Eczema and Dermatitis Flashcards
Which group is Atopic eczema most common in
Children
Most start in early infancy
What factors contribute to eczema
Genetic and environmental
Often involves mutation in the filaggrin gene, overproduction of cytokines or IgE
More common in Western and industrialised areas
What is the biggest trigger for an eczema breakout
Stress
What conditions is atopic eczema related to and why
Asthma (2+) and hay fever (7+)
Often people with eczema have overreacting Th2 cells that make them sensitive to other triggers
What would be seen under the microscope in skin with eczema/dermatitis
Spongiosis - oedema between keratinocytes
Varying degrees of acanthosis
Inflammatory cell infiltrate - superficial
What are the general signs of eczema/dermatitis
Itch Ill defined rash Erythema Scaling Clustered papulo-vesicles
How do you test for contact dermatitis
Patch testing
Use many patches with the most common allergens
May add extras based on history - e.g. patients own products
Assessed at day 3 and 5
Describe irritant dermatitis
Very common
Non-specific physical irritation rather than an allergy - direct irritation from a substance
e.g. excessive soap/water exposure
May be caused by occupation
How common is atopic eczema
Affects up to 25% of school aged children
What other atopic diseases is eczema associated with
asthma, allergic rhinitis (hayfever), food allergy etc
What is the normal distribution of atopic eczema
Flexural
In crook of elbow, behind knees etc
In infants it is often on their face and extensors!
What are some chronic changes that occur with atopic eczema
Lichenification
Excoriation
Secondary infection
What factors are thought to cause/impact eczema
Multiple genetic and environmental factors
- skin barrier function
- environment
- immunology
Where does photosensitive eczema present
In sun exposed areas
E.g. hands, above collar
What is discoid eczema
The classic eczema erythema and lesions present as well defined circles/ovals
Very itchy
Will be scattered - often on legs
Patients are often atopic
What is stasis eczema
occurs secondary to increased hydrostatic pressure, oedema and red cells being pushied out of vessels
Dry skin forms over varicosed veins
What is the common name for seborrheoic dermatitis in infants
Cradle cap
What is pompholyx eczema
Subtype of eczema
Spongiotic vesicles form - itchy, watery blisters
Skin is itchy with burning sensation, then blisters form. Skin may then dry and peel
Commonly on hands and feet
May be due to irritants
A rash that is never itchy is unlikely to be dermatitis - true or false
True
Dermatitis and eczema are synonymous terms - true or false
True
They both indicate skin inflammation
Describe the acute phase of dermatitis
Fluid accumulation in epidermis - spongiosis
Vesicles and bullae may be seen
Describe the chronic phase of dermatitis
The affected area becomes drier and crustier
Thickened skin with prominent skin markings (lichenification)
What is contact dermatitis
Dermatitis secondary to external agents - exogenous
May be irritant ( non-immune mediated) or allergic.
Which patients are at higher risk of developing contact allergy
Chronic skin conditions (particularly leg ulcers) necessitating prolonged exposure to topical treatments ( under occlusion in some cases)
Certain occupations due to repeated exposure to potential allergens - building trade, hairdressing etc
The majority of contact dermatitis occurs where
On the hands
How do you treat contact dermatitis
Future avoidance of the allergen Symptomatic treatment (emollients, steroids) of the dermatitis as required
How can you differentiate between allergic contact dermatitis and irritant
Irritant reactions tend to be most prominent when the patch is removed, then fade quickly
Allergic reactions often worsen over the course of the patch testing visits
How does irritant dermatitis typically appear
Erythema
Papules
Follicular pustules
What can cause false negatives in patch testing
Insufficient penetration of the potential allergen through the skin - can cause delayed reaction
Too low an allergen concentration
Local or systemic treatment with immunosuppressants (e.g. potent topical steroids, oral steroids, UVB exposure)
What is seborrhoeic dermatitis
Chronic or relapsing form of eczema/dermatitis that mainly affects the sebaceous gland-rich regions of the scalp, face, and trunk
Seen in babies
Describe the appearance of seborrhoeic dermatitis
Ill-defined localised scaly patches or diffuse scale in the scalp - salmon-pink, thin, scaly, and ill-defined plaques
Minimal itch most of the time or not itchy
At what time of year does seborrhoeic dermatitis typically flare up
In winter
Improves in summer following sun exposure
Seborrhoeic eczema in babies can evolve into typical atopic eczema - true or false
True
Can also develop into psoriasis
What are the diagnostic criteria for atopic eczema
Itching plus 3 or more
Visible flexural rash (or cheeks/extensors if an infant)
History of flexural rash
Personal history of atopy (or first degree relative)
Dry skin in past year
Onset before age 2 years
what is the cardinal symptom of atopic eczema
Itching!
Sufferers will often scratch a lot which can make things worse
What are some of the risks of persistent skin scratching
Lichenification Scarring Pigmentary changes Habit scratching Infection
What is the function of filaggrin
It is a protein found in keratohyalin granules in granular layer of epidermis
Helps in terminal differentiation of cells
Mutations in filaggrin genes can lead to which conditions
Mutations cause ichthyosis vulgaris and predispose to atopy
What factors can exacerbate eczema
Scratching Allergens - activate inflammation Diet - in infants Stress Infection Heat/cold Dryness
What food allergies are most commonly linked to eczema in children
Egg & milk commonest
Typically in infants
Majority of eczema not related to food allergy
What type of immune reaction is seen in eczema
Eczema is delayed type IV +/- type 1 reactions
How do you treat eczema
Liberal emollient use - ointments, creams and shower emollients Topical steroids Calcineurin inhibitors Wet wraps and bandages Phototherapy Systemic agents - azith, metho
What are the side effects of topical steroids
Skin thinning Increased skin infections Telangiectasia & Steroid acne Striae - long-term or overuse Minor systemic absorption
How do topical steroids control eczema
Anti-inflammatory
Vasoconstrictive
Antiproliferative
What type of steroid is hydrocortisone
Mild
What type of steroid is betnovate
Potent
What type of steroid is eumovate
moderate
What type of steroid is dermovate
very potent
What is third line topical treatment after emollients then steroids in eczema
Calcineurin inhibitors such as tacrolimus
Used in moderate cases
How are antihistamines used in eczema treatment
Not great evidence but used if sleep disturbance or severe itching
Use sedating AH at night to help sleep
Non-sedating AH for day or school-age
How do you treat infected eczema
Topial fucidin
Consider antiseptics
How does eczema herpeticum present
Monomorphic rash Circular blisters or crusted erosions
May be umbilicated
What is eczema herpeticum
Herpes simplex infection in existing eczema
how do you treat eczema herpeticum
Emergency-needs same day referral
Immediate oral or systemic aciclovir
The majority of eczema cases clear in childhood - true or false
True - for mild/moderate
Continuous reduction with age
