Eczema (Atopic Dermatitis) Flashcards
Who gets atopic dermatitis aka eczema?
- 30% of children (babies on cheeks and scalp), flexor surfaces
- 10% of adults
- atopic triad: eczema, asthma, allergic rhinitis (hay fever). Hx in 70%
- incidence highest in developed countries and urbanised areas
- FHx
- breast feeding for 3 months decreases risk
(contact dermatitis is caused by contact with irritants; varicose eczema is from venous stasis)
What is the understood pathophysiology of eczema?
- REDUCED BARRIER EFFECTIVENESS
- genetic tendency to ineffective barrier (FILAGGRIN) allows everyday environmental allergens in.
- reduced quantity or poor quality filaggrin in barrier.
- emollients help improve barrier - IMMUNE RESPONSE
- exaggerated immune response to chemicals/allergens
- inflammation is called SPONGIOSIS
- hygiene hypothesis less exposure = pro-allergic T-cells.
- steroids help reduce the inflammation
Common triggers:
- soaps, detergents, shower gels, bubble baths
- Staph aureus skin infection
- extremes of temp
- dietary could be factor in children
- inhaled (dust mites, pollen, pet dander, mould)
- stress
- hormonal (pregnancy, flares in menstrual cycle)
Clinical features of eczema?
- flexor surface rash
- itch (pruritus) is main feature
- weep, scaling, crust, colour change
- onset normally at 3 months old but can be later (infant its face, scalp and extensors)
- dry skin throughout life
- chronic illness with flare ups
- bacterial infection is a common complication (crusting, weeping and red)
- eczema herpeticum (co-existing with HSV, very rapid onset, eczema patches with concurrent herptic-type blisters, painful, punched out lesions of 1-3mm diameter, fevers, lethargy)
Eczema diagnosis?
Investigations?
Diagnosis is clinical.
Good history to distinguish contact vs atopic.
NICE: Itchy skin plus three of: - itchiness in folds of elbows / knees - Hx of asthma or hay fever - generally dry skin - visible patches of eczema in skin folds - onset in the first 2 years of life
Investigations:
Not necessary.
MC+S swabs if infected and not responding to treatment.
Differential diagnoses when thinking atopic eczema?
- psoriasis
- contact dermatitis
- seborrheoic dermatitis
- fungal skin infection
- lichen simplex chronicus
- scabies
Prognosis and complications of eczema?
Prognosis:
- usually improves throughout childhood, many are asymptomatic by 5yo
- even so, there will be flare ups through childhood and adolescence
Complications:
LICHENIFICATION; thickened and leathery skin due to epidermal hypertrophy
STAPHYLOCOCCAL infection of lesions
ECZEMA HERPETICUM;
- vesicular lesions, can be anywhere but usually at a flare site
- may become ill with lymphadenopathy 5 days after vesicle appear
- can be infected with staphylococci
- rarely viraemia which can be fatal
CATARACTS; risk in those with longterm disease, can be a feature of the disease or from steroid use. Dont prescribe steroids for eczema near the eyes.
ERYTHRODERMIC ECZEMA; eczema involving >90% of the body
Principles of management of eczema?
- Removal of precipitating factors - soaps, wool, temp extremes, dust mite faeces
- Emollients - creams, lotions, ointments
- Steroids - apply before emollients, varying potency
- Treat staphylococcal infection - oral FLUCLOXACILLIN 500mg QID for 1-2weeks
- Immune modulating agents
- Phototherapy - sunlight may help, avoid in children, can cause sun damage.
- Systemic therapy - very rarely systemic steroids may be used
Advice on emollients for eczema?
Creams are water based and more pleasant but least effective.
Lotions have both oil and water.
Ointments are oil based and most potent but least tolerated.
Use liberally and regularly, >500ml/week, every 4 hours or at least 3-4 times a day.
Shower emollients can replace drying shower soaps.
what are some different steroid options?
(hydro, eu, bet, derm)
Mild:
eg 1% hydrocortisone, 0.05% clobetasone (EUMOVATE more potent than hydrocortisone)
Face for <5 days (not near eyes)
Rest of body <2weeks
Moderate
eg betamethasone valerate 0.02%, triamcinolone 0.02%
Potent
eg BETNOVATE, 0.1% betamethosone validate, mometasone 1%, methyprednisolone acetylate
Very potent:
eg clobetasone propionate 0.05% (DERMOVATE very potent), betamethasone diproprionate 0.05%
NOT for face!
For persistent rash and lichenification.
Others
Haelan tape - fludroxycortide, useful for fingers and healing fissure
Side effects
- skin thinning
- striae formation
- telangiectasia
- adrenal suppression, cushings syndrome is rare
What immune modulating agents could be used in eczema?
PIMECROLIMUS and TACROLIMUS, T-cell suppressants, topical or oral for moderate to severe eczema. Local stinging but this subsides after a few days.
BARICITINIB - JAK inhibitor recently licensed.
Differentiating psoriasis from Eczema? (esp in kids)
- difficult in children
- location and plaques are more straightforward in adults
In children:
- if umbilicus is involved, probably psoriasis
- psoriasis plaques tend to be thicker and often found on face and scalp
- treatment is similar with tar and topical vit D added in psoriasis
What is “crazy paving” eczema called?
ASTEATOTIC eczema
(aka eczema craquelé)
- fissures and cracks on dry skin
- usually occurs on shins, typically in elderly patients
- result of dehydration of the epidermis
- more common in winter
- MOISTURISING should resolve it
What is lip lickers dermatitis?
Is a reaction of the lips (ECZEMATOUS CHEILITIS) and surrounding skin (irritant contact dermatitis) from contact with irritating saliva.
- soreness around the mouth due to excess lip licking
Use emollient like VASELINE
What are the different types of eczema?
Exogenous:
- Photosensitive
- Allergic Contact Dermatitis
- Irritant contact Dermatitis
Endogenous:
- Atopic eczema
- Seborrhoeic eczema (often fungus contributes)
- Venous eczema
- Asteatotic eczema
