Atopic Dermatitis – Know It to Deal with It

Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects both children (15–20%) and adults (2–5%). It can be considered a lifelong disease with onset in pre-infantile (<2 years of age), childhood (2–12 years of age), adolescence (12–18 years of age), or adulthood (>18 years of age), and a separate subgroup with onset in the elderly (⩾60 years of age) has recently been described. Clinically, it presents as eczema, with clinical lesions traditionally classified as “acute” (oozing, edema, and erythema) or “chronic” (dyspigmentation, xerosis, and lichenification). However, because AD is a chronic relapsing condition, both types of lesions may coexist during flare-ups. Pruritus is a hallmark of AD and excoriations secondary to scratching are often present, which can lead to bacterial and viral superinfections due to compromised skin integrity. The defective skin barrier allows irritants and allergens to penetrate the skin and cause inflammation through an overactive Th2 response (with increased cytokines IL-4, IL-5) in acute lesions and Th1 response (with IFN-gamma and IL-12) in chronic lesions. Skin scratching also stimulates keratinocytes to release inflammatory cytokines such as TNF-alpha, IL-1 and IL-6. The decrease in antimicrobial peptides (human beta-defensins, cathelicidins) in the epidermis of atopic patients also contributes to superinfections such as those by Staphylococcus aureus, observed in over 90% of patients with atopic dermatitis. S. aureus can worsen the inflammation of atopic dermatitis lesions and lead to secondary infections. In addition, there is significant water loss through the epidermis in AD.    

AD is thought to be associated with other IgE-associated disorders such as allergic rhinitis, asthma, and food allergies. The etiology is complex, involving genetic and environmental factors that lead to abnormalities in the skin and immune system. If a parent has the disease, there is a greater than 50% chance that their children will also have the disease, while if both parents have the disease, the chance increases to 80%.

Atopic dermatitis is part of the atopic triad (atopic dermatitis, allergic rhinoconjunctivitis, and asthma), and patients presenting with this triad have a defective barrier of the skin, which is susceptible to xerosis and environmental irritants and allergens, but also of the upper respiratory tract and lower respiratory tract.

There are guidelines on the treatment of AD in adults and children, and typical treatment strategies include treating visible skin lesions with topical anti-inflammatory drugs such as corticosteroids and calcineurin inhibitors in combination with frequently applied emollients to minimize the impact of skin barrier dysfunction.

The use of corticosteroids, however, has numerous side effects, including an inhibition of the immune system which increases the risk of bacterial and viral superinfections.

In the next article we will present a natural remedy against itching and inflammation caused by this pathology.

References

Kolb L, Ferrer-Bruker SJ. Atopic Dermatitis. 2021 Aug 13. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–.

Girolomoni G, de Bruin-Weller M, Aoki V, Kabashima K, Deleuran M, Puig L, Bansal A, Rossi AB. Nomenclature and clinical phenotypes of atopic dermatitis. Ther Adv Chronic Dis. 2021 Mar 26;12:20406223211002979.