Seborrheic Dermatitis – Symptoms, Causes & Treatment

Seborrheic dermatitis is a common skin disorder characterised by development of scaly patches on the skin that shed off easily. Dandruff is considered as the milder variant of seborrheic dermatitis that causes flaking and scaling of the scalp skin. Seborrheic dermatitis is a common skin problem and affects nearly 12% of general population. In adults the peak incidence of seborrheic dermatitis is seen at 30 to 60 years of age. In adolescents seborrheic dermatitis usually occurs in its milder form as dandruff. Seborrheic dermatitis can also occur in infants and it is known as Cradle cap that causes crusty yellow scaly patches on the scalp. This article gives detailed information on the causes, risk factors and treatment options available to treat this skin disorder.

What is Seborrheic Dermatitis?

Seborrheic dermatitis is a chronic inflammation of skin that causes scaly and itchy patches on the skin. The flaking of skin is thought to occur due to the inflammation of skin in the sebum rich areas such as scalp, face, upper chest, and back. The skin flakes can be yellow or red in colour and may appear oily or dry. The skin lesions in seborrheic dermatitis generally appear symmetrical in pattern. Although visually unpleasing the seborrheic dermatitis is neither contagious nor fatal.

Causes of Seborrheic Dermatitis

Although seborrheic dermatitis is one of the most common and chronic skin disorders its etiology is not clearly understood. Inflammation is considered to be the most common cause of seborrheic dermatitis. Some experts also suggest that a fungus called Malassezia which is present in the normal bacterial flora of the skin can result in seborrheic dermatitis. In addition poor immunity, mental stress, medical condition such as Parkinson’s disease, or administration of some medicines can also cause seborrheic dermatitis. Some more causes are listed below.

List of Common Causes of Seborrheic Dermatitis Include

Inflammation of skin
Fungal infection with Malassezia
High stress
Poor immune system
Medical condition such as Parkinson’s disease or HIV infections
Treatment with psychotropic drugs such as haloperidol , lithium, buspirone, and chlorpromazine
Hormonal imbalance
Nutritional deficiencies

Symptoms and Signs of Seborrheic Dermatitis

In adolescents seborrheic dermatitis begins with mild greasy scaling of the scalp with erythema. In infants, seborrheic dermatitis may present as thick, greasy scales on the vertex of the scalp. In adults, the condition presents as uneven scaling and lesion in the sebum rich areas such as scalp, eyebrows, forehead, nasal creases, ears, and central chest. However, scalp and face is affected the most. Seborrheic dermatitis on scalp also causes severe itching due to flaking of skin. The scaling of scalp associated with seborrheic dermatitis is often bothersome as the dry flakes easily fall off and are often visibly apparent on darker clothing.

List of Common Signs and Symptoms of Seborrheic Dermatitis

In adults

Red patches on skin
Uneven skin lesions
Scaling of skin
Greasy appearance of skin
Dry flakes that shed off easily
Burning or itching of skin

In infants

Thick greasy scales on the vertex of scalp
White, off-white, or yellow skin flakes on the scalp

Treatment of Seborrheic Dermatitis

In most cases seborrheic dermatitis clears up on its own. However it can show intermittent periods of relapse and so experts have identified some treatment options for seborrheic dermatitis. To begin with, a good skin care regimen is the most important part of seborrheic dermatitis treatment. The main objectives of treatment include reduction of skin inflammation, treatment of fungal infection, reduction of itching, and reduction in scaling of skin. The commonly prescribed treatments for seborrheic dermatitis include,

Antifungal medications: Antifungal medications are used to clear the infection caused by Malassezia. Antifungals can be used as shampoos in case of seborrheic dermatitis of scalp or as topical skin lotions for other parts of the body.
Topical creams or lotions containing Corticosteroids: Cotricosteroids are used to reduce the inflammation of skin. These are mainly recommended in seborrheic dermatitis associated with other diseases such as HIV infection where the cause is not microbial infection.
Anti-inflammatory medications: These can be used as shampoo, applied to the scalp, or topical solutions, creams or gels applied to other affected body parts.
Keratolytics: Keratolytics such as coal tar, salicylic acid and zinc pyrithione shampoos are widely used to treat seborrheic dermatitis of scalp.
Light therapy: Phototherapy that includes exposure to sunlight or UV light is proposed as a treatment to seborrheic dermatitis as it is believed to reduce the growth of fungus.
Herbal Therapy: Herbal remedy containing Tea tree oil (Melaleuca oil) is effective and well tolerated when used daily as a shampoo. It is used commonly as a natural alternative for treating scalp seborrheic dermatitis

Risk Factors of Seborrheic Dermatitis

Although Seborrheic dermatitis can affect people of any age, few factors make some people more vulnerable to developing the condition. The risk factors that can aggravate seborrheic dermatitis include,

Being in specific age group: Studies reveal that incidence of seborrheic dermatitis peaks during three age periods – in the first three months of life, during puberty but mainly in milder form, and in adulthood at 40 to 60 years of age.
Male gender: Experts report that men are more likely to be affected than women in all age groups. Although some women may also develop seborrheic dermatitis, the frequency of occurrence or relapse is more common in men. This suggests that seborrheic dermatitis may be associated with sex hormones such as androgens.
Exposure to weather changes: Seborrheic dermatitis shows a seasonal pattern. It is reported to be severe during winter, and improve usually during summer.
Low Immune power: Seborrheic dermatitis shows a higher prevalence in people with compromised immunity such as HIV/AIDS patients, organ transplant recipients, and cancer patients.
Some other lifestyle factors such as poor hygiene, emotional stress, nutritional deficiencies, and sleep deprivation can also increase the risk of seborrheic dermatitis.

What Does Seborrheic Dermatitis Look Like?

Seborrheic dermatitis is characterized by itchy skin patches that have easily detachable greasy scales. Seborrheic dermatitis looks different at different body parts. It may also appear different in infants, adolescents and in adults as given below.

Seborrheic Dermatitis in Infants

On the scalp: White to yellow plaques that are coated with thick and greasy scales on vertex of scalp
Other body parts: Appears especially in the body folds as moist, shiny, non-scaly lesions

Seborrheic Dermatitis (dandruff) in Adolescents

On the scalp: Appears as white dry skin flakes that fall off easily

Seborrheic Dermatitis in Adults

On the scalp: Greasy scales, uneven skin flakes that detach easily. The skin lesions may also reach into forehead as scaly erythematous border.
On the face: Itchy scales with greasy appearance
On the chest: Small, reddish-brown follicular papules with greasy scales that eventually spread into larger patches resembling shape of flower petal.

How is Seborrheic Dermatitis Diagnosed?

A skin specialist or a trichologist can do the diagnosis of seborrheic dermatitis by,

Reviewing medical history
Examining the skin an rash

Some other skin conditions such as psoriasis, contact dermatitis, and erythrasma may be confused with seborrheic dermatitis. Therefore, during diagnosis the skin specialist checks the skin rash closely for appearance of lesion, its colour, location and pattern. Seborrheic dermatitis does not cause hair loss and does not affect organ systems other than the skin. If the conclusion cannot be made on the basis of clinical presentation and skin examination, the skin lesions or scales are scraped off and sent for further examination known as biopsy. The laboratory studies help in differential diagnosis and can confirm seborrheic dermatitis.

What is the Prognosis of Seborrheic Dermatitis?

Seborrheic dermatitis is not a serious or life-threatening problem. In most cases it cures on its own. However, it may also recur or relapse and present as a long term skin condition. However, the response to available treatment options for seborrheic dermatitis is generally very good. Thus prognosis of seborrheic dermatitis is considered to be optimistic and positive.

Is there a Way to Prevent Seborrheic Dermatitis?

Good skin hygiene is the most essential way to prevent seborrheic dermatitis or any other skin disorder. Apart from this managing stress, avoiding exposure to extreme weather changes, regular use of moisturizers to keep the skin hydrated, and nutrient rich diet can help to prevent seborrheic dermatitis. Relapse of seborrheic dermatitis can be prevented through regular treatment with antifungal shampoos, corticosteroid lotion and other available treatment modalities.

What are Complications of Seborrheic Dermatitis?

Although seborrheic dermatitis is not a fatal condition, it can lead to severe mental stress and discomfort due to itching of scalp and constant flaking of the skin. The diagnosis of seborrheic dermatitis can get challenging as it is often misdiagnosed into other conditions such as psoriasis, atopic and contact dermatitis, and erythrasma. In addition, some of the common treatment modalities may add to the complications due to their side effects. For instance, antifungal agents may result in burning or itching sensation to the skin, topical corticosteroids may cause skin atrophy, whereas use of tar is associated with development of contact dermatitis.