Seborrheic Dermatitis: A Dermatologist Talks Treatment

What is seborrheic dermatitis?

Seborrheic dermatitis is a common skin condition that affects the areas of the body that have a high density of oil-producing (sebaceous) glands.

It affects 1 to 5 percent of the general population, and often has a chronic, relapsing course.

The exact cause of seborrheic dermatitis is not completely clear, although genetic and hormonal influences have been shown to play a role in this condition. Furthermore, certain fungal microorganisms that live naturally on the skin, belonging to the genus Malassezia, can also contribute to seborrheic dermatitis.

Patients of any age can develop seborrheic dermatitis, including infants (in which it is known as “cradle cap”), teenagers, and adults.

Flares of seborrheic dermatitis have been associated with many factors, such as stress, hormonal changes, or illness. Skin irritants such as certain detergents, solvents, chemicals, and soaps may also worsen seborrheic dermatitis. In general, seborrheic dermatitis is slightly more common in men than in women. Patients with certain diseases that affect the immune system (such as HIV/AIDS) and the nervous system, such as Parkinson’s disease, are also at increased risk of developing seborrheic dermatitis.

Seborrheic dermatitis mainly affects the scalp, where it may range from dry flakes (dandruff) to yellow, greasy scales with reddened underlying skin. Patients can also develop seborrheic dermatitis on other oily areas of their body, such as the face, upper chest and back. Seborrheic dermatitis is not harmful to a patient’s health, nor is it contagious, and fortunately complications are rare. It can, however, have a profound impact on a patient’s quality of life and emotional well-being.

How can you identify it?

Example of seborrheic dermatitis on the face. Photo courtesy of Skinsight.com, Logical Images, Inc.

Seborrheic dermatitis can often resemble other skin conditions. The typical symptoms that patients with seborrheic dermatitis experience include redness, flaking, scaly patches, and sometimes itching of the affected skin. Like eczema and psoriasis, two other common skin diseases, seborrheic dermatitis produces inflammation of the skin.

Seborrheic dermatitis can look like and/or overlap with other skin conditions. If you are experiencing symptoms, it is important to see a dermatologist to get the correct diagnosis and treatment. There is no specific test for diagnosing seborrheic dermatitis. Your dermatologist will ask about your medical history and also perform a physical examination of your skin. Usually, these measures alone will be sufficient to make the diagnosis.

In certain cases, a scraping of skin under a drop of potassium hydroxide is examined under a microscope to exclude a fungal infection. Similarly, a skin biopsy (a procedure in which a small sample of skin is removed) may be required in rare cases to confirm the diagnosis or rule out other conditions that mimic seborrheic dermatitis.

How is seborrheic dermatitis different from atopic dermatitis?

Example of seborrheic dermatitis on the chest. Photo courtesy of Skinsight.com, Logical Images, Inc.

Atopic dermatitis and seborrheic dermatitis are both forms of eczema, a general term that describes inflammatory skin conditions that produce significant redness and itching.  Not uncommonly, a single person can be diagnosed with both seborrheic dermatitis and atopic dermatitis. Atopic dermatitis nearly always produces itchy, red skin but seborrheic dermatitis is not always itchy. The areas of affected skin can also differ between both of these conditions. Distinct from seborrheic dermatitis, atopic dermatitis most often affects the face, hands, feet, inside of the elbows and behind the knees.

Additionally, Malassezia organisms are known to contribute to seborrheic dermatitis. As a result, the treatment approaches to atopic dermatitis and seborrheic dermatitis are different.

Topical medications such as steroids, pimecrolimus, and tacrolimus are traditionally used to help relieve symptoms of atopic dermatitis. But for seborrheic dermatitis, the treatments instead target fungi that like oil glands, like Malassezia.

Nonetheless, distinguishing between seborrheic dermatitis and atopic dermatitis can pose a challenge even for healthcare professionals, and it is therefore important to see a physician should you develop concerns about your skin.

How is seborrheic dermatitis treated?

The symptoms of seborrheic dermatitis can be effectively controlled, and currently a variety of medicated treatments are available both over the counter and by prescription. A combination of self-care measures and drug therapy is often required to optimally treat seborrheic dermatitis.

For adults, long-term maintenance may be necessary to control the symptoms of seborrheic dermatitis. Dandruff, which represents mild seborrheic dermatitis of the scalp, may be treated with over-the-counter anti-dandruff shampoos. These contain one of several available active ingredients: selenium sulfide, tar, zinc pyrithione, and ketoconazole. These have all been shown to be equally effective after four weeks of consistent use.

Antifungal solutions containing ketoconazole, such as the shampoo Nizoral, are considered mainstays of treatment because they kill fungi such as Malassezia. For best results, shampoos should be left in place for five to ten minutes before rinsing, and then rinsed out completely. Initially, medicated shampoos may be used every day, and then as symptoms improve, they can be tapered to every other day. If one shampoo does not improve symptoms after four to six weeks, then a different shampoo may be tried.

For seborrheic dermatitis affecting areas other than the scalp, topical steroids such as hydrocortisone can also alleviate the redness and itching. These may be applied once or twice daily for up to two weeks. Very rarely, a systemic medication (often in the form of a pill), such as an antifungal medication or steroid, may be required to control symptoms if they are severe.

Fortunately, although there is no permanent cure yet, seborrheic dermatitis often improves with an excellent response once treatment is started.

Ultimately, however, it is important to note that if symptoms fail to improve with therapy or worsen, then you should make an appointment with a health care provider to have your symptoms evaluated further.

Conclusion

In conclusion, seborrheic dermatitis is a condition that can be readily managed with a balance of self-care and medicated treatments. Patients experience improvement and flares intermittently throughout their disease course, which tends to be chronic.

Factors such as hormones, genes, exposures to chemicals, and stress can all potentially trigger flares of seborrheic dermatitis.

For overall health, it is also important to consult with your physician should you notice any changes in your skin, such as symptoms suggestive of seborrheic dermatitis.

Monica Enamandram, M.D. is a resident physician at Memorial Sloan-Kettering Cancer Center. She earned her MD degree at Harvard Medical School, and will continue her residency training in Dermatology at Stanford University Hospitals. She is interested in patient education and clinical research in dermatology, and is excited to develop successful preventive measures and treatment regimens for eczema.