Dermatology: Atopic Dermatitis, Eczema & Psoriasis Flashcards
Define atopic
A form of allergy in which a hypersensitivity reaction (e.g. eczema, asthma) may occur in a part of the body not in contact with the allergen.
What is atopic dermatitis/eczema?
A chronic, atopic, inflammatory skin condition caused by defects in the normal continuity of the skin barrier, leading to inflammation in the skin.
Pathophysiology of eczema?
Defects in the normal continuity of the skin barrier.
Tiny gaps in the skin barrier provide an entrance for irritants, microbes and allergens that create an immune response, resulting in inflammation and the associated symptoms.
Variation in presentation of eczema?
Some patients can have very occasional mild patches that respond well to emollients, where others have large areas of skin that are severely affected and require strong topical steroids or systemic treatments.
Presentation of eczema?
1) itchy, erythematous rash, typically on flexor surfaces (inside of elbows and knees), face, and neck
2) well controlled periods and flares
3) Skin can appear thickened (lichenification) and darker: chronic
Describe location of rash in eczema in:
a) infants
b) younger children
c) older children
a) in infants the face and trunk are often affected
b) in younger children, eczema often occurs on the extensor surfaces
c) in older children, a more typical distribution is seen, with flexor surfaces affected and the creases of the face and neck
What factors can lead to an eczema flare?
1) Environment e.g. it may completely resolve on holiday in warm, humid countries, only to flare on returning to the cold air in the UK.
2) Changes in temp
3) Certain dietary products
4) Washing powders and cleaning products
5) Emotional events or stresses
What is eczema maintenance focued on?
The key to maintenance is to create an artificial barrier over the skin to compensate for the defective skin barrier.
This is done using emollients that are as thick and greasy as tolerated, used as often as possible, particularly after washing and before bed.
What should patients avoid in eczema?
Avoid activities that break down the skin barrier, such as bathing in hot water, scratching or scrubbing their skin and using soaps and body washes that remove the natural oils in the skin.
Avoid itching.
What can be used as soap substitues in eczema?
Emollients or specifically designed soap substitutes
What is the atopic triad?
1) hayfever
2) asthma
3) eczema
What are the 2 types of eczema?
1) Endogenous
2) Exogenous
What are the types of endogenous eczema?
1) Atopic
2) Discord
3) Pompholyx
4) Gravitational
5) Seborrhoeic
What are the 3 types of exogenous eczema?
1) Irritant
2) Allergic
3) Photodermatitis
Prognosis of eczema?
Is a lifelong disease (chronic) but can be controlled with medications. Chronically relapsing.
Management of eczema?
1) Avoid irritants
2) Simple emollients
3) Topical steroids
4) Wet wrapping
5) In severe cases, oral ciclosporin may be used
Presentation of eczema in infants?
Face & trunk
Management of eczema ‘flares’?
1) Thicker emollients
2) Topical steroids
3) Wet wraps
4) Treating any complications such as bacterial or viral infections.
Examples of specialist treatments in eczema?
- zinc impregnated bandages
- topical tacrolimus
- phototherapy
- systemic immunosuppressants e.g. oral corticosteroids, methotrexate and azathioprine.
What is a ‘wet wrap’ in eczema?
covering affected areas in a thick emollient and applying a wrap to keep moisture locked in overnight
General rule with emollients in eczema?
The general rule is to use emollients that are as thick as tolerated and required to maintain the eczema.
Examples of thin emollients for eczema?
E45
Diprobase cream
Oilatum cream
Aveeno cream
Cetraben cream
Epaderm cream
Examples of thick greasy emollients in eczema?
50:50 ointment (50% liquid paraffin)
Hydromol ointment
Diprobase ointment
Cetraben ointment
Epaderm ointment
Diagnosis for eczema requires major and minor criteria. What is the major criteria?
Itchy skin condition (or reports or rubbing/scratching)
Minor criteria in diagnosis of eczema?
o Onset <2 years
o History of skin crease involvement (includes cheeks)
o History of dry skin
o Personal or 1st degree relative history of atopic disease
o Visible flexural dermatitis
Non-medical management of eczema?
Look for potential environmental triggers that may affect symptoms:
o Changes in temperature
o Certain dietary products
o Washing powders
o Cleaning products
o Emotional events or stresses
1st line prevention of flares in eczema?
Emollients e.g. hydromol (topical e.g. creams and ointments, soap substitutes, bath additives)
2nd line prevention of flares in eczema?
1) Topical calcineurin inhibitors (e.g. tacrolimus ointment
2) Pimecrolimus cream (Eidel)
1st line management of eczema flares?
Topical steroids
General rule when using steroids for eczema flare?
Use the weakest steroid cream which controls patient’s symptoms
Give examples of different steroid strengths:
1) Mild
2) Moderate
3) Potent
4) Very potent
1) Hydrocortisone 0.5-2.5%
2) Betamethasone valerate 0.025% (Betnovate RD), Clobetasone butyrate 0.05% (Eumovate)
3) Fluticasone propionate 0.05% (Cutivate), Betamethasone valerate 0.1% (Betnovate)
4) Clobetasol propionate 0.05% (Dermovate)
What class of steroid is dermovate?
Very potent
What class of steroid is hydrocortisone?
Mild
What class of steroid is eumovate?
Moderate
Finger tip rule for topical steroids in eczema?
1 finger tip unit (FTU) = 0.5 g, sufficient to treat a skin area about twice that of the flat of an adult hand
Fingertip units per dose for eczema affected hand and fingers (front and back)?
1.0
Fingertip units per dose for eczema affecting an entire arm and hand?
4.0
Side effects of topical steroids in eczema flare?
- Thinning of skin: may be prone to more flares
- Bruising
- Tearing
- Stretch marks
- Enlarged blood vessels under skin (telangiectasia)
Where should steroids be avoided where possible?
thin skin such as the face, around the eyes and in the genital region
Opportunistic bacterial infection of the skin is common in eczema. The breakdown in the skin’s protective barrier allows an entry point for infective organisms.
What is the most common oragnism causing bacterial infection in eczema?
Staph. aureus
Management of Staph. aureus infection in eczema?
Oral antibiotics, particularly flucloxacillin
If severe –> may require admission and intravenous antibiotics.
Give some complications of eczema
1) Bacterial infections e.g. impetigo (S. aureus)
2) Other infections e.g. hand foot and mouth disease (Coxsachie), molluscum contagiosum
3) Eczema Herpeticum
What is eczema herpeticum?
A viral skin infection in patients (typically with eczema) caused by the herpes simplex virus (HSV) or varicella zoster virus (VSV)
What is the main risk factor for eczema herpeticum?
Eczema
Presentation of eczema herpeticum?
- Rapidly progressing painful rash
- Monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1–3 mm in diameter
- Systemic symptoms e.g. fever, lethargy, irritability and reduced oral intake
- Lymphadenopathy
Management of eczema herpeticum?
Admit for IV aciclovir - life-threatening condition
Most common causative organism of eczema herpeticum?
Herpes simplex virus 1 (HSV-1): may be associated with a coldsore in the patient or a close contact.
What is the most common type of eczema?
Atopic dermatitis
Describe the rash in eczema herpeticum
- usually widespread and can affect any area of the body
- erythematous, painful and sometimes itchy, with vesicles containing pus
- vesicles appear as lots of individual spots containing fluid
- after they burst, they leave small punched-out ulcers with a red base.
Management of eczema herpeticum?
Treatment is with aciclovir. A mild or moderate case may be treated with oral aciclovir, whereas more severe cases may require IV aciclovir.
Complications of eczema herpeticum?
1) When not treated adequately it can be a life threatening condition, particularly in patients that are immunocompromised.
2) Bacterial superinfection can occur, leading to a more severe illness. This needs treatment with antibiotics.
What is irritant contact dermatitis?
Due to superficial damage of the skin surface
Who is irritant contact dermatitis often seen in?
a) linked to occupation e.g. soap
b) mouth of children due to exxcessive licking or dribble (saliva is alkaline)
Cause of irritant contact dermatitis?
- Due to damage of the skin surface by a substance or material, allowing deeper penetration of the irritant
- The extent depends on the irritant and amount/length/frequency of irritant exposure
Presentation of irritant contact dermatitis?
- Usually only present within the area of contact with the irritant
- Red itchy patch, can be well demarcated and dry
- May be swelling and blistering with severe reactions to strong irritants