Atopic dermatitis (AD) is a common, chronic, recurrent, multifactorial inflammatory skin disease characterized by intense itching. The disease affects people of all ages and ethnicities, has a significant impact on the psyche of patients. The estimated prevalence of AD is 15–20% in children and 7–10% in adults. Atopic dermatitis is associated with an increased risk of many comorbidities, including food allergy, asthma, allergic rhinitis, and psychiatric disorders.
Pathogenesis of atopic dermatitis
The pathophysiology is complex and still not fully understood. It involves a strong genetic predisposition, epidermal dysfunction and inflammation caused by immune mechanisms. The results of numerous studies have shown that Langerhans cells found in the epidermis, dendritic cells present in the dermis, immunoglobulin E (IgE) and T lymphocytes play a key role in the immune mechanism. There is growing evidence that atopic dermatitis involves multiple immune pathways. The non-immune mechanisms of AD include disturbances in the metabolism of unsaturated fatty acids. Reducing the activity of the delta-6-desaturase enzyme and thus inhibiting the conversion of linolenic acid to γ-linolenic acid. As a result, cell division disorders in the epidermis are disturbed, which leads to a significant dryness of the skin and an increase in its sensitivity to external irritants. The mechanisms responsible for the onset and severity of atopic dermatitis include skin barrier dysfunction and atopic substrate. In patients with atopic dermatitis, the functions of intercellular lipids in the stratum corneum of the epidermis are impaired due to abnormal lowering of ceramides. Continuous scratching can have a significant impact on a patient’s quality of life.
Symptoms of atopic dermatitis
- itchy skin
- characteristic localization of skin lesions (depending on age
- chronic and relapsing course
- dry skin
- itching when sweating
- follicular keratosis, or ichthyosis
- positive history of familial atopy
- early onset of change
- prone to recurrent skin infections
- cataracts
- discoloration of the eyelids and dark circles around the eyes
- recurrent conjunctivitis
- intolerance to certain foods
- wool intolerance
- exacerbation of skin lesions after stress
Pharmacotherapy of atopic dermatitis
Currently, there is no effective remedy that would eliminate the disease completely, but the growing number of innovative and targeted therapies offers hope for disease control, including in severely ill patients. Treatment is very difficult and is based on testing various ointments / creams and oral formulations in order to select the agent with the best effectiveness.
The skin barrier function is impaired in patients with atopic dermatitis. As a result, there is a tendency to itchiness and breakouts that appear after contact with irritants. Therefore, to prevent this type of situation, supportive therapy should be applied, consisting in the free use of emollients, softening and moisturizing, eg Diprobase, Oilatum, Physiogel, Xerial. These preparations create a protective layer on the skin, preventing the epidermis from losing water, which leads to increased hydration. We should use them immediately after bathing, because then there is the highest water content in the skin.
In AD, the main methods of treating inflammation are topical corticosteroids and topical calcineurin inhibitors, while in the case of skin barrier dysfunction, topical moisturizers are used.
Topical treatment of atopic dermatitis
Glucocorticosteroids (GKS) (Clobetasol Propionate – Dermovate, Betamethasone Dipropionate – Diprosone, Fluticasone Propionate – Cutivate)
The use of topical corticosteroids is the first line treatment for relapses of atopic dermatitis. They reduce the release of inflammatory mediators and pro-inflammatory cytokines, inhibit the expression of adhesion factors in various cells, both in cells of the immune system, fibroblasts, endothelial cells, and inflammatory cells. They show a strong anti-inflammatory, immunosuppressive and anti-proliferative effect. In the case of long-term topical application of glucocorticosteroids, there is a high risk of local side effects in the form of skin changes, such as: atrophy of the epidermis and dermis, dilation of blood vessels (telangiectasia), skin stretch marks, skin discoloration and discoloration, hirsutism, and posteroid acne. Therefore, you should carefully follow the dosage prescribed by your doctor in order to avoid unpleasant side effects.
- Calcineurin inhibitors (pimecrolimus, tacrolimus, cyclosporin A)
Pimecrolimus, tacrolimus and cyclosporin A are topical calcineurin inhibitors that may be used in combination with topical corticosteroids as first line therapy. The mechanism of their action is based on inhibiting the production of pro-inflammatory cytokines and reducing the sensitivity of T lymphocytes to antigens.
Ultraviolet phototherapy is an effective method of treating severe atopic dermatitis in patients over 12 years of age. Ultraviolet radiation exerts an immunosuppressive effect, the strength of which depends on the type and wavelength.
Antihistamines
H1-histamine receptor antagonists: clemastine (Clemastin), antazoline (Phenazolinum), dimetinden (Fenistil), promethazine (Diphergan), hydroxyzine (Hydroxizinum), cyproheptadine (Peritol), ketotifen (Zaditen, Pozitan). These substances have a number of side effects, including: dry mouth, visual disturbances, constipation, difficulty urinating, drop in blood pressure, sleepiness, disturbance in concentration and psychophysical activity.
Second generation antihistamines include: cetirizine (Zyrtec, Amertil, Allertec), loratadine (Aleric, Loratan, Claritine). Second-generation antihistamines are characterized by high selectivity in relation to the histamine H1 receptor, low lipophilicity and little influence on the CNS activity, and thus show significantly fewer side effects.
The treatment of atopic dermatitis, despite the wealth of available therapeutic agents, is still a disease in which there is no effective remedy. Adequate compliance with the doctor’s recommendations can significantly reduce the symptoms of atopic dermatitis. Skin softeners used in early infancy, as well as an adequate diet, can help prevent atopic dermatitis.
Literature
- Woldan-Tambor, J. B. Zawilska, Atopic dermatitis (AD) – a problem of the 21st century, Department of Pharmacodynamics, Medical University of Lodz,
- Tamagawa-Mineoka and Norito Katoh, Atopic Dermatitis: Identification and Management of Complicating Factors,
- Neha Puar, Raj Chovatiya, Amy S. Paller, New treatments in atopic dermatitis
