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
Management of irritant contact dermatitis?
- Avoidance of irritant
- Emollients
- Topical steroids
What are the 2 main types of contact dermatitis?
1) Irritant contact
2) Allergic contact
What is allergic contact dermatitis?
Type IV hypersensitivity reaction.
Due to a substance or material in contact with the skin causing an allergic reaction.
Allergen MUST usually have contact with skin
Where is allergic contact dermatitis often seen in?
Often seen on the head following hair dyes: an acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself.
What is a frequent cause of both irritant and allergic contact dermatitis?
Cement
What are common allergens in allergic contact dermatitis?
nickel, perfumed substances, hair dye (paraphenylene diamine), plasters (rosin), plants, cement
How is allergic contact dermatitis confirmed?
Patch test
Presentation of allergic contact dermatitis?
- Usually only affects the area which had direct contact with the allergen but may spread
- Often red & itchy but can become swollen and develop blisters & fissures
Management of allergic contact dermatitis?
It may resolve on its own as long as the allergen is removed
- Identify the allergen and take avoidant measures
- Emollients
- Topical steroids
Who is seborrhoeic dermatitis most common in?
1) young adults
2) elderly
3) males
What is infantile seborrhoeic dermatitis also known as?
Cradle cap
Seborrhoeic dermatitis is a relatively common skin disorder seen in children.
Where does it affect?
1) scalp (cradle cap)
2) nappy area
3) face
4) limb flexures
Describe cradle cap
Cradle cap is an early sign which may develop in the first few weeks of life. It is characterised by an erythematous rash with coarse yellow scales.
What is a mild form of seborrhoeic dermatitis?
Dandruff
Cause of seborrhoeic dermatitis?
Due to an overgrowth of the yeast Malassezia
Risk factors for seborrhoeic dermatitis?
- Oily skin
- FH
- Psoriasis
- FH of psoriasis
- Immunosuppression
Management of cradle cap in infants?
1) reassurance that it doesn’t affect the baby and usually resolves within a few weeks
2) massage a topical emollient onto the scalp to loosen scales, brush gently with a soft brush and wash off with shampoo.
3) if severe/persistent a topical imidazole cream may be tried
When does seborrhoeic dermatitis tend to resolve in children?
Seborrhoeic dermatitis in children tends to resolve spontaneously by around 8 months of age.
Features of seborrhoeic dermatitis in adults?
1) eczematous lesions on the sebum-rich areas: scalp (may cause dandruff), periorbital, auricular and nasolabial folds
2) otitis externa and blepharitis may develop
3) not itchy
4) flares worse in winter and improve with sun exposure
What 2 conditions are associated with seborrhoeic dermatitis in adults?
1) HIV
2) Parkinson’s disease
1st line management of scalp disease in seborrhoeic dermatitis in adults?
ketoconazole 2% shampoo
Other management options in seborrhoeic dermatitis in adults?
1) Keratolytics to remove scale
2) Topical corticosteroids
3) Topical calcineurin inhibitors
4) Medicated shampoo
What is stasis dermatitis?
Also known as venous eczema. Often affects lower legs of elderly patients.
Who is often affected by stasis dermatitis?
lower legs of elderly patients.
Cause of stasis dermatitis?
Venous insufficiency – results in fluid pooling in the tissues of the leg, activating an immune response and leading to inflammation
Risk factors for stasis dermatitis?
o DVT
o Cellulitis
o Chronic leg swelling
o Varicose veins
o Venous leg ulcers
1st line management of face and body disease in seborrhoeic dermatitis?
topical antifungals: e.g. ketoconazole
topical steroids: best used for short periods
difficult to treat - recurrences are common
Clinical features of stasis dermatitis?
1) Patches/plaques can be itchy, red and blistered or dry and scaly
2) Haemosiderin staining – deposition causes a brown discolouration
3) Atrophie blanche
4) Lipodermatosclerosis
5) 2ary infection can occur leading to cellulitis (S. pyogenes)
What is haemosiderin?
An iron storage complex that is produced from the breakdown of haem
What causes haemosiderin staining in stasis dermatitis?
Staining is caused by blood leaking out of vessels and haem is broken down e.g. in venous insufficiency
What is atrophie blanche?
white patches of thin and scarred skin
What is lipodermatosclerosis?
skin thickening - this leads to ‘champagne bottle’ lower leg shape
Which organism often causes 2ary infection in stasis dermatitis?
Strep. pyogenes
Management of stasis dermatitis?
1) Reduce leg swelling:
- Regularly move the legs (e.g. walking)
- Elevate the legs when seated and overnight
- Bandaging
- Compression stockings
2) Antibiotics for 2ary infection
3) Topical steroid
4) Emollient or moisturize
5) Doppler pre compression
What is asteatotic dermatitis?
Most common cause?
Due to dry skin, commonly occurs on lower legs due to excess washing.
Who is asteatotic dermatitis more common in?
Elderly
Clinical features of asteatotic dermatitis?
Crazy-paving appearance with white patches and red lines.
Treatment of asteatotic dermatitis?
1) Remove factors that may have excessively dried in the skin e.g. reduce bathing frequency, replace soaps, reduce ambient temperatures
2) Emollients and moisturizers
3) Mild topical steroid
What is psoriasis?
A chronic, autoimmune, inflammatory skin condition that causes recurrent symptoms of psoriatic skin lesions.
Who is psoriasis more common among?
- Men and women are equally affected.
- Commonest among Caucasian patients
- Bimodal peaks of onset at approximately 15-25 and 50-60 y/o
It is now recognised that patients with psoriasis are at increased risk of what 2 other conditions?
1) arthritis
2) CVS disease
Concordance of psoriasis in identical twins?
Strong - 70%
What genes are implicated in psoriasis?
1) HLA-Cw6
2) HLA-B13
3) HLA-B17
Pathophysiology in psoriasis?
T cells are inappropriately induced to produce cytokines that stimulate inflammatory cell infiltration (leading to erythema) and keratinocyte proliferation (leading to scale as the stratum corneum is shed from the skin).
Skin changes caused by rapid regeneration of new skin cells – resulting in an abnormal buildup and thickening of skin in those areas
What may psoriasis be a) worsened by, b) triggered by, c) improved by?
a) skin trauma, stress
b) Strep. infection
c) sunlight
What are the 4 subtypes of psoriasis?
1) plaque psoriasis
2) flexural psoriasis
3) guttate psoriasis
4) pustular psoriasis
What is the most common form of psoriasis?
plaque psoriasis
Features of plaque psoriasis?
Typical well-demarcated red, scaly patches affecting the extensor surfaces, sacrum and scalp.
Histological findings in psoriasis?
1) Thick epidermis (acanthosis) with a saw-toothed appearance
2) Papillary dermis very close to surface
3) Vascular proliferation (Auspitz sign)
What type of psoriasis is associated with streptococcal infection?
Guttate psoriasis
Give some precipitating factors for psoriasis
- Infections – streptococcal (associated with guttate psoriasis)
- Hormonal changes – e.g. postpartum
- Initiation, withdrawal or change in dose of some medications e.g. lithium, chloroquine and derivatives, and steroids (systemic & potent topical forms)
Give some exacerbating factors for psoriasis
- Trauma e.g. cuts, abrasions or sunburn – may precipitate spread of plaques to unaffected areas (Koebner phenomenon)
- Smoking
- Alcohol
- Some medications e.g. beta blockers
- Psychological stress
What is Koebner phenomenon?
the appearance of new skin lesions on previously unaffected skin secondary to trauma e.g. psoriasis, vitiligo, lichen planus
Give some relieving factors for psoriasis
- Sunlight – symptoms tend to worsen in winter and improve in summer
HOWEVER sunlight can be an exacerbating factor in 10% patients
What is Auspitz sign?
Gentle scraping and removal of scale causes pinpoint capillary bleeding (not specific or sensitive test).
Give 2 other features of psoriasis (affecting other parts of body)?
1) nail signs (50%): pitting, onycholysis
2) arthritis (5-10%): patient may complain of joint pain and stiffness
What nail signs may be seen in psoriasis?
- pitting
- onycholysis
What is onycholysis?
Onycholysis is when your nail separates from its nail bed.
Describe psoriatic lesions in chronic plaque psoriasis
1) Red (erythematous), scaly plaques (areas of thickened skin)
2) Well-demarcated
3) Disease on scalp, elbows and knees (extensor surfaces)
4) Potential involvement of whole skin
5) Overlying scale except for on flexural surfaces (skin folds) where plaques appear shiny and moist
Features of guttate psoriasis?
Multiple small, scaly plaques distributed across the trunk and limbs which may resemble raindrops
What does guttate psoriasis often acutely follow?
Strep infection –> ask about sore throat
What should you always ask about in psoriasis history?
Sore throat?
Flexural psoriasis vs plaque psoriasis?
flexural psoriasis: occurs on flexor surfaces, in contrast to plaque psoriasis the skin is smooth
Where does pustular psoriasis often occur?
commonly occurs on the palms and soles
What is erythrodermic psoriasis ?
Rare but severe form can lead to widespread inflammation (significant fluid loss, dehydration, electrolyte abnormalities etc)
Associated conditions in psoriasis?
1) Psoriatic arthritis: rash typically precedes arthropathy
2) IBD: psoriasis can be a cutaneous manifestation of IBD
3) Uveitis: inflammation of mid portion of eye
4) Nail psoriasis: pitting, thickening, discolouration, onycholysis
5) Metabolic syndrome: abdominal obesity, hypertension & insulin resistance
6) Poor mental health: depression & anxiety
7) CVS disease & VTE
Lifestyle factors in psoriasis?
- Avoiding exacerbating factors
- Smoking cessation
- Reducing alcohol
- Maintaining healthy weight
NICE recommend a step-wise approach for chronic plaque psoriasis.
1st line?
1st line: potent corticosteroid applied once daily plus vitamin D analogue applied once daily.
N.B. regular emollients may help to reduce scale loss and reduce pruritus
How should potent corticosteroid be applied in chronic plaque psoriasis?
Should be applied separately, one in the morning and the other in the evening)
for up to 4 weeks as initial treatment, for up to 4 weeks as initial treatment
2nd line management of psoriasis (i.e. if no improvement after 8 weeks on corticosteroid)?
a vitamin D analogue twice daily
3rd line management of psoriasis?
offer either:
1) a potent corticosteroid applied twice daily for up to 4 weeks, or
2) a coal tar preparation applied once or twice daily
What is another 2ary care treatment option in psoriasis?
Phototherapy –> narrowband ultraviolet B light is now the treatment of choice.
Adverse effects of phototherapy in psoriasis?
Skin ageing, squamous cell cancer (not melanoma)
If extensive psorasis cannot be controlled with topical therapy AND is having significant impact on physical/psychological or social wellbeing, systemic therapy can be used.
What are some options?
1) Methotrexate (1st line)
2) Ciclosporin
3) Acitretin
1st line systemic therapy option in psoriasis?
Methotrexate
Contraindications of methotrexate?
Pregnancy, breastfeeding, severe hepatic impairment, bone marrow depression, severe renal impairment
Give some examples of vitamin D analogues
calcipotriol (Dovonex), calcitriol and tacalcitol
Can vitamin D analogues be used lonterm?
Yes (unlike corticosteroids)
Vitamin D analogues in pregnancy?
Avoid
What drugs may exacerbate psoriasis?
beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
What is guttate psoriasis typically preceded by?
a streptococcal sore throat 2-4 weeks
Main differential of guttate psoriasis?
Pityriasis rosea
Treatment of guttate psoriasis?
Most cases resolve spontaneously within 2-3 months
Topical agents as per psoriasis
UVB phototherapy
