Anagen
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Anagen is the first and most active phase of the hair growth cycle, during which intensive proliferation of hair matrix cells and synthesis of keratin — the primary protein building the hair shaft — occur. During this period the hair follicle (the anatomical unit responsible for producing the hair) remains deeply embedded in the dermis or subcutaneous tissue, and its metabolic activity is the highest throughout the hair cycle. The duration of anagen determines the maximum hair length, and disturbances of this phase are a key mechanism in the pathogenesis of many types of hair loss. In a healthy person, the majority of hairs on the scalp are in the anagen phase.
Atopic dermatitis of the scalp – causes
The pathogenesis of atopic dermatitis is complex and results from the overlap of genetic, immunological, and environmental factors. A key role is played by impairment of the epidermal barrier function, which leads to increased water loss through the skin (so-called TEWL – transepidermal water loss) and easier penetration of allergens and irritants.
The most important causes and risk factors for the development of atopic dermatitis of the scalp include:
- genetic predispositions, especially mutations in the filaggrin gene (FLG), a protein responsible for the proper structure of the epidermis
- immunological disorders, particularly excessive activation of Th2-type T lymphocytes
- family history of atopy, including atopic dermatitis (AD), asthma, or allergic rhinitis
- environmental factors, such as air pollution, tobacco smoke, or low humidity
- contact or inhalant allergens, e.g., house dust mites, animal dander, or plant pollens
- irritants, including harsh detergents, certain hair care products, or frequent washing of the scalp
In many patients, disease symptoms also worsen under the influence of psychological stress, hormonal changes, and skin infections. Disturbance of the skin microbiome also plays an important role – particularly excessive colonization by Staphylococcus aureus bacteria, which can amplify the inflammatory response.
Atopic dermatitis of the scalp – what does it look like
Symptoms of atopic dermatitis of the scalp result mainly from chronic inflammation and disruption of the epidermal barrier function. The clinical picture may vary depending on the patient’s age, disease severity and the presence of exacerbating factors.
The most common symptoms include:
- intense scalp itching, often worse at night
- dryness of the skin (xerosis) and a feeling of tightness
- erythema, i.e., redness of the skin
- skin scaling, which can resemble dandruff
- small inflammatory papules or erosions resulting from scratching
- thickening of the skin (lichenification) in the course of chronic inflammation
Because of intense itching, patients often scratch the skin, which can lead to:
- secondary bacterial or fungal infections,
- formation of crusts and erosions,
- weakening or thinning of the hair at the site of pronounced inflammation.
Atopic changes on the scalp can involve the entire hairy scalp or appear in specific areas, most often:
- in the occipital area,
- behind the ears,
- at the border between the hairy scalp and the forehead.
Because of the similarity of symptoms, the differential diagnosis should include, among others:
- seborrheic dermatitis,
- scalp psoriasis,
- contact dermatitis,
- fungal infection of the hairy scalp.
Atopic dermatitis of the scalp – how to treat
Treatment of atopic dermatitis of the scalp is symptomatic and long-term, because the disease has a chronic and relapsing course. Therapy focuses on restoring the proper function of the epidermal barrier, reducing inflammation and limiting itching.
The basis of management is systematic scalp care:
- use of mild dermatological shampoos, without strong detergents (e.g., SLS, SLES)
- regular use of emollient preparations that restore the skin's lipid barrier
- avoiding irritants, such as aggressive hair styling cosmetics
Pharmacological treatment includes:
- topical glucocorticosteroids of appropriate potency
- calcineurin inhibitors (e.g., tacrolimus, pimecrolimus)
- antipruritic and anti-inflammatory agents
- in case of superinfection – antibiotics or antifungal medications
In patients with severe disease, systemic treatment may be necessary, including:
- immunomodulatory drugs,
- dermatologic phototherapy,
- biologic therapies (e.g., monoclonal antibodies that inhibit interleukins responsible for the inflammatory response).
For chronic skin lesions, dermatological procedures that support skin regeneration may also be helpful, such as laser therapies, skin regenerative procedures or procedures that improve the epidermal barrier function. Although they are not the basis of treatment for atopic dermatitis, they can support skin repair processes and improve patient comfort.
Long-term disease control, identification of triggering factors and systematic skin care are of key importance in therapy, as they reduce the risk of relapses and improve patients' quality of life.
Atopic dermatitis of the scalp – scalp care in atopic dermatitis
Proper scalp care is one of the most important elements in controlling atopic dermatitis (AD). In AD there is damage to the epidermal barrier, increased water loss, and greater skin susceptibility to irritants and allergens. For this reason, daily care should focus on rebuilding the hydrolipidic barrier, reducing skin dryness, and limiting inflammation and itch.
The basis of care is the use of mild cleansing products designed for atopic skin. Shampoos used in AD should have a physiological pH and as simple a composition as possible. It is recommended to avoid strong detergents such as SLS (sodium lauryl sulfate) and SLES (sodium laureth sulfate), which can further damage the epidermal barrier and increase irritation. Preferable are cleansing agents based on mild surfactants, e.g. cocamidopropyl betaine or plant-derived glucosides.
An important element of therapeutic care is the use of emollient preparations. Emollients contain ingredients that:
- replenish epidermal lipids (e.g. ceramides, cholesterol, fatty acids),
- reduce transepidermal water loss,
- decrease sensations of itch and skin tightness.
For the scalp they may take the form of light lotions, emulsions, or special scalp formulations that do not weigh the hair down and are easy to spread.
In scalp care for AD it is also recommended to:
- wash the scalp with lukewarm, not hot, water, because high temperature intensifies itch and skin drying,
- gently dry the scalp with a towel, without vigorous rubbing,
- limit the use of styling products that may contain alcohol, fragrances or other potential allergens,
- avoid frequent hair dyeing or the use of strong chemical treatments.
In some patients it is also beneficial to use preparations containing substances that soothe inflammation, such as panthenol, allantoin, niacinamide or plant extracts with soothing effects.
In cases of severe itching it is very important to limit scratching of the skin, because it leads to epidermal damage, secondary bacterial infections and worsening of inflammation. Therefore, in AD therapy the concurrent use of anti-itch preparations and regular skin moisturization is often recommended.
Systematic and appropriately selected scalp care can significantly reduce the frequency of disease flare-ups, improve patient comfort and support the effects of dermatological treatment. In clinical practice it is regarded as one of the fundamental elements of long-term management of atopic dermatitis.
