What is Atopic Dermatitis?
Atopic Dermatitis, also frequently termed ‘Atopic Eczema’ or ‘Eczema’, is the most
common chronic inflammatory skin disorder seen in patients globally. Atopic
Dermatitis is characterised by itchy dry lesions and possesses a multifaceted
pathogenesis involving both genetic and environmental underpinnings. Atopic
Dermatitis mostly arises in childhood, with research declaring that approximately
60% of childhood cases begin in the first year of life.
What are the signs, symptoms and clinical manifestations of Atopic
Dermatitis?
Atopic Dermatitis frequently bestows in patients who have what is called an ‘Atopic
Tendency,’ or the ‘Atopic Triad.’ This means sufferers may acquire all three closely
interconnected conditions; Atopic Dermatitis, Asthma and Rhinitis (hay-fever), in a
sequential manner.
Specific to the cutaneous presentation of Atopic Dermatitis, there is quite a disparity
amongst individuals, though the main manifestations involve:
Erythema (redness)
Oedema (swelling)
Crusting
Weeping
Pruritus (itching)
Excoriation from excessive scratching
Lichenification / lichenified plaques (thickened skin)
Xerosis (dryness)
Scaling
Cracking
Fissuring
Vesicles (blisters)
Pigmentary alterations
Erosions
Bleeding
The anatomically affected regions of Atopic Dermatitis are dependent upon the age
range of the sufferer:
3 months – 2 years: the scalp (also commonly termed ‘cradle cap’), cheeks, neck, extremities and trunk are affected, while the diaper region is usually spared.
2 – 12 years: The outer aspects of joints, as well as the wrists, elbows, ankles and knees are generally disturbed.
12-60 years: The affected regions include the head, neck, hands and flexural regions.
60+ years: The flexural regions are usually spared, and it is important to note that a number of differential diagnoses which may mimic Atopic Dermatitis must be excluded.
Atopic Dermatitis and the skin’s barrier
One of the exclusive hallmarks of Atopic Dermatitis is a deficiency in the skin’s
barrier functionality. The Stratum Corneum is composed of corneocytes which are
responsible for secreting intercellular substances (filaggrin). These breakdown into
constituents, such as amino acids (Natural Moisturising Factors) and lipids
(ceramides) which then operate to arrange a barrier layer which defends the
epidermis against environmental insults. But in Atopic Dermatitis patients, there are
numerous alterations and deficiencies in the proteins and the lipids of the Stratum
Corneum, resulting in bacterial colonisation and hence secondary bacterial, viral and
fungal skin infections.
Atopic Dermatitis and the environment
Atopic Dermatitis sufferers will often discover their condition is exacerbated
throughout winter. The water content of the epidermis mirrors the environmental
humidity levels and owing to the reduced humidity levels in the cooler months the skin becomes considerably drier, resulting in impairment of the natural barrier
function and thence the potential for secondary skin infections.
Atopic Dermatitis and COVID-19
COVID-19 has seen numerous alterations in Atopic Dermatitis patients. Alcohol-based sanitisers containing at least 60% ethanol are recommended for hand hygiene, as the alcohol is able to denature proteins and thus inactivate enveloped viruses including coronaviruses. Excess use of sanitisers can lead to skin dryness, itching, burning, erythema, scaling and vesiculation through depletion of skin surface lipids allowing penetration of detergents into the epidermis.
Additionally, it is marked in research that other various factors resultant of the coronavirus are responsible for exacerbating this chronic condition, these include:
Repeated hand washing and sanitising which causes further disruption to the skin’s barrier
Adverse psychological effects which have increased pruritus in Atopic Dermatitis sufferers
Reduced UV exposure in aggregation with high temperatures and low humidity have exerted an immunosuppressive effect on the skin
Greater exposure to indoor pollutants
Reduced routine dermatologic visits
References
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