Seborrheic Dermatitis - the Most Common Scalp Condition

What Is Seborrheic Dermatitis?

Seborrheic dermatitis is a papulosquamous disorder with an inflammatory component. It is characterized by well-defined erythema and accompanied by overlying greasy scales. Seborrheic dermatitis will be seen over areas rich in sebum, namely scalp, eyebrows, the center of the face, eyelids, around and in the ear canal, upper chest, back, and flexural areas of the body. In addition to sebum, this condition is linked to Malassezia, immunological abnormalities, and activation of complement factors.

What Causes Seborrheic Dermatitis?

Despite how the lesion looks, it is not caused by compromised hygiene or allergy. The cause is complex and unclear. A combination of factors is believed to cause seborrheic dermatitis, such as;

1. Stress.

2. Overall health condition of the individual.

3. Climate (cold and dry).

4. Yeast that resides on our skin as commensals.

5. Genetics.

6. Medications like Psoralen, Interferon, and Lithium.

Malassezia, the yeast that normally resides on the human skin's surface, exceeds in number. The human body's immune system overreacts to overgrowth or excess of Malassezia with an inflammatory response that results in skin changes.

What Are the Characteristic Features of Seborrheic Dermatitis?

Seborrheic dermatitis has active and inactive phases. Intermittent active phases manifesting with burning sensation, greasy, moist flakes, and itching with reddish skin beneath the patches. It is alternative with inactive periods; activity is increased in winter and early spring, with remissions commonly occurring in summer. It has a biphasic presentation in early infancy (within the first three months of life) and later in adult life (usually after the third decade).

During the active phase, the chance of secondary infection is mainly in intertriginous areas, eyelids, and postauricular areas. Candida overgrowth is common in infantile napkin dermatitis.

How Does Seborrheic Dermatitis Manifest?

The clinical presentation of seborrheic dermatitis varies with age.

Cradle Cap - When an infant suffers from seborrheic dermatitis, it tends to form a layer on the scalp and is known as a cradle cap. Clinical presentation of the cradle cap includes a yellow, greasy scale on the scalp and a thick layer of scale covering the entire scalp. The scale is often yellow to brown in color, and with time, the scale becomes flaky and easily gets detached. In infants, this disease can also involve the face, usually the baby's eyelids, around the nose or ears, and it can also involve the napkin area. It usually subsides within six months to 1 year of age.

In Adults and Adolescents - The condition causes scaly patches on the skin, with the skin beneath the patches red. These scales often are moist and greasy. These scales can flake off and range from yellowish to white. They can also result in itching and burning sensations.

Who Is More Susceptible to Seborrheic Dermatitis?

Though the condition can affect anyone regardless of race, sex, and age, the incidence is high in the following age groups;

• Infants aged three months and below.

• Adults between 30 to 60 years of age.

What Medical Conditions Increase the Risk of Seborrheic Dermatitis?

The incidence of seborrheic dermatitis is more common in medical conditions like,

• HIV (human immunodeficiency virus) infections.

• Parkinson's disease.

• Epilepsy.

• Alcoholism.

• Depression.

• Acne.

• Psoriasis.

• Recovery from stroke or heart diseases.

How Is Seborrheic Dermatitis Diagnosed?

Diagnosis is usually made with the history of waxing and waning severity and by the distribution on examination. A skin biopsy is needed in patients with more than 90 % body surface area involvement.

How Is Seborrheic Dermatitis Treated?

Infant's Cradle Cap:

Many babies develop this type of rash on their scalp, and this condition typically decreases by 6 to 12 months of age. Till that time, to reduce the rashes, the following things can help.

1. Daily shampooing with baby shampoo will help in softening the flakes or scales. Once the scale starts softening, gentle brushing will remove the scales.

2. Rashes on the infants' napkin area involvement or in other body areas can look like psoriasis or eczema or an allergic reaction, each of them requiring a different treatment plan.

Scalp Involvement in Adults:

One should use an anti-dandruff shampoo twice weekly. If you are using one dandruff shampoo and not getting relief, then try alternating dandruff shampoo. Use the second dandruff shampoo for two days in a row.

The active ingredients of dandruff shampoos are Zinc pyrithione, Selenium sulfide, Coal tar, Ketoconazole, Corticosteroids, Ciclopirox olamine, Salicylic acid, and Sulfur.

When using anti-dandruff shampoo, follow the instructions on the shampoo bottle. Some require that you lather and leave it on for about five minutes before rinsing, and others need you to wash it soon after application. It is always wise to consult a dermatologist for a product recommendation. If the shampoo that you are using has coal tar, then protect your scalp from the sun. One can do this by wearing a hat outdoors and not using indoor tanning devices, such as tanning beds and sun lamps.

Skin Involvement:

• Wash the skin frequently with 2 % Zinc pyrithione containing soap. Scales should soften by wetting the skin thoroughly before washing and applying good-quality moisturizer after bathing.

• Apply a tar-containing cream and leave it for several hours before rinsing.

• Apply cream which contains Sulfur and Salicylic acid. Do not use any kind of occlusive cream like petroleum jelly to soften the scales as it may worsen the condition.

What Are Some General Tips to Prevent Such Skin Conditions?

1. Cleanse, tone, and moisturize your skin. Following a skincare routine is necessary for good skin health. Use sun protection (sunscreens) while indoors and outdoors and regardless of the climate (whether cloudy or winters, etc.).

2. Managing stress is equally important for skin health. Balance your stress levels.

3. Get an adequate amount of sleep daily (eight hours).

4. Drink upto three liters of water every day.

Seborrheic dermatitis is believed to be triggered by factors such as stress, hormonal imbalances, the use of skincare products containing chemicals, harsh detergents, etc. Be gentle with your skin, stay stress-free, and prevent such skin conditions. Have more doubts? Our skin experts are always at your help.