Eczema Flashcards
What is eczema ?
Also known as atopic dermatitis
inflammatory skin condition
Commonly affects flexural areas
Multiple types and a spectrum of severity
Wide range of external and internal causes
Which 3 factors are associated with Eczema?
Genetics - affects skin’s barrier function.
Immunology
Environment - temperature, central heating
Definition of atopic eczema
An itchy skin condition in the last 12 months
Plus 3 of the following:
- Onset before age 2
- History of flexural involvement
- History of generally dry skin
- History of other atopic disease or History in 1st degree relative if under 4 yrs (asthma, hayfever, atopic eczema)
What is Spongiosis?
Swelling between cells
within the epidermis
More general definition of eczema
Barrier dysfunction and inflammation
Which gene is key in eczema?
Filaggrin gene
What is Acanthosis?
Thickening of the epidermal layer
Pathology of acute dermatitis
Spongiosis around cells - cells are pushed apart by swelling.
Can lead to accumulation of intra-epidermal vesicles
Infiltration of the epidermis with lymphocytes is common
Pathology of chronic dermatitis
The degree of spongiosis is often mild and difficult to appreciate.
Vesiculation is uncommon. There is significant epidermal acanthosis (thickening of epidermis)
Clinical features of eczema
Itch
Distribution - flexures, neck, eyelids, face, hands + feet
Acute - Pruritus, Erythema, Scale, Papules, Vesicles
Exudate, crusting, excoriation
Chronic - Lichenification, Plaques, Fissuring
What is a very unlikely cause of atopic eczema in children?
Allergy
What are some exogenous types of eczema (3)
Contact dermatitis -Irritant or Allergic
Lichen simplex - response to the skin being repeatedly scratched or rubbed over a long period of time
Photoallergic or photoaggravated eczema
What are some endogenous types of eczema
Atopic Discoid Venous Seborrhoeic dermatitis Pompholyx
Which type of hypersensitivity reaction is allergic contact dermatitis
Type 4
Describe type 4 hypersensitivity reactions. Also how is it tested?
Delayed hypersensitivity – can take 48-72 hrs to develop reaction. T cell mediated
APC’s take allergen to LN and present to naive T cell - Clonal expansion of these T cells released into blood stream
Next encounter of allergen results in Mast cell degranulation, vasodilatation and neutrophils
Tested by a patch test
Describe type 1 hypersensitivity reactions. Also how is it tested?
allergy that causes things like anaphylaxis, bronchospasm, angioedema.
Happens quickly after.
Test by blood tests (IgE antibodies) or skin prick test.
What types of things can cause allergic contact dermatitis?
Toothpaste/make up
Nickel (belt zips, jewelry)
Causes of Irritant contact dermatitis
Friction - micro-trauma, cumulative
Environmental factors - cold, over-exposure to water, chemicals such as acids, alkalis, detergents/solvents
Occupation - Hairdressers, cleaners, NHS staff, nappy rash
What is Patch testing?
Test used to determine whether a specific substance causes allergic inflammation of a patient’s skin.
Potential allergens are applied to the skin
Applied Monday
Remove Wednesday
Re-assess Friday
Seborrhoeic dermatitis (infants)
Common in infants <6 months age usually.
Tends to affect the ears/eyebrows/scalp and proximal flexures.
Often clears within weeks of treatment
Seborrhoeic eczema (adults)
Chronic dermatitis.
Malassezia yeast increased in the scaly epidermis of dandruff and seborrehoic dermatitis (yeast imbalance from childhood)
Dandruff can be a pre-cursor and may gradually progress through redness
Red, sharply marginated lesions covered with greasy looking scales.
Distinctive distribution – areas rich in supply of sebaceous glands (scalp, face, upper trunk).
If you come across a severe case of seborrhoeic eczema which test should you consider
HIV test
How should you treat seborrhoeic eczema
Topical anti-yeast (ketoconazole)
Features of Discoid eczema
Circular plaques of eczema
Cause often unknown
May develop at sites of trauma/irritation
Features of Pompholyx/vesicular eczema
Found on palms and soles
Intensely itchy
More common under 40 years
Sudden onset of groups of vesicles
Resolution can include skin peeling
Features of Asteatotic eczema
Very dry skin - cracked, scaly appearance
Most commonly shins affected
Climate affects it (heat) or excessive washing/soaps
Improved with lots of emollient
Venous eczema
Stasis eczema or varicose eczema
Increased venous pressure
Oedema
Ankle and lower leg involved
Resolution of oedema can help – compression stockings.
Features of Eczema herpeticum
Disseminated viral infection
Fever and often unwell
Itchy clusters of blisters and erosions
Herpes Simplex 1 and 2
Swollen lymph glands
Consider admission!
Antivirals
Treatment of eczema (7)
Patient education
Avoid Causative / exacerbating factors
Emollients (moisturisers)
Ointment – greasy but effective, Creams – lighter, Lotions – more watery
Soap substitutes
Intermittent topical steroids
Sometimes need antihistamines or antimicrobials
Calcineurin Inhibitors - immunosuppression of skin without action of steroids
Which drugs are commonly used in immunosuppression treatment of severe eczema
Azathioprine
Ciclosporin
Mycophenolate mofetil
Methotrexate
Treatment of severe eczema
UV light
Immunosuppression
What was the first biologic used for eczema patients?
Dupilumab
Types of eczema
Asteatotic eczema Seborrhoeic eczema Discoid eczema Pompholyx/vesicular eczema Venous eczema
