Skin conditions: Eczema and Dermatitis Flashcards
What is the different in pathology of dermatitis and eczema?
Eczema is inflammation of the epidermis whereas dermatitis is inflammation of the dermis. However the conditions exist co-dependently (you do not have one without the other).
How would the skin appear with eczema?
Dry, irritated, inflammed
How does the inflammation present in eczema?
Erythema
Oedema
Oozing
Papules
Crusting
Thickening
Scaling
There is also itching and burning sensation that can occur
What are some of the conditions within eczema?
Atopic dermatitis
Contact dermatitis
Seborrheoic dermatitis
Dyshidrotic dermatitis
There are other types but these are the most common
What is the most common type of eczema?
Atopic dermatitis
How frequently does flare ups occur in atopic dermatitis?
It is characterised by periods of flare ups and remission. A patient may not have any flare ups for long periods of time before re occurring.
Which demographics are most affected by atopic dermatitis?
Atopic dermatitis affects only 1-2% of adults but 15-20% of school children.
Sometimes it can clear up completely in childhood and reoccur in adolescence or present for the first time in adulthood.
Males and females are affected equally.
What percentage of skin problems in GP relate to atopic dermatitis?
30%
What type of hypersensivity reaction is atopic dermatitis?
Type 4 hypersensivity
Eczema is often the first presentation of the atopic triad (alongside asthma and hayfever)
Where does eczema occur on the body?
Flexural areas such as the knees and elbows
In addition to the wrist, neck, face (very commonly the cheeks in young children)
What are some of the causes of atopic dermatitis?
Genetic predisposition - often atopic families. There appears to be a link to a defect in the filaggrin gene which is responsible for maintaining epidermal integrity.
Therefore in these patients there are defects in the skin barrier where it is difficult for the skin to be repaired and maintained and this is linked to a lack of anti-microbial peptides.
Lack of epidermal integrity weakens the epidermal barrier making the patients more susceptible to infection and irritation which allows allergy inducing substances to enter the skin causing inflammation.
How does the location of eczema differ in children and adults?
Children tends to be flexural eczema whereas in adults usually on the hands
What are some of the causes of flare ups?
Heat
Dust
Irritants - smoke
Stress
Foods (in children)
Soaps
Feeling unwell / infection
When does the itching associated with a flare up occur?
Usually at night, can be severe
Aside from dryness, how else do the eczema patches appear?
The dry skin, especially with continued itching can cause the patches to become a red and grey colour (lichenified)
The skin can become raw, sensitive and swollen from this continued scratching
This can lead to skin infections and sores
How are flare ups prevented?
Keeping the skin moist - using moisturisers as this prevents the skin from breaking and allergens entering
Identifying and avoiding possible triggers
Using mild soaps and short showers/baths as the skin getting wet does not help
What are the main treatment options for atopic dermatitis?
Emollients (keeping the skin moist prevents breaks in the skin)
Topical corticosteroids (works locally to reduce inflammation)
Antibiotics if eczema becomes infected
Phototherapy
If the main/topical treatment strategies for atopic dermatitis are ineffective what is used?
First line:
Systemic corticosteroids
Second line:
Topical calcineurin inhibitors - which inhibit the T cell response (preventing production of IL-4)
Other therapies:
Ciclosporin, Azathioprine
Monoclonal antibody Dupilimumab
How does Dupilimumab work?
Dupilimumab is a monoclonal antibody that inhibits IL-4 and IL-13 signalling. IL-4 is produced in response to T-cell activation and causes class switching and secretion of IgE antibodies which then triggers activation of the mast cells to produce inflammatory mediators including IL-13 which recruits more immune cells to the area of inflammation driving the inflammatory response. By blocking both of these signalling pathways this enables skin integrity and barrier function to improve.
When is Alitretinoin used?
As a form of Vitamin A (retinoid) it is used for chronic hand eczema refractory to steroids.
After atopic what is the most common type?
Contact dermatitis
Where is contact dermatitis often seen on the body?
In exposed areas of the body such as the hands, legs, arms or face.
And occurs due to contact with a substance/allergen resulting in stripping of the naturally producing skin oils.