Atopic dermatitis (Atopic Eczema) Flashcards
What is atopic dermatitis?
topic dermatitis, also called atopic eczema, the most common inflammatory skin disease worldwide, presents as generalised skin dryness, itch, and rash.
What is the epidemiology of atopic dermatitis?
Approximately 230 million people around the world have atopic dermatitis
prevalence is >15% especially in wealthier countries
Who does atopic dermatitis typically affect?
It typically affects people with an ‘atopic tendency’ clustering with hay fever, asthma, and food allergies
All races can be affected; some races are more susceptible to developing atopic dermatitis, and genetic studies are showing marked diversity of the condition’s extent (heterogeneity) between populations.
When does atopic dermatitis usually start?
Atopic dermatitis usually starts in infancy, affecting up to 20% of children. Approximately 80% of children affected develop it before the age of 6 years. All ages can be affected. Although it can settle in late childhood and adolescence, the prevalence in young adults up to 26 years of age is still 5–15%.
What causes atopic dermatitis?
Atopic dermatitis results from a complex interplay between environmental and genetic factors
Current theories identify that atopic dermatitis is primarily a disease of the immune system, with cytokines being critical components to the disease. These cytokines, particularly IL-4 and IL-13 (Th2 pathway cytokines) and IL-22 (the Th22 axis cytokine) cause barrier defects and inflammation that result in the clinical features of eczema.
What is atopy?
Atopy refers to the tendency to asthma, eczema and hay fever. Atopy is mostly inherited (genetic). It is characterised by an overactive immune response to environmental factors.
What does atopic dermatitis look like?
Acute dermatitis is red (erythematous), weeping/crusted (exudative) and may have blisters (vesicles or bullae).
What happens to the appearance of atopic dermatitis over time?
Over time the dermatitis becomes chronic and the skin becomes less red but thickened (lichenified) and scaly. Cracking of the skin (fissures) can occur.
How is atopic dermatitis characterised?
The clinical phenotype of atopic dermatitis can vary greatly, but is characterised by remission and relapse with acute flares on a background of chronic dermatitis.
How does infantile atopic dermatitis first present?
At or shortly after birth, atopic dermatitis may initially present as infantile seborrhoeic dermatitis involving the scalp, and the armpit and groin creases.
What can happen to children who have infantile atopic dermatitis?
With time the face, especially the cheeks, and flexures become involved.
Young infants cannot scratch and will often rub affected areas, for example the back of the head, causing temporary hair loss.
The backs of the hands can be affected due to sucking. The dermatitis is not necessarily confined to these sites and can be more extensive.
The napkin area is typically spared due to the moisture retention of nappies, although irritant contact napkin dermatitis can still develop.
How does the presentation of acute dermatitis change in toddlers/ school age?
As children grow and develop, the distribution of the dermatitis changes.
With crawling, the extensor aspects of the elbows and wrists, knees and ankles are affected.
The distribution becomes flexural with walking, particularly involving the antecubital and popliteal fossae (elbow and knee creases).
Dribble and food can cause dermatitis around the mouth and chin. Scratching and chronic rubbing can cause the skin to become lichenified (thickened and dry), and around the eyes can lead to eye damage.
During the school years, atopic dermatitis often improves, although the barrier function of the skin is never completely normal
What are some complications of atopic dermatitis especially in school-aged children and adolescents?
- Pityriasis alba
- pomppholyx
- discoid eczema
- pityriasis amiantacea
- lip licker dermatitis
- Atopic dirty neck
What is eczema?
a chronic atopic condition caused by defects in the normal continuity of the skin barrier, leading to inflammation of the skin
What are the 3 diseases of the atopic triad?
1) asthma
2) eczema
3) hay fever
Where does eczema typically present?
over flexor surfaces (inside of elbows and knees) as well as the face and neck
In which anatomical region do adults with new diagnoses of eczema find most inflammation?
hands
Briefly summarise the pathophysiology of eczema:
gaps form in the skin barrier, allowing irritants, microbes and allergens to enter and create an immune response, resulting in inflammation
What clinical presentations are good clues for atopy?
- Keratosis pilaris
- white dermographism
- hyperlinear palms
- Dennie-Morgan folds (Fold of the skin under the lower eyelids due to chronic eyelid dermatitis)
What does a dermoscopy of dermatitis typically show?
a patchy distribution of dotted vessels, focal white scales, and yellow serocrust.
What type of dermatitis is the yellow-clod sign shown in?
Acute exudative dermatitis
What variant is observed in Maori, pacific islander and Africans in association with atopic dermatitis?
Papular variant
What patterns are common in patients of african descent?
Perifollicular and extensor, rather than flexural
