Seborrheic dermatitis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at June 19, 2016
StartDiseasesSeborrheic dermatitis

Seborrheic dermatitis is also known as dandruff. Many different medications may relieve this disorder though it is chronic. The rash affects one to five percent of adults, and it more commonly affects men than women. It is the most common skin complaint aside from acne.

Contents

Definition & Facts

Seborrheic dermatitis is an inflammatory skin disorder that often occurs in healthy individuals. The condition is not contagious. Seborrhea has a gradual onset with common symptoms including red, itchy, burning scalp.

Seborrhea is the result of abnormal skin cell growth, though the exact causes are unknown and may be a complex combination of factors. Seborrheic dermatitis in babies is known as cradle cap. Although most don't experience significant discomfort from the condition, seborrhea frequently becomes a mild, lifelong condition.

Symptoms & Complaints

Itching and crusty scales on the scalp are the most common complaint for seborrheic dermatitis. Scaling and a thick crust may form on the scalp lesions, and the hair may be filled with dandruff scales. The scales can be yellowish in color with an oily, moist consistency. Scratching may produce thick, crusty patches that ooze.

Seborrheic dermatitis can affect any oily, hair-bearing area of the body, but is usually confined to the head, face, and trunk. Although the disorder often originates on the scalp, rashes can spread to the armpits, under the breasts and groin folds. Flaky skin in the folds around the nose and behind the ears is common. Red inflamed skin may be found on the eyelids and in the eyebrows as well, sometimes advancing to the back and chest.

Rarely, the face may acquire inflamed hair follicles, as well. Advanced manifestations include oval, discoid plaques of raised skin. Black skin may experience some loss of pigment. Depression, frustration, and social anxiety frequently accompany a skin disorder such as dandruff. Low self-esteem and anger is sometimes a complaint of those dealing with a visible skin disorder. 

Causes

The cause of seborrheic dandruff is not well-understood, although oily skin seems to be a strong contributing factor. Many patients with seborrheic dermatitis are found to have an overgrowth of skin yeast (Malassezia) where the lesions are located. It is unknown as to whether this is the cause of the dermatitis, or a secondary factor. Antifungal medications are somewhat effective during flare-ups, so some conclude a fungal condition prompts the disorder. 

Although no particular cause of seborrheic dermatitis has been pinpointed, certain risks are associated with it. Seborrheic dermatitis may be linked to genetics, as it appears that family members may be similarly affected. Change of seasons may cause a recurrence, and flare-ups are more frequent in winter.

Symptoms may begin or be aggravated by psychological stress, illness, or fatigue. A skin condition that develops as a reaction to a negative emotional state is called a psychodermatological disorder. Symptoms become a vicious cycle, as secondary psychiatric reactions may become part of a person's response to the social frustrations of the disease. 

Certain immune dysfunctions like human immunodeficiency virus (HIV) may cause seborrheic dermatitis. Around 35 percent of those with HIV exhibit seborrheic conditions, and 85 percent of those diagnosed with acquired immune deficiency exhibit symptoms. Seborrheic dermatitis also affects those with Parkinson's disease and other neurological disorders more often than others. Seborrheic dermatitis can often be an important diagnostic sign because it can be a presenting signal of systemic diseases like diabetes 2, thyroid disease, and pernicious anemia.

While rare in developed countries, malnutrition can contribute to seborrheic dermatitis. In developed countries, malnutrition is most often the result of illness, restrictive diets, or alcoholism, and skin diseases can be aggravated by nutritional deficiencies associated with these conditions. Protein, niacin, essential fatty acid, and zinc shortages are often found in dermatitis conditions like seborrhea.

Diagnosis & Tests

There is no specific test to determine seborrheic dermatitis. Instead, diagnosis depends upon a physical examination of the specific symptoms of the dermatitis, and a patient's history of the disorder and related skin conditions. If a physician is unsure of the diagnosis, a biopsy may be taken. Epidermal perakeratosis will be noted, which indicates the high cell turnover characteristic of skin rash diseases.

Treatment & Therapy

Seborrheic dermatitis is difficult to treat because there is often no lasting resolution of the rash despite the multitude of treatment options available. A dermatologist will be recommended to determine whether the rash presents as seborrheic or another skin disorder. Once that is clinically determined, a plan of medical options to control the rash can be put into place. It is best to begin with readily available antifungal agents, such as ketoconazole. The shampoo version of this antifungal is available through prescription and in over- the-counter products like Nizoral®

Inflammation associated with the condition can be addressed with creams or lotions containing corticosteroids. These are available over-the-counter and through prescription. Use of prescription corticosteroids presents risk of thinning of the skin over time. Side effects of the medication may include burning and irritation as well. It is recommended that prescription-strength corticosteroids be alternated with over-the-counter products of lesser strength for long-term treatment.

Immunomodulators are medications that suppress an overactive immune system. The topical versions can be used for short-term use to modify the amount of oil (sebum) produced by sebaceous glands. If the condition is very resistant to treatment, stress may be considered as a contributing factor, and treatments that attempt to improve a person's mental health may be pursued such as psychotherapy.

Prevention & Prophylaxis

There is no specific prevention for seborrheic dermatitis. Instead, taking control of environmental factors and triggers like illness and stress is the best preventive method. Because emotional distress is frequently a strong factor in skin problems and should be addressed, preventive methods can include stress management techniques.

Because topical products containing alcohol are suspected of aggravating the condition, a person should be wary of using such products in excess. Sun exposure may be an important component of seborrheic control as flare-ups often occur in winter; therefore, it may be advisable to spend adequate time in the sun.

Vitamin D supplementation is thought to be helpful as well. A good multi-vitamin/mineral supplementation can be efficacious to some individuals, as well as removal of sugar products from the diet, because yeast that may cause seborrheic dermatitis is known to feed upon sugar.