Eczema Flashcards
How common is eczema?
24% of children will be diagnosed with eczema at some point in their childhood
Prevalence is rising
Rates of hospital admission for children and adults is increasing
What is eczema also known as?
Atopic dermatitis
What is eczema?
A common INFLAMMATORY skin condition.
Commonly affects FLEXURAL areas.
Multiple types and a spectrum of severity
Wide range of external (exogenous) or internal (endogenous) factors can induce the condition
What is the epidemiology of eczema?
Overall prevalence is 4% in Western countries
Most commonly appears in babies and children
-By adult life 60% have cleared
Recent studies indicated rising numbers
- More so in”developed” regions
- Social class effect?
- Commoner in cooler climates?
- Pollution? Other environmental factors?
What is the 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
- –History in 1st degree relative if under 4 yrs
How are genetics involved in the pathogenesis of atopic eczema?
Many genes implicated
Key role for Filaggrin gene
Atopic family history
-May develop any or all of three closely linked conditions; atopic eczema, asthma and hay fever (allergic rhinitis)
What factors are involved in pathogenesis of atopic eczema?
Genetics
Epidermal Barrier dysfunction
Environmental factors
Explain the histology of atopic eczema
Spongiosis within the epidermis
Acanthosis
Inflammation - superficial perivascular lymphohistiocytic infiltrate
What is spongiosis?
Spongiosis is mainly intercellular edema (abnormal accumulation of fluid) in the epidermis, and is characteristic of eczematous dermatitis, manifested clinically by intraepidermal vesicles (fluid-containing spaces), “juicy” papules, and/or lichenification.
What is acanthosis?
Acanthosis is diffuse epidermal hyperplasia (thickening of the skin). It implies increased thickness of the Malpighian layer (stratum basale and stratum spinosum)
What are the clinical features of atopic eczema?
ITCH
Distribution
- Flexures, Neck, Eyelids, Face, Hands and feet
- Tends to spare nappy area
Acute changes
- Pruritus, Erythema, Scale, Papules, Vesicles
- Exuate, crusting, excoriation
Chronic changes
-Lichenification, Plaques, Fissuring
What is excoriation?
A scratch or abrasion to the skin
What is lichenification?
Thick, leathery skin, usually the result of constant scratching and rubbing.
With prolonged rubbing or scratching, the outer layer of the skin (the epidermis) becomes hypertrophied (overgrown) and this results in thickening of the skin and exaggeration of the normal skin markings, giving the skin a leathery bark-like appearance.
What are the types of endogenous eczema?
- Atopic
- Discoid
- Venous
- Seborrhoeic dermatitis
- Pompholyx
- Juvenile plantar dermatitis
What are the types of exogenous eczema?
Contact dermatitis
- Irritant
- Allergic
Lichen simplex
Photoallergic contact dermatitis
What is the pathogenesis of allergic contact dermatitis?
Type 4 Hypersensitivity
-Delayed hypersensitivity (can take 48-72hrs to develop reaction)
Antigen presenting cells tale happen/ allergen to LN and present to niave T cells
Clonal expansion of these T cells, released into blood stream
When these T cells next encounter hapten
-Mast cell degranulation, vasodilation and neutrophils
How does patch testing work?
Potential allergens applied (NO needles involved)
Baseline/standard series - applied to all patients
Applied Monday
Remove Wednesday
Re-assess friday
What is irritant contact dermatitis?
Form of contact dermatitis in which the skin injured by…
FRICTION
- Microtrauma
- Cumulative
ENVIRONMENTAL FACTORS
- Cold
- Over exposure to water
- Chemicals such as acids, alkalis, detergents and solvents
What occupations are at risk of contact dermatitis?
Hairdressers
NHS staff
Cleaners
Dermatitis -> under a ring on finger -> soaps can accumulate -> irritant
Nappy rash
What is seborrhoeic dermatitis?
Seborrheic dermatitis is an inflammatory skin disorder affecting the scalp, face, torso and proximal flexures.
Typically, seborrheic dermatitis presents with scaly, flaky, itchy, and red skin.
It particularly affects the sebaceous-gland-rich areas of skin.
Describe seborrhoeic eczema in adults
In adolescents and adults, seborrhoeic dermatitis usually presents as scalp scaling similar to dandruff or as mild to marked erythema of the nasolabial fold.
Red, sharply marginated lesions covered with greasy looking scales
How do you treat seborrhoeic eczema?
Malassezia yeast increased in the scaly epidermis of dandruff and seborrheoic dermatitis.
Treat with topical anti-yeast (ketoconazole)
What is discoid eczema?
Circular plaques of eczema
Cause often unknown
May develop at sites of trauma/ irritation
What is pompholyx/ vesicular eczema?
Palms and soles
Intensely itchy
More common in under 40s
Sudden onset of crops of vesicles
Resolution can include desquamation
What is asteatotic eczema?
Very dry skin
Cracked scaly appearance
Most commonly shins affected
Climate- heat
Excessive washing/soaps
What is venous eczema?
Stasis eczema or varicose eczema
Increased venous pressure
Oedema
Ankle and lower leg involved
Resolution of oedema can help -> compression stockings
What is eczema herpeticum?
Disseminated viral infection
Fever and often unwell
Itchy clusters of blisters and erosions
Herpes Simplex 1 and 2
Swollen lymph glands
What should you consider in eczema herpeticum?
Consider admission
Antivirals
Consider secondary bacterial infection
How do you treat eczema?
- Patient education
- Avoid causative/ exacerbating factors
Emollients (moisturisers)
Soap substitutes
Sedating antihistamines (if needed)
Intermittent topical steroids
Antimicrobials
Calcineurin inhibitors
-Topical pimecrolimus and tacrolimus
UV light
Immunosuppression
What types of emollients can you consider giving?
- Ointment (greasy but effective)
- Creams (lighter)
- Lotions (more watery)
What different intermittant topical steroids can you consider giving?
Different potency
- Hydrocortisone (low)
- Betamethasone (potent)
What immunosuppression can you consider giving?
Azathioprine
Ciclosporin
Mycophenolate mofetil
Methotrexate
What are the benefits of topical steroids?
Fast and effective short-term treatment
What are the potential cutaneous risks of topical steroids?
Skin atrophy/ striae
Telangiectasia, pigmentation abnormalities
Acneform, rosacea-like eruptions
Glaucoma
What are the potential systemic risks from topical steroids?
Growth retardation
Cushing’s syndrome
