Seborrheic Dermatitis

What is Seborrheic Dermatitis?

Seborrheic dermatitis is a common inflammatory skin disease that causes scaly, red patches in areas rich in oil glands, particularly the scalp, face and body folds.^[1] It is chronic, relapses and remits, and affects about 4 percent of people worldwide, more often adults than children.^{[1, 2]}

Common symptoms

The typical symptoms are scaling, redness and itching.^[3] They occur most often on the scalp, face, chest, back, armpits and groin. Mild scalp flaking without much redness is known as dandruff.^{[3, 4]}

• Greasy, yellowish or white flakes on the scalp, eyebrows or beard
• Red or pink patches along the sides of the nose, behind the ears and on the chest
• Itching, which affects many patients^[5]
• On darker skin, patches may look lighter or darker than the surrounding skin, with little redness^[5]

Seborrheic dermatitis of the eyelid margins can occur with blepharitis, which has its own eye care.^[6]

Causes and risk factors

The exact cause is not certain. Three factors are generally agreed upon: oil secretion by the sebaceous glands, colonization by Malassezia yeast, and some form of immune dysregulation that makes a person prone to the condition.^[5] The skin changes are thought to be an inflammatory response to Malassezia yeast, a normal skin organism.^[3]

Other predisposing factors include a weakened immune system, such as in HIV infection, skin barrier problems, and endocrine and neurologic factors.^[7]

How it is diagnosed and treated conventionally

Seborrheic dermatitis is a clinical diagnosis based on where the patches are and how they look.^[3] A baby's form (cradle cap) is usually mild and clears by itself within the first year, and parents should ask their pediatrician about it.^[1]

Treatment aims to reduce Malassezia yeast and the inflammation it triggers. Antifungal agents such as ketoconazole are the mainstay for the face and body, and antifungal shampoos are used for the scalp. Topical corticosteroids and calcineurin inhibitors are used only for short periods because of possible side effects.^{[3, 5]} Because the condition relapses, long-term maintenance is often needed.^[4]

Why Seborrheic Dermatitis calls for a whole-person approach

Seborrheic dermatitis is not just a yeast problem. Researchers now think that skin oils, the skin barrier, skin microbes and the immune system all play a part, and that Malassezia may over-grow when the skin environment already favors it.^[7]

Care that addresses these background factors, along with stress and itch, is a reasonable addition to antifungal treatment, though research on that approach is still limited.

Sebum and the skin barrier

An intrinsic change in the amount or makeup of skin oil, or a weakened skin barrier, has been proposed as a basis of the condition, creating conditions in which Malassezia over-colonizes the skin.^[7]

Skin microbes

A systematic review of 12 studies found a changed balance of skin microbes in people with seborrheic dermatitis and dandruff, with more Malassezia restricta relative to Malassezia globosa, and Malassezia was linked to higher itch scores and disease severity.^[8]

Diet and lifestyle

A systematic review of 13 studies found that a Western diet was associated with a higher risk of seborrheic dermatitis in women, that eating more fruit was associated with lower risk, and that regular alcohol use was often associated with the condition. The authors said interventional studies are still needed.^[9]

Stress and itch

Stress and itch feed each other. A review found that stress can make itch worse, and that this involves the stress hormone axis and the sympathetic nervous system acting on skin mast cells and nerves.^[10] This review was about itch in general, not specifically seborrheic dermatitis. Stress management is therefore a sensible part of care for people whose flares follow stressful periods.

Acupuncture for Seborrheic Dermatitis

What the research shows

We found no clinical trials of acupuncture for seborrheic dermatitis. A PubMed search turned up only a trial protocol for acupuncture in seborrheic alopecia, a hair loss condition, and no results for the skin disease itself.

The research that exists concerns itch in other conditions. An updated systematic review of acupuncture in dermatology reported improved outcomes in uremic itch, atopic dermatitis, urticaria and itch, and concluded that larger sham-controlled trials are needed.^[11] Whether this applies to the itch of seborrheic dermatitis is not known.

How acupuncture may work

For seborrheic dermatitis there is no mechanism research. Acupuncture is sometimes used to ease stress, and stress can worsen itch in general, but this link has not been tested in this condition.^[10] These are possible explanations, not established facts.

What treatment involves

Treatment uses fine, sterile, single-use needles placed at points chosen for you, and usually left in place for about 20 to 40 minutes. A course of several visits is typical, with reassessment along the way. Needles are not placed into inflamed or infected patches of skin.

In prospective studies, about 9 in 100 patients had a minor reaction such as bleeding, soreness or redness at a needle site, and serious events occurred in about 1 in 10,000 patients.^[12] Tell the practitioner first if you have a bleeding disorder, take blood thinners, are pregnant, or have a pacemaker (relevant to electroacupuncture).

Ayurvedic medicine for Seborrheic Dermatitis

The Ayurvedic view

Ayurveda groups scalp scaling and flaking under conditions often called Darunaka, described as a disorder in which dryness, itching and flaking are linked to aggravated Vata and Kapha, sometimes with Pitta. In this traditional framework, irregular digestion and an oily, heavy diet are also thought to contribute. These are traditional categories used to choose treatment, not biomedical diagnoses.

Therapies that may be used

Care is chosen for the individual and traditionally combines:

• Diet and daily routine, such as regular meals, less heavy, greasy and sugary food, and steady sleep
• Gentle scalp oil applications chosen to suit the skin type, avoided when the scalp is inflamed or weeping
• Herbs such as neem and triphala, traditionally used for skin and digestion
• Transdermal medication therapy, meaning an herbal preparation applied to the skin, where appropriate

Panchakarma, a set of traditional cleansing procedures, is not appropriate during pregnancy, acute illness or frailty, and it is not a substitute for medical treatment of a skin condition.

What the research shows

The research is very limited. We found no clinical trials of Ayurvedic treatment for seborrheic dermatitis as a whole. One 8-week placebo-controlled trial of 80 people with scalp seborrhea, meaning an oily scalp, found that triphala taken by mouth lowered scalp oil levels and gave higher satisfaction than placebo. It did not measure scaling or redness, so it does not show benefit for the dermatitis itself.^[13] A systematic review of diet and seborrheic dermatitis mentioned the same trial and called for more studies.^[9]

Herbal medicine for Seborrheic Dermatitis

Herbs and formulas that have been studied

Herbal research in this area focuses on dandruff, the mildest form of seborrheic dermatitis. Essential oils and plant extracts such as tea tree oil, thyme, aloe vera and mint have been tested for their effect on the microbes linked to dandruff.^[14] A review of aloe vera in dermatology listed seborrheic dermatitis among the conditions where topical aloe vera might be effective.^[15] We did not find trials of Chinese herbal formulas for seborrheic dermatitis.

What the research shows

The evidence is limited. In a single-blind trial of 126 people aged 14 and older with mild to moderate dandruff, a 5 percent tea tree oil shampoo used daily for 4 weeks improved a dandruff severity score by 41 percent, compared with 11 percent for placebo, with better itch and greasiness scores and no adverse effects reported.^[16] This was one trial in dandruff and not in moderate or severe seborrheic dermatitis. A broader review of tea tree oil in dermatology noted that several studies suggest it may be useful for seborrheic dermatitis.^[17]

Reviews describe many plant products with anti-dandruff activity in the laboratory, but state that clinical research is needed before conclusions can be drawn about benefit in people.^[14] Aloe vera has not been explored sufficiently in well-designed trials.^[15]

Safety and herb-drug interactions

Herbs are active substances and can interact with medicines. Case reports describe bleeding when warfarin was combined with herbs including dang gui (Angelica sinensis), dan shen (Salvia miltiorrhiza), ginger, ginseng and Boswellia.^[18] A wider review found that herb-drug interactions can have serious consequences and recommended telling your doctor about herbs you use.^[19]

Herbal products applied to the skin, including essential oils, can cause irritation or allergy, so tell your dermatologist what you use on inflamed skin. In one study, about one fifth of Ayurvedic products bought online contained detectable lead, mercury or arsenic.^[20] Herbs should come from tested sources and be prescribed individually. Tell us if you are pregnant or breastfeeding, have liver or kidney disease, or take medicines that affect the immune system.

Translating traditional medicine into modern biological language

The links drawn here are interpretation, not equivalence. Chinese medicine often describes greasy, itchy, scaly skin as dampness and heat, sometimes with dryness or wind from blood deficiency. Researchers studying seborrheic dermatitis measure things that loosely parallel this picture: sebum production, Malassezia overgrowth and the immune response to it.^{[5, 7]}

Ayurveda's description of excess oil and heaviness in Kapha, and of impaired digestion, may loosely echo research on skin oils and on diet and nutrition in this condition.^[9] No study has shown that a dosha or a pattern corresponds to a specific biological process.

How this care fits with your medical care

Integrative care for seborrheic dermatitis is complementary. Keep your physician or dermatologist and your prescribed antifungal or anti-inflammatory treatments, and do not stop or change them without your prescriber. We do not diagnose skin conditions, and similar-looking rashes such as psoriasis, eczema or fungal infections need a clinician's assessment.

Please bring your diagnosis, a list of the shampoos, creams and medicines you use, any supplements or herbal products, and notes on what seems to trigger flares.

When to seek urgent medical care

Most seborrheic dermatitis is not dangerous, but some changes need prompt attention.

• Skin that becomes very red, hot, painful, swollen or oozing, or has crusts or pus, which may be infected
• A rash with fever or feeling very unwell
• Eye pain, redness or vision changes with eyelid inflammation
• A widespread, sudden or severe rash, especially in someone with a weakened immune system
• A rash that does not respond to treatment, or a patch that grows, bleeds or does not heal

If you have swelling of the face or throat, trouble breathing or a rapidly spreading rash with high fever, call 911 or go to the nearest emergency department.