Seborrheic dermatitis and dandruff

Seborrheic dermatitis is a chronic recurrent skin disease that develops in seborrheic areas and large folds, manifested by erythematosquamous and follicular papular-squamous rashes and occurs as a result of the activation of saprophytic microflora.

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What causes seborrheic dermatitis?

Seborrheic dermatitis is caused by the proliferation of the lipophilic yeast-like fungus Pityrosporum ovale (Malassezic furfur) in the mouths of hair follicles. This fungus saprophytes on skin areas abundantly supplied with sebaceous glands. The frequency of its isolation in healthy people ranges from 78 to 97%. However, with certain changes in the protective biological system of the skin surface, P. ovale receives favorable conditions for reproduction and exhibits the properties of a pathogenic fungus. Endogenous factors predisposing to the development of seborrheic dermatitis include seborrhea, endocrine diseases (diabetes mellitus, thyroid pathology, hypercorticism, etc.). Immunosuppression of any etiology plays a significant role in the pathogenesis of seborrheic dermatitis, as well as other diseases caused by opportunistic yeast-like fungi. Thus, seborrheic dermatitis is an early marker of HIV infection. Its symptoms are often observed against the background of severe somatic diseases, hormonal disorders, in patients with atopic dermatitis.

Symptoms of Seborrheic Dermatitis

Depending on the location and severity of the inflammatory process, several clinical and topographic types of seborrheic dermatitis are distinguished:

1. Seborrheic dermatitis of the scalp:
   • "dry" type (simple dandruff);
   • "oily" type (stearic or waxy dandruff):
   • "inflammatory" (exudative) type.
2. Seborrheic dermatitis of the face,
3. Seborrheic dermatitis of the trunk and large folds
4. Generalized seborrheic dermatitis.
5. Seborrheic dermatitis of the scalp
6. Dry type (simple dandruff), or pityriasis sicca

Dandruff is a chronic lesion of the scalp, characterized by the formation of parakeratotic scales without signs of inflammation. In these cases, as in ichthyosis, the scales are the primary rash elements. The appearance of dandruff is the earliest sign of the development of seborrheic dermatitis of the scalp.

Dandruff appears as small foci, mainly in the occipital-parietal region, but can quickly spread to the entire scalp. The boundaries of the lesion are unclear. Hyperplasia and hypersecretion of the sebaceous glands characteristic of seborrhea are absent. Peeling is bran-like, the scales are dry, loose, grayish-white, easily separated from the skin surface and dirty the hair, as well as outerwear. Hair is also dry. Typically, there are no inflammatory phenomena and subjective disorders.

"Fat" type, or pityriasis steatoides

Oily (stearic, or waxy) dandruff occurs against the background of increased sebum secretion, so the scales have a greasy appearance, a yellowish tint, stick together, are more firmly held on the skin than with dry dandruff, and can form layers. The scales usually separate from the skin surface in large flakes. The hair looks greasy. Itching, erythema and excoriations may also be observed.

Inflammatory or exudative type

On the scalp, scaly erythema appears, which is slightly infiltrated, and yellowish-pink spotty plaque rashes with clear contours are formed. They can merge into extensive psoriasiform lesions, capturing almost the entire scalp. In the forehead and temples, a clear, slightly elevated edge of the lesions is located below the hairline in the form of a "seborrheic crown" (corona seborrheica Vnnae). The surface of the elements is covered with dry bran-like or greasy scales. Patients are bothered by itching.

In some patients, serous or milky scaly crusts of a yellowish-gray color with an unpleasant odor appear on the surface of the lesions; after removal, a wet surface is exposed.

The process often spreads from the scalp to the forehead, neck, auricles and parotid areas. Deep, painful cracks may be observed in the folds behind the auricles, and regional lymph nodes sometimes become enlarged.

Seborrheic dermatitis of the face

The medial part of the eyebrows, the bridge of the nose, and the nasolabial folds are affected. Itchy, spotty, plaque-like, flaky, pinkish-yellowish elements of various sizes and shapes are observed. Painful cracks and layered scaly crusts may appear in the folds. The rash on the face is usually combined with lesions of the scalp and eyelids (marginal blepharitis). In men, superficial follicular pustules may also be observed in the moustache area and on the chin.

Seborrheic dermatitis of the trunk

The lesion is localized in the sternum, in the interscapular zone along the spine. The rash is represented by yellowish or pinkish-brown follicular papules covered with greasy scaly crusts. As a result of their peripheral growth and fusion, weakly infiltrated foci are formed with clear large-scalloped or oval outlines, paler in the center and covered with delicate bran-like scales. Fresh dark red follicular papules can be found along the periphery of the foci. Due to central resolution, some plaques can acquire annular, garland-like outlines.

In large folds of skin (axillary, inguinal, anogenital, under the mammary glands, in the navel area) seborrheic dermatitis manifests itself as clearly defined erythema or plaques from pink with a yellowish tint to dark red, the surface of which peels, and is sometimes covered with painful cracks and scaly crusts.

Generalized seborrheic dermatitis

Seborrheic dermatitis foci, increasing in area and merging, can lead to the development of secondary erythroderma in some patients. The skin is bright pink, sometimes with a yellowish or brownish tint, edematous, large folds are exaggerated, cracks and exfoliative peeling are observed. Microvesiculation, weeping (especially in skin folds), and layers of scaly crusts can be observed. Pyogenic and candidal microflora often join. Patients are concerned about severe itching and an increase in body temperature. Seborrheic dermatitis can be accompanied by the development of polyadenitis, deterioration of the general condition of patients, which is an indication for hospitalization.

The course of seborrheic dermatitis is chronic and recurrent, the disease worsens in winter, and in summer there are almost complete remissions. Seborrheic dermatitis not associated with HIV infection, as a rule, is mild, affecting individual areas of the skin. Seborrheic dermatitis associated with HIV infection is characterized by a tendency to a more severe course and generalization, widespread damage to the skin of the trunk, large folds, the appearance of follicular pustules of atypical manifestations (like plaque eczema), a high frequency of generalized seborrheic dermatitis, resistance to therapy, frequent relapses.

Complications of seborrheic dermatitis

Seborrheic dermatitis can be complicated by the following conditions: eczematization, secondary infection (yeast-like fungi of the genus Candida, streptococci), increased sensitivity to physical and chemical irritants (to high temperatures, some synthetic fabrics, external and systemic medications).

Seborrheic dermatitis is diagnosed based on the characteristic clinical picture. Differential diagnostics should be carried out between seborrheic psoriasis, allergic dermatitis, perioral dermatitis, seborrheic papular syphilid, mycosis of smooth skin, lupus erythematosus, clinical keratosis, ichthyosis, cicatricial erythema of the face, manifestation of skin lymphomas on the face and scalp, streptoderma of the scalp and a number of other dermatoses. In case of isolated localization of the process on the scalp, it is also necessary to remember about head lice.

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How to treat seborrheic dermatitis?

The main attention in the treatment of each patient who suffers from seborrheic dermatitis should be paid to identifying individually significant factors in the pathogenesis of seborrheic dermatitis and, if possible, correcting them.

Etiotropic treatment of seborrheic dermatitis involves the systematic use of topical antifungal agents that act on P. ovale. These include ketoconazole (Nizoral) and other azole derivatives - clotrimazole (Clotrimazole, Canesten, Candid, etc.), miconazole (Daktarin), bifonazole (Mikospor), econazole (Pevaryl, etc.), isoconazole (Travogen), etc., terbinafines (Lamisil, etc.), olamines (Batrafen), amorolfine derivatives, zinc preparations (Curiosin, Regecin, etc.), sulfur and its derivatives (selenium disulfide, selenium disulfate, etc.), tar, ichthyol. For the treatment of seborrheic dermatitis of smooth skin and skin folds, these fungicidal drugs are used in the form of cream, ointment, gel and aerosol. When a pyogenic infection occurs, antibacterial drugs are prescribed - creams with antibiotics (Baneocin, Fucidin, Bactroban, etc.), 1-2% aqueous solutions of aniline dyes (brilliant green, eosin, etc.).

When the scalp is affected, these products are used more often in the form of medicated shampoos, which should be used several times a week. The course of medicated shampoos is usually 8-9 weeks. It should be remembered that these shampoos must be used with mandatory foam application for 3-5 minutes, and then washed off.

In case of "dry" type of scalp lesions, it is not advisable to use alkaline soaps and shampoos, as well as alcohol-containing products, since they degrease and dry out the skin, increasing its peeling. The most preferable are shampoos containing azoles ("Nizoral", "Sebozol") or zinc preparations ("Friderm-zinc", "Kerium-cream"), sulfur and its derivatives ("Selezhel", "Derkos from dandruff for dry scalp").

In case of hypersecretion of sebaceous glands, antiseborrheic agents are effective, since removal of the lipid film from the skin means elimination of a favorable environment for the vital activity of P. ovale. It is rational to use detergents containing anionic and nonionic detergent acids (for example, citric acid) and normalizing the pH of the skin surface. For the oily type, the most preferable are shampoos containing azoles {"Nizoral", "Sebozol", "NodeD. S", "NodeD. S. plus"), tar ("Friderm-tar"), ichthyol {"Kertiol", "Kertiol S"), sulfur and its derivatives (shampoo "Derkos from dandruff for oily scalp") and other agents with antifungal activity ("Saliker", "Kelual D. S", "Kerium-intensive", "Kerium gel", etc.).

In the inflammatory type of seborrheic dermatitis, solutions, emulsions, creams, ointments, aerosols containing glucocorticosteroid hormones (Elokom, Advantan, Lokoid, etc.) or combined agents (Pimafucort, Triderm, Travocort) have a rapid therapeutic effect with timely administration of external antifungal agents. It should be emphasized that these drugs are prescribed for a short time for 7-10 days, and fluorinated glucocorticosteroids are not preferred.

Traditionally, keratolytic agents in low concentrations are used to treat seborrheic dermatitis: salicylic acid (for the scalp - shampoos "Fitosilik", "Fitoretard", "Saliker", "Kerium-intensive", "Kerium-cream", "Kerium-gel", "Squafan") and resorcinol. It is rational to use combined external preparations containing antimycotics, glucocorticoids and exfoliants.

After the onset of remission, gentle care of the skin and scalp is recommended. For washing, "soft" shampoos that do not change the pH of the skin surface are recommended ("Ecoderm", "Elusion", "pH-balance", etc.). Preventive washing of the head with detergents containing antifungal agents is also recommended, once every 1-2 weeks.

Individual pathogenetic therapy is of decisive importance for the treatment of severe forms of seborrheic dermatitis. However, it is not always possible to identify and eliminate the factors that play a pathogenetic role in the development of seborrheic dermatitis. Calcium preparations in combination with vitamin B6 are prescribed orally or intramuscularly. In severe, generalized seborrheic dermatitis resistant to external treatment, systemic administration of azole drugs is indicated (Ketoconazole - Nizoral 240 mg / day for 3 weeks or itraconazole - Orungal 200 mg / day for 7-14 days). In acute generalized seborrheic dermatitis, in extreme cases, systemic steroids are prescribed (a rapid clinical effect is usually achieved with 30 mg of prednisolone per day) simultaneously with active external or general therapy with antimycotics. In cases of secondary infection and complications (lymphangitis, lymphadenitis, fever, etc.), broad-spectrum antibacterial drugs are indicated. Sometimes patients with seborrheic dermatitis are prescribed isotretinoin and selective phototherapy (UV-B).