Seborrhoeic dermatitis

Seborrhoeic dermatitis
Classification and external resources
ICD-10	L21.
ICD-9	690
DiseasesDB	11911
MedlinePlus	000963
eMedicine	derm/396
MeSH	D012628

Seborrhoeic dermatitis (also Seborrheic dermatitis AmE, seborrhea) (also known as "Seborrheic eczema"^[1]) is an inflammatory^[2] skin disorder affecting the scalp, face, and trunk causing scaly, flaky, itchy, red skin. It particularly affects the sebum-gland rich areas of skin.

Causes

The cause of seborrhoeic dermatitis remains unknown,^[3] although many factors have been implicated.

Acute form of seborrhoeic dermatitis on scalp

Stress

Seborrhoeic dermatitis may be aggravated by illness, psychological stress, fatigue, change of season and reduced general health.

In adolescents and adults, seborrhoeic dermatitis usually presents as scalp scaling (dandruff) or as mild to marked erythema of the nasolabial fold during times of stress or sleep deprivation.^[4]

Nutritional hypo- and hyperalimentation

In children, excessive vitamin A intake can cause seborrhoeic dermatitis.^[5]

Lack of biotin,^[4] pyridoxine (vitamin B6)^[4][6] and riboflavin (vitamin B₂)^[4] may also be a cause.

Fungal

Another example of seborrhoeic dermatitis on scalp

Alternatively, seborrhoeic dermatitis is believed to be an inflammatory reaction related to a proliferation of a normal skin inhabitant, a yeast called Malassezia (formerly known as Pityrosporum ovale). The main species found in the scalp is Malassezia globosa. It produces toxic substances that irritate the skin. Patients with seborrhoeic dermatitis appear to have a reduced resistance to the yeast.

Malassezia growth is supported by saturated, not unsaturated fatty acids. In all cases, pure, unsaturated FAs were unable to support growth of M. globosa or M. furfur. Interestingly, growth of both species was supported by saturated FAs. This is further evidenced by lard, which is rich in saturated triglycerides. Implications for dandruff and seborrheic sermatitis: Previously, it has been shown that: 1. While number density of M. globosa and M. restricta do not directly correlate to dandruff presence or severity, removal correlates directly with amelioration of flaking. 2. In dandruff susceptible individuals pure OA, an unsaturated FA and Malassezia metabolite, induces flaking in the absence of Malassezia by direct effects on the host skin barrier. This finding, that Malassezia require saturated, and not unsaturated FAs, coupled with previous data, supports the following hypothesis:

Malassezia hydrolyze human sebum, releasing a mixture of saturated and unsaturated fatty acids. They take up the required saturated FAs, leaving behind unsaturated FAs. The unsaturated FAs penetrate the stratum corneum and due to their non-uniform structure breach the skin's barrier function. This barrier breach induces an irritation response, leading to dandruff and seborrheic dermatitis.^[7]

The widely present yeast, Malassezia furfur (formerly known as Pityrosporum ovale), is involved,^[8][9] as well as genetic, environmental, hormonal, and immune-system factors.^[10][11] The claim that seborrhoeic dermatitis is an inflammatory response to the yeast has not been proven.^[12] Those afflicted with seborrhoeic dermatitis have an unfavourable epidermic response to the infection, with the skin becoming inflamed and flaking.

Secondary to other medical conditions

The condition is one of the autonomic signs of Parkinson's disease.

Those with immunodeficiency (especially infection with HIV) and with neurological disorders such as Parkinson's disease and stroke are particularly prone to it.^[13]

Symptoms

Another example of seborrhoeic dermatitis on scalp

The condition's symptoms appear gradually and usually the first signs of seborrheic dermatitis are the flakes of skin called dandruff.^[14] The symptoms may occur anywhere on the skin of the face, behind the ears and in areas where the skin folds. These are common sites that become red and flaky. The flakes can be yellow, white or grayish.^[15] In more rare cases, redness and flaking may occur on the skin near the eyelashes, on the forehead or around the sides of the nose. Other body areas where these symptoms occur are the chest and upper back. The symptoms of seborrheic dermatitis can appear basically on any part of the body where there is certain amount of hair and therefore follicles which might became inflamed. A sign that the condition has become more severe is the formation of thick, oily and yellow scales which might appear on the forehead, around the sides of the nose or on the skin near the eyelashes.

In more severe cases, yellowish to reddish scaly pimples appear along the hairline, behind the ears, in the ear canal, on the eyebrows, on the bridge of the nose, around the nose, on the chest, and on the upper back.^[16]

Commonly, patients experience mild redness, skin lesions and in some cases hair loss.^[17] Other symptoms include patchy scaling or thick crusts on the scalp, red, greasy skin covered with flaky white or yellow scales, itching, soreness and yellow or white scales that may attach to the hair shaft.^[18]

Seborrheic dermatitis can occur in infants younger than three months and it causes a thick, oily, yellowish crust around the hairline and on the scalp. Itching is not common among infants. Frequently, a stubborn diaper rash accompanies the scalp rash.^[19] Usually, when it occurs in infants the condition resolves itself within days and with no treatment.

Many patients experience alternating periods of the symptoms, when they either improve or suddenly worsen. In adults, symptoms of seborrheic dermatitis may last from few weeks to even years.

The condition is referred to a specialist when it becomes painful, the individual suspects that the skin might have become infected or they have tried self-care therapy without success. Also, seborrheic dermatitis can cause discomfort and interfere in one's daily activities. Addressing the condition to a doctor is important in order to prevent potentially long-lasting damage to the hair follicles which may lead to hair loss.

Hair loss

Side effects to inflammation may include temporary hair loss. If severe outbreaks are untreated for extended intervals, permanent hair loss may result, because of damage to hair follicles.

It is still unclear if seborrheic dermatitis causes permanent hair loss, although the inflammation involves the hair follicles.^[20] Some researchers claim that the yeast causing seborrheic dermatitis is the main cause of hair loss due to this condition. For others, hair loss can be a result of the many other factors combined: excess oil production by the oil glands due to reasons such as hormonal imbalance, stress, extreme hot or cold weather conditions, weakened immune system, Parkinson's disease, certain neurological conditions and keeping the scalp unclean.

Treatments

Dermatologist recommend topical treatments such as shampoos, cleansers or creams/lotions that contain antifungal, anti-inflammatory, sebo-suppressive or keratolytic ingredients:

One approach is to try different combinations of the usual agents: a dandruff shampoo, an antifungal agent and a topical steroid. If this fails, short-term use of a more potent topical steroid in a "pulse fashion" may put some refractory patients into remission and actually decrease the total steroid exposure. Therapeutic choices for pulse therapy may include a nonfluorinated class III steroid such as mometasone furoate (Elocon) or an extra-potent class I or class II topical steroid such as clobetasol propionate (Temovate) or fluocinonide (Lidex). The class III topical steroid should be tried first, but if the condition remains unresponsive, the clinician may then choose to use a class I agent. These more potent agents may be applied once or twice per day, even on the face, but must be stopped after two weeks because of the increased frequency of side effects. If the patient responds before the two-week limit, the agent should be stopped immediately. Adjuvant therapy including use of a dandruff shampoo, an antifungal agent, or both, is essential during the "pulse" period and should be continued as maintenance therapy after each pulse.

Treating seborrheic dermatitis is quite difficult to achieve given that there seem to be more than just one factor contributing to its development, but the condition can be held under control with few measures. Controlling the disorder can be done by using various medicated shampoos or creams. Maintaining the scalp clean is mandatory for sufferers of seborrheic dermatitis and therefore using anti-dandruff shampoos which are effective may be one way of preventing getting this condition. Also, there are several special shampoos that contain sulfur, zinc or salicylic acid. A thorough cleaning of the scalp is the first step to be made in preventing and curing this condition because by having a proper scalp hygiene, the bacteria and fungus are removed and the likelihood of developing a follicular inflammation is reduced.

Some creams may also be used to treat hair loss due to seborrheic dermatitis. Topical cortisone creams are highly effective in minimizing the symptoms of this condition, especially inflammation and itchiness. These creams are only available on prescription. On the other hand, it is believed that garlic ingestion can help in minimizing the fungal infection on the scalp. Moreover, a change in the diet should be considered given that foods rich in antioxidants and beta-carotene are efficient in reducing the inflammation.

Antifungal

OTC: Over the counter

• zinc pyrithione
• salicylic acid
• selenium sulfide
• ketoconazole 1%
• climbazole
• Piroctone olamine
• Clotrimazole

Prescription

• ciclopiroxolamine
• sodium sulfacetamide
• terbinafine^[21]
• Fluconazole
• Ketoconazole
• Itraconazole^[22]

Medications other than antifungals

• Coal tar (can be very effective, but banned in Europe, since coal tar is carcinogenic)
• Lithium gluconate^[23]
• Lithium succinate^[24]

• Vitamin B6 ointment^[25]
• Topical steroid: Chronic treatment with topical corticosteroids may lead to permanent atrophy and telangiectasia of the skin.^[26][27]
• Pimecrolimus, brand name Elidel^[28]

• Isotretinoin (Accutane) at low dose 5 mg to 10 mg: As a last resort in refractory disease, sebosuppressive agent isotretinoin (Accutane) may be used to reduce sebaceous gland activity. However, isotretinoin has potentially serious side effects and few patients with seborrhea are appropriate candidates for therapy.

Phototherapy

Dermatologists recommend the use of photodynamic therapy also known as phototherapy which uses UV-A and UV-B laser or red and blue LED light to inhibit the growth of Malassezia and reduce the inflammation.^[29][30][31]

Natural treatments

• Aloe Vera applied topically ^[32][33]
• Tea tree oil: diluted to 5% applied topically ^[34][35]
• Viola tricolor or Heartsease: applied topically. Is recognised by Germany's Commission E as Monograph 195 for the treatment of Cradle Cap a form of seborrheic dermatitis.^[36][37][38]
• Honey apply diluted crude(raw)honey (90% honey diluted in warm water) every other day on the lesions with gentle rubbing for 2-3 mins. Honey is left on for 3 hr before gentle rinsing with warm water. Treatment is continued for 4 weeks.^[39]
• Avocado Extracts: AV119^[40] & 5-alpha Avocuta, also known as butyl avocadate^[41] applied topically.
• Monarda fistulosa^[42]

Supplements

• Probiotics Lactobacillus casei^[43] and Lactobacillus paracasei^[44]
• Lactoferrin ^[45]
• Vitamin B₇ Biotin
• Vitamin B₆
• Vitamin B₂
• Vitamin B₃: Nicotinamide, also known as Niacinamide
• Zinc ^{[46][47][48][49][50][51]}

Diet

There is evidence that there is relationship between seborrheic dermatitis and intestinal yeast, such as candida.^[52] An antifungal diet consisting of the elimination of sugar should reduce seborrheic dermatitis.^[53][54]

Alternative treatments

Applying milk of magnesia may help clear up seborrheic dermatitis; one may apply on the face while showering and rinse off at the end of the shower.^[55]

See also

• Cradle cap
• Dandruff
• List of cutaneous conditions

References

External links