Chronic dermatosis: features of scalp care

Ekaterina Bardova, National Medical Academy of Postgraduate Education named after. P. L. Shupika (Ukraine)

Seborrheic dermatitis

This is a chronic inflammatory skin disease with a relapsing course, associated with qualitative and quantitative changes in sebum. Most often it develops in areas rich in sebaceous glands: on the face, chest, interscapular area and scalp.

The etiology and pathogenesis of this disease are still unknown. Due to hereditary predisposition, hormonal disorders, neurohumoral, metabolic and immune changes, a qualitative and quantitative change in sebum occurs, as well as a violation of the barrier function of the skin, which leads to the activation of opportunistic flora and the development of rashes on the skin characteristic of this pathology.

Currently, an important role in the etiology of seborrheic dermatitis is assigned to the lipophilic yeast-like fungus Pityrosporum ovale (Malassezia furfur), which is an opportunistic microorganism that lives in the stratum corneum of the epidermis and a constant component of the microflora of healthy skin in most people. The microflora of the scalp normally contains 30–50% P. ovale; with dandruff, this number increases to 75%, and with moderate and severe forms of seborrheic dermatitis, the concentration of P. ovale reaches 90%. Some authors are inclined to believe that seborrheic dermatitis is a hypersensitivity reaction to this type of fungus.

Diseases of internal organs, especially diseases of the endocrine system, play a great role in the development of seborrheic dermatitis. The sebaceous glands are simple alveolar glands with a holocrine type of secretion. They begin to function in the prenatal period. In infants they are fully formed and developed. Seborrheic dermatitis first appears in the neonatal period and can be considered a reaction to stimulation by maternal hormones; it resolves on its own and does not require treatment. During puberty, the sebaceous glands increase in size and their secretory activity increases, reaching a maximum by 18–25 years. It is during this period that the next peak in the development of the disease is observed.

The fact that men suffer from seborrheic dermatitis more often confirms the assumption that the activity of the sebaceous glands is under the control of androgens. Sebum production in men is stimulated by testosterone, dehydroepiandrosterone and androstenedione. In women, sebum production is affected by even a slight increase in circulating androgen levels.

It is known that in patients with diseases of the central and autonomic nervous system, as well as against the background of emotional stress, seborrheic dermatitis develops more often, is more severe and is difficult to treat.

Some authors pay special attention to the state of the gastrointestinal tract (unbalanced diet, decreased motility, changes in the enzymatic activity of the stomach and intestines), the presence of foci of chronic infection and the negative influence of the external environment (use of alkaline detergents).

There are three clinical forms of seborrheic dermatitis:

• The dry form of seborrheic dermatitis is characterized by the appearance of small flour-like white scales on the scalp. Sometimes peeling can take on a large-plate character, but without signs of visible inflammation. Patients often experience thinning and thinning hair. Subjectively, patients complain of a burning sensation and itching;
• The fatty form is characterized by the appearance of large-plate scales of a yellowish color against the background of excess sebum secretion. Hair with this form is oily, shiny, and sticks together in strands;
• The mixed form is characterized by the appearance of inflammatory spots of a pinkish-yellowish color, with clear boundaries and peeling.

Contact dermatitis

It is an inflammatory disease caused by direct skin contact with an irritating agent. It can be caused by both immune and non-immune mechanisms. In the first case we are talking about allergic contact dermatitis, in the second we are talking about simple contact dermatitis. Simple contact dermatitis is caused by irritating substances.

Most often, the occurrence of contact dermatitis is associated with improper use or poor quality of hair dyes and care products, as well as after the use of certain shampoos or products for the treatment of head lice. The clinical picture of contact dermatitis on the scalp is represented by slight hyperemia and peeling.

Psoriasis

This is a chronic dermatosis of a multifactorial nature, characterized by impaired keratinization and hyperproliferation of epidermal cells, followed by the development of inflammation in the dermis.

Psoriasis often develops on the scalp and can exist in this isolated form for quite a long time. Often its first manifestation is profuse peeling without pronounced inflammatory changes on the skin. In the differential diagnosis of seborrheic dermatitis (if the doctor does not have a family history), the absence of hair thinning or baldness, despite the presence of many years of flaking of the scalp, and the appearance of plaque elements, which have a number of features compared with rashes located on other parts of the body, helps. In psoriasis, their boundaries are less clear than the outlines of lesions on the body; they are covered with grayish-yellow scales that fit more tightly, and therefore the psoriatic triad does not always have a classic appearance and instead of pinpoint bleeding, a weeping bleeding surface may form.

Characteristic signs of psoriasis of the scalp, on the basis of which it can be differentiated from seborrheic eczema, are skin lesions at the border with the scalp, the so-called psoriatic crown, absence of hair loss, less tendency to follicular arrangement of elements, greater dryness of scales, rare occurrence of pityriasis peeling. Also, when differentially diagnosing psoriatic rashes from seborrheic eczema, one should take into account the color of the rashes (with seborrheic eczema it will be more yellow), vagueness of the lesions, weeping, especially after scratching, more frequent occurrence of itching, and the absence of the psoriatic triad. Family history must also be taken into account.

Some authors identify a special form - sebopsoriasis, which is considered as a transitional form between psoriasis and seborrheic dermatitis or as a combination of two pathologies. Psoriatic rashes are peculiar on other seborrheic areas of the skin - on the face and sternum, especially in people prone to seborrhea. It is characterized by the presence of plaques with scales that are difficult to separate, but they have a greasy consistency and a yellowish color, and are also characterized by a greater tendency to exudate, and not as clear boundaries as with ordinary plaque forms.

Seborrheic dermatitis and psoriasis are chronic dermatoses, therefore, along with systemic treatment, it is necessary to use local drugs.

Features of care and treatment

The basis of caring for the scalp and hair is maintaining their cleanliness:

• It is not recommended to use soap, as well as shampoos with anionic surface substances, as they lead to swelling of the hair cuticle scales, causing the hair to become tangled and difficult to comb;
• It is not recommended to use a hair dryer, as this leads to increased sebum secretion, as well as combing hair in an unnatural direction, pulling it into tight “tails”;
• Hair dyes are strictly prohibited during an exacerbation period.

For the treatment of skin diseases of the scalp, accompanied by desquamation phenomena, the use of combined products is indicated, primarily medicinal lotions, ointments, creams and shampoos, the action of the components of which is aimed at exfoliating the keratinizing epidermis, as well as normalizing keratinization processes.

In addition, during the period of remission, caring for the scalp is of great importance. For this purpose, it is most advisable to use shampoos with targeted action, with an antimycotic and exfoliating effect.

Active additives, thanks to which the desired effect is achieved, can be divided into separate groups according to their mechanism of action: antifungal, keratolytics, cytostatics, corticosteroids, antipruritics and anti-inflammatory drugs. In particular, corticosteroids are commonly prescribed for seborrheic eczema and severe forms of seborrheic dermatitis.

Active substances: who is who?

The use of medicated shampoos primarily prevents the growth of fungi, slows down the rate of division of basal cells, reduces peeling of the skin, and reduces the secretion of sebum. To increase efficiency, several active substances are introduced into medicinal shampoos that affect the mechanisms of increased desquamation.

Salicylic and glycolic acids and papain are used as keratolytics. These components regulate the process of keratinization of basal epidermocytes, slowing down the rate of their division. Also used for this purpose are zinc pyrithioneate, selenium disulfide, tar, octopyrox, ciclopirox, ichthyol, tar, and sulfur.

Among the many antifungal ingredients in shampoos, preference is given to those that can accumulate in the epidermis and also have anti-inflammatory and keratoregulating effects. Of the antifungal drugs that meet these requirements, ketoconazole, clotrimazole, climbazole, miconazole, ciclopirox, piroctone olamine, selenium disulfide, pyrithioneate and zinc thiosalicylate have proven themselves to be excellent.

The most common ingredient in medicated shampoos is ketoconazole. The main mechanism of its action is a violation of the synthesis of membrane ergosterol, which provides a fungistatic effect. Shampoos based on ketoconazole are safe and allow you to create a high local concentration of the antimycotic in the affected area of the skin and hair. However, in some cases there is tolerance to it. Ketoconazole is used in preparations in the form of shampoos “Nizoral”, “Sebozol”, “Dermazol”, “Kenazol”, “Keto Plus”, etc.

In addition to antifungal medicinal substances, cosmetic substances are effectively used in shampoos.

Zinc pyrithioneate has moderate fungistatic activity; in addition, it inhibits the growth of gram-positive and gram-negative bacteria, and has pronounced antimycotic, antibacterial and anti-inflammatory properties.

The exact mechanism of the anti-inflammatory effect of zinc salts has not yet been fully studied. It is believed that under the influence of zinc, the release of inflammatory mediators interleukin-I and interleukin-IV is reduced. A number of researchers claim that in most dermatoses, the level of zinc in the epidermis and papillary layer of the dermis is reduced.

Ciclopirox has a fungicidal effect (for example, on fungi of the genus Malassezia, ciclopirox has a fungicidal effect three minutes after the start of contact).

Climbazole, selenium disulfide and birch tar, which is a product of dry distillation of birch bark, have a disinfectant, insecticidal and local irritant effect due to the content of phenol, toluene, xylene, resins and other substances. Tar and ichthyol, which are kerator-reducing agents, normalize the cell renewal cycle and have a moderate antifungal effect. Tar is also known to reduce keratinocyte proliferation and reduce infiltration. Side effects include increased photosensitivity, and given its applicability in outpatient settings and, in particular, in cosmetology, a characteristic odor and a tendency to slightly dye the hair orange should be noted, which limits the use of tar.

Many medicated shampoos contain salicylic acid, which suppresses the secretion of sebaceous and sweat glands. In low concentrations it has a keratoplastic effect, and in high concentrations it has a keratolytic effect. Salicylic acid has weak antimicrobial activity and, along with tar, is involved in the process of exfoliating cells from the surface of the skin. Traditionally, combination prescriptions containing salicylic acid and antimicrobial drugs are used to treat chronic dermatoses accompanied by desquamation.

The use of extracts from medicinal plants, including essential oils, which have a whole range of actions, is quite effective. Thus, essential oils of cypress, juniper, rosemary, eucalyptus, tea tree, cajuput have antifungal, anti-inflammatory and antipruritic effects, and also slow down the division of keratinocytes.

When the pathological process is localized in the scalp area, the most convenient form of treatment and care is the use of medicated shampoo, which should solve the following problems:

• suppress the growth of yeast fungi;
• eliminate peeling;
• have an antiproliferative effect.

Neither monograph drugs (tar, salicylic acid, selenium sulfide, zinc pyrithione, sulfur) nor non-monograph drugs (climbazole, octopirox, ketoconazole) are capable of individually solving all the tasks.

In recent years, a wide variety of medicinal shampoos have appeared on pharmacy shelves, which are created taking into account the characteristics of the nature of the damage to the scalp, the type and condition of the hair (dry, normal, oily, dyed, etc.). In order for the treatment to be not only effective, but also to ensure a lasting result, you must follow the instructions for use of the drug. First of all, this concerns the exposure time, otherwise the active ingredients of the shampoo will not be able to give the desired effect. Active treatment of dandruff continues for 3–6 weeks, after which shampoos should be gradually discontinued.

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Thus, the prescription of care for the scalp in patients with chronic dermatoses should be differentiated, pathogenetically substantiated, which is of great practical importance in the case of long-term therapy, in order to lengthen the period of remission and improve the quality of life of patients.

First published: Les Nouvelles Esthetiques Ukraine, No. 5 (87), 2014