Eczema

Question 1

acute eczema

Answer 1

causes a rash with inflammed red skin that is poorly demarcated and less scaly than psoriasis
barrier function of the epidermis is abnormal and the skin is easily irritated
usually itchy with associated excoriations

Question 2

pathophysiology

Answer 2

poorly understood and a number of patterns
endogenous:
atopic, seborrheic, varicose (from venous stasis), discoid

exogenous:
allergic contact (type IV - delayed action via macrophage activation), or irritant contact

different types may coexist

Question 3

atopic eczema

Answer 3

genetic - FH of atopy is common (70%)
infection - staphs colonise legions, suggested by weeping, pustules or crusting
allergens - avoidance can be difficult and of limited benefit

Question 4

diagnosis of atopic eczema

Answer 4

a child must have itchy skin (or parents report scratching) + 3 or more of:

1. onset before 2yrs
2. past flexoral involvement
3. personal Hx of other atopy (or in 1st degree relative if <4yrs)
4. Hx of generally dry skin
5. visible flexural dermatitis (or on cheeks, forehead and outer side of limbs if <4yo)

may be lichenification from constant rubbing or post inflammatory hypo- or hyper-pigmentation

atopic eczema spares the nappy area

Question 5

severity of eczema

Answer 5

mild, moderate, severe based on signs and Sx, and quantity/strength of Tx required
most children grow out of atopic eczema by 13yo

Question 6

explain to patients/families

Answer 6

explain - involves control not cure. advise to report any severe weeping rash eg around the mouth as this may be eczema herpeticum - a primary herpes infection that can be fatal
discourage elimination diets

Question 7

emollients & soap substitutes

Answer 7

dry skin itches and is susceptible to irritants
use emollients liberally (3-4x a day) even when eczema is less active
the best is the one the patients likes the most
intensive use reduces the need for topical steroids

Question 8

topical corticosteroids

Answer 8

use for exacerbations and only on active eczematous skin
apply once a day, 30mins after emollient
steroid-phobia and under-use are common
explain safety if used as prescribed

treat secondary bacterial infection with oral ABx

topical pimecrolimus or tacrolimus can be used if steroids fail to control eczema
systemic treatments such as azathioprine, ciclosporin and methotrexate may be used in severe disease (all immunosuppressant)

Question 9

treating the itch

Answer 9

sedating anti-histamines eg hydroxyzine used intermittently at night can reduce the itch/scratch cycle

Question 10

adult seborrheic dermatitis

Answer 10

common red, scaly rash that affects the scalp, eyebrows, nasolabial folds, cheeks and flexures
caused by overgrowth of skin yeasts
Rx mild topical steroid/antifungal preparations or shampoo
treat intermittently as needed

Question 11

irritant dermatitis

Answer 11

hands often affected
redness +/- weeping often precedes dry fissuring
common irritants:
detergents, soaps, oils, solvents, alkalis, water (if repeated)
often affects bar staff and cleaners
Rx:
avoid all irritants, hand care, PRN use of topical steroids for acute flare ups

Question 12

allergic contact dermatitis

Answer 12

type IV reaction (delayed onset, macrophages)
common allergens:
nickel, chromates, lanolin, rubber, plants topical neomycin etc.
the pattern of contact gives clues to the allergen
often a sharp cut off where the contact ends
secondary spread elsewhere is frequent
Rx: patch testing and avoidance. topical steroids appropriate to severity of reaction