What Is the Cause of Seborrheic Dermatitis?

Seborrheic dermatitis, also known as seborrheic eczema, is a chronic papular scaly inflammatory skin disease that occurs in areas rich in sebaceous glands. The disease is more common in adults and newborns, and occurs in areas rich in sebaceous glands such as the head, face, and trunk.

Basic Information

nickname

Seborrheic eczema

English name

seborrheic dermatitis

Visiting department

dermatology

Multiple groups

Adult, newborn

Common locations

Sebaceous glands in head, face and trunk

Common causes

May be related to excessive secretion of sebaceous glands and Malassezia

Common symptoms

Greasy scales or crusts on erythema, symmetrically distributed, mild itching

Causes of seborrheic dermatitis

The cause of this disease is not completely clear. The onset of seborrheic dermatitis may be related to the effects of seborrhea, microorganisms, neurotransmitter abnormalities, physical climate factors, nutritional deficiencies, and drugs. In recent years, the relationship between O. sphaeroides and seborrheic dermatitis has been valued, and it is believed that it plays an important role in the pathogenesis of seborrheic dermatitis. In addition, mental factors, dietary habits, B vitamin deficiencies, and alcohol addiction may also affect the occurrence and development of the disease. A widespread and stubborn seborrheic dermatitis can be an important skin symptom of HIV infection.

Clinical manifestations of seborrheic dermatitis

Skin lesions mainly appear in the scalp, eyebrow arch, nasolabial folds, cheeks, behind the ears, upper chest, interscapular region, umbilicus, vulva and groin. The initial manifestations are inflammatory pimples around the hair follicles, and later, as the disease progresses, it can appear as clearer, slightly yellowish dark red patches, which are covered with greasy scales or crusts. Consciously mild itching. Skin lesions that occur in the trunk are often circular. Most skin lesions start from the scalp and gradually spread downward. In severe cases, the whole body can spread and develop into erythroderma.

Infant seborrheic dermatitis usually occurs 2 to 10 weeks after birth. The scalp is covered with greasy yellow-brown scales and the base is flushed. The eyebrow arch, nasolabial folds, and back of the ear may also be affected, showing as greasy and fine scaly red patches. It usually gradually decreases and heals within 3 weeks to 2 months. For those who are persistent, the possibility of atopic dermatitis should be considered.

Differential diagnosis of seborrheic dermatitis

The diagnosis is based on typical clinical symptoms and signs without difficulty. Should be distinguished from:

Head and face psoriasis

The damage is scattered into flakes, with well-defined boundaries, thick scales, uneven contact, hair does not fall out, and short hair gathered into a bundle. In severe cases, the damage can be connected into a large piece, extending to the front hairline, and invading a few centimeters of forehead. Scaling off the scales has a thin film phenomenon (that is, scaling is scraped off, and a red shiny film underneath) and bleeding phenomenon (that is, lightly scraping the film may appear at small bleeding points). The thin film phenomenon and bleeding phenomenon are important for psoriasis damage. feature.

2. Rose pityriasis

Occurs on the neck, torso, and proximal extremities, with oval-shaped macula, slightly yellow in the center, slightly raised at the edges, reddish, and covered with white pityriae-like scales. It is a single lesion at the beginning, called a maternal spot; the maternal spot becomes larger, reaching 2 to 5 cm or larger in diameter, and sometimes 2 to 3 maternal spots may appear at the same time, and smaller red spots may appear one to two months later. Occurs in the trunk. The long axis of the rash is consistent with the skin pattern. Generally, it can resolve on its own in 4 to 6 weeks without recurrence.

3. Ringworm

Lesion edges are bulging and narrow. The boundaries are clear, and there is a circular wound that heals from the center to the surrounding area. Itching is obvious, and patients often have a history of hand and foot onychomycosis.

4. erythematous pemphigus

Mainly distributed in the middle of the face, neck, chest and back. Beginning with symmetrical erythema on the face, covered with scales and crusts, blisters appeared on the basis of erythema behind the neck and back of the chest, and rash formed after rupture, and the Nissl sign was positive.

Seborrheic Dermatitis Treatment

Seborrheic dermatitis in infants is usually self-healing, and seborrheic dermatitis in adults is often a chronic recurrent process that usually requires long-term repeated treatment.

General processing

Regular life, adequate sleep, adjust your diet, eat more vegetables, limit fatty and polysaccharide diets, avoid alcohol and spicy foods, and avoid excessive stress.

2. External use

(1) Glucocorticoids It is mainly used for severe inflammatory skin lesions. It can be coated with medium-effect or strong glucocorticoid preparations. The effect is good, but it should not be used for a long time, especially on the face. Low-efficiency glucocorticoids (such as hydrocortisone) are less effective and are suitable for infants and young children.

(2) Antibacterial drug: Apply 2% erythromycin ointment or gel, 5% metronidazole cream or cream containing 1% chloramphenicol and 0.1% dexamethasone.

(3) Selenium sulfide lotion has the function of killing fungi and inhibiting bacterial growth, and can also reduce sebum secretion and fatty acid content in sebum.

(4) Zinc thiopyridine lotion Zinc thiopyridine shampoo has a concentration of 1% to 2%. In addition to the scalp, it can also be used in other parts, such as the face, eyebrow arch and trunk. Do not use on the edge of the eyelid to avoid irritation to the eyes. Apply the medicine to the affected area, leave it for 1 to 2 minutes and wash it off with water. Apply once or twice a day. When the symptoms have been controlled, change to once a day, but it must be continued to prevent recurrence. The shampoo has an inhibitory effect on the proliferation of epidermal cells. In addition, it has a broad-spectrum antibacterial effect and can inhibit the growth of P. ovale.

(5) Antifungal preparations Antifungal preparations, especially imidazole drugs, have better curative effects. Shampoos or creams containing ketoconazole (2%), itraconazole, econazole, clotrimazole, miconazole, oxconazole, isoconazole or cyclopiramide and Binafine (1%) preparation. In addition to antifungal preparations, antifungal agents also have various effects such as anti-inflammatory, antibacterial, and inhibition of cell wall lipid formation.

(6) Sulfur and / or salicylic acid lotion and other sulfur and / or salicylic acid have bacteriostatic and anti-dandruff effects, and have a certain effect on this disease, but they are not as good as those of zinc pyrithione and selenium sulfate And irritating. Coal tar preparations have anti-inflammatory, antibacterial, and anti-mitotic effects, but are colored, odorous, and irritating, so they are usually used only on the scalp.

3. Internal use

(1) Glucocorticoids, such as prednisone, are used to treat patients with large skin lesions and severe inflammation. The course of treatment is usually limited to 7-10 days, and should not be too long.

(2) Tripterygium glycosides are suitable for patients with obvious inflammation and large range. The effect is better when combined with a small dose of glucocorticoids.

(3) Antibiotics Seborrheic dermatitis lesions with severe inflammation often have bacterial infections (mainly Staphylococcus aureus infections), and sometimes even pustules and enlarged cervical lymph nodes. Appropriate use of antibiotics, such as tetracycline or erythromycin.

(4) B vitamins include vitamin B ₂ , vitamin B 6 and multivitamin B, which are taken orally for a long time.