnosing you. It’s possible to have seborrheic dermatitis and at least one of the following skin conditions:

• Atopic dermatitis — Itchy, inflamed, dry skin
• Contact dermatitis — Allergic reaction to a substance that causes a rash
• Acne — Chronic skin condition in which hair follicles become clogged with oil and dead skin cells
• Psoriasis — Rash with scaly, itchy patches of skin
• Blepharitis — Dry skin, scaling, and redness along the eyelids and eyelashes
• Malassezia folliculitis — Infection of the hair follicles with Malassezia yeast
• Tinea — A group of contagious fungal infections (also called pityriasis versicolor)
• Folliculitis — Infection of the hair follicles
• Onychomycosis — Fungal infection of the fingernails and toenails
• Intertriginous dermatitis — Inflammation and red or reddish-brown rash in skin creases and folds due to friction, heat, or moisture
• Extragenital warts — Noncancerous growths caused by HPV infection
• Pyoderma — Painful skin sores usually found on the legs
• Rosacea — Red (flushing) or brown discoloration in the face, depending on natural skin tone, possibly with acnelike lesions

Whether you’ve already been diagnosed or just started experiencing skin symptoms, it’s a good idea to check with a dermatologist to see if you might have more than one skin condition, as many can overlap. Different conditions may require different treatments. For example, a corticosteroid may help your seborrheic dermatitis, but an antifungal may be needed for onychomycosis.

Before you see a health care provider, try keeping a daily journal to track your symptoms and how they change. You could also take pictures of your affected areas to help you better show and explain your symptoms to your doctor.

5. Bacterial and Fungal Infections

During seborrheic dermatitis flares, the skin becomes inflamed. You may develop rashes, usually in skin folds in areas like the armpits, groin, and under the breasts. Without treatment, you could develop secondary (arising after your seborrheic dermatitis) bacterial or fungal infections like yeast infections. If your skin becomes red and itchy after using seborrheic dermatitis treatments, talk to your doctor about whether you might have an infection.

To help prevent skin infections, you can:

• Wash your hands regularly, including before applying skin care medication or moisturizer.
• Take bleach baths up to three times a week to kill any bacteria on your skin. Make sure you properly dilute the bleach — use a quarter cup of bleach in a full bathtub of water — and soak in the tub for only about 10 minutes. Apply plenty of moisturizer afterward.
• Use a tool like a metal spoon to scoop out an application of a topical cream or lotion — dipping your fingers in the container could spread bacteria.
• Be alert for signs of an infection, such as weeping (oozing fluid) or warm skin, blisters, soreness, or a fever, and tell your doctor right away if these symptoms appear.

If you get frequent skin infections, ask your doctor about ways you can better prevent them, like using an antiseptic wash.

6. Mental Health Disorders

Living with seborrheic dermatitis can also affect your mental health and overall quality of life. Like others living with skin diseases, people with seborrheic dermatitis often experience anxiety and depression. According to a study in the journal Mycoses, women and adolescents with the condition tend to report poorer quality of life.

Not everyone with seborrheic dermatitis experiences mental health complications. If you feel like your seborrheic dermatitis symptoms are affecting your quality of life and mood, talk to your doctor. They can review your treatment options and help connect you with a therapist or other health care provider who can help you feel better.

Living With Comorbidities and Complications

Having other health conditions can make seborrheic dermatitis harder to manage. You may experience many symptoms at the same time that influence one another. Be sure to tell your health care provider or dermatologist about your symptoms and any underlying health problems. Treating all the conditions together may help improve symptoms and your overall quality of life.

Talk With Others Who Understand

MySebDermTeam is the social network for people with seborrheic dermatitis and their loved ones. MySebDermTeam members come together to ask questions, give advice, and share their stories with others who understand.

Are you experiencing other health conditions along with your seborrheic dermatitis? Do you take any particular steps to prevent infections? Share your tips and experiences in a comment below or on your Activities page.