Dermatology

Question 1

Prevalence of atopic eczema

Answer 1

5-15% children, 2-10% adults

Question 2

Infantile atopic eczema key features

Answer 2

Onset <6mnths, persists to 2-3yo. Usu head & neck

Question 3

Childhood atopic eczema key features

Answer 3

Onset in early childhood (2-3yos), persists till puberty. Usu flexures

Question 4

Adult atopic eczema key features

Answer 4

Onset 20-30s. Head, neck, flexures of limbs & trunk. Often PHx infantile or childhood eczema

Question 5

Management of atopic eczema

Answer 5

LIFESTYLE:
- Avoid soaps, detergents, bubble baths, chlorine
- Avoid irritants ie carpet, sand, grass
- Avoid overheating (long hot showers/ baths, tight clothing)
- Soft cotton (avoid wool)
- Regular moisturisers (emollients) ie QV (prevention)
- Don’t scratch, nails short, consider gloves at night
PHARMACOLOGICAL:
- Treat any secondary infection
- Antihistamines at night (usu sedating to improve sleep)
- Topical steroids for flares (mild: hydrocortisone 0.5-1% , mod: betamethasone valerate 0.02-0.05%, severe: betamethasone valerate 0.1%, very severe: betamethasone dipropionate 0.05%) - OINTMENTS rather than creams –> consider modified dressings over top
SEVERE/ TREATMENT RESISTANT:
- Refer to dermatologist
- Phototherapy
- Immunomodulators (methotrexate, ciclosporin, azathioprine)
- Biologics (dupilumab)

Question 6

MACP

Answer 6

Methotrexate, Azathioprine, Ciclosporin, Phototherapy

Question 7

Strength of topical steroids for different locations

Answer 7

Face, genitals, flexures (thin skin) = mild
Trunk, limbs = moderate
Palms, soles, elbows, knees (thick skin) = potent
Nodules, lichenification = very potent

Question 8

Topical steroids SEs

Answer 8

Usu mild & only w prolonged use (SES)
Skin - atrophy (straie, bruising, visible veins), irritation/ stinging, erythema, telangiectasia,
Eyes - glaucoma, cataracts
Systemic - 10% systemically absorbed (does not cause the systemic effects assoc w oral steroids)

Question 9

Atopic eczema complications

Answer 9

• Impetiginisation (secondary bacterial infection)
• Eczema herpeticum
• Erythroderma
• Allergic contact dermatitis

Question 10

Seborrhoeic dermatitis key features

Answer 10

infantile (onset <3mnths, resolving 6-12mnths) or adult (onset adolescence)
Malassezia yeast likely linked

Question 11

Seborrhoeic dermatitis clinical features

Answer 11

Scalp - itchy, diffuse scaling on erythematous b/g
Face - scaly erythema in nasolabial folds, forehead, eyebrows, beard
Chest - lesions often marginated
Flexures - moist, glazed erythema
Blepharitis

Question 12

Seborrhoeic dermatitis management

Answer 12

LIFESTYLE:
- Keratolytics (ie salicylic acid wash)
- Medicated shampoos if scalp involvement (containing ketaconazole or selenium sulfide) - use 2x wkly for 1+ mnths
PHARMACOLOGICAL
- Topical steroids (eg hydrocortisone for 1-3 wks for acute flare)
- Topical antifungals (ie ketaconazole cream daily for 2-4wks)
- Topical tar creams (remove after several hrs)
SEVERE/ TREATMENT RESISTANT
- Oral itraconazole
- Tetracylcine Abx (ie doxy)
- Phototherapy

Question 13

Discoid eczema key features

Answer 13

intensely pruritic, well-demarcated, scattered, nummular (coin-shaped), usu trunk & limbs

Question 14

Discoid eczema management

Answer 14

Treat as a severe form of atopic eczema

- consider intralesional steroid injections if lichenified

Question 15

Pompholyx key features

Answer 15

Episodic form of eczema affecting palms & soles w bulla formation
- vesicles may be extremely itchy (esp lateral sides of fingers & palm)
Cx: paronychia

Question 16

Pompholyx management

Answer 16

LIFESTYLE
- Wet dressing w potassium permanganate (to dry up blisters)
- Emollients (to soothe)
- Cold packs
- Protective gloves
PHARMACOLOGICAL
- Consider short-course of oral prednisolone

Question 17

Pityriasis alba

Answer 17

low-grade eczema, common cause of hypo-pigmentation in children
Epi: ~5% of children
Rf: usu 3-16yo
CFs: areas of hypopigmentation and fine scaling, usu face or upper arms, minimal itch, more obvious following sun exposure
Rx: moisturisers & mild topical steroids

Question 18

Lichen simplex chronicus

Answer 18

Localised area of chronic lichenified eczema. Single or multiple plaques
Cause: constant irritation –> constant itching –> lichenified skin
Rx: potent topical steroids, steroid injections, moisturisers, antihistamines, cooling creams containing methanol, TUC

Question 19

Irritant contact dermatitis

Answer 19

More common than allergic contact dermatitis (80%)
Cause: skin is irritated by friction, environmental factors or chemicals
Main irritants: cold, excess water exposure, alkalis, solvents, adhesives,
RFs: cleaners, hairdressers, food handlers
Rx: protect hands, remove irritant

Question 20

Allergic contact dermatitis

Answer 20

Type 4 (delayed) hypersensitivity reaction
Common allergens: nickel, colophony, rubber additives, chromate, hair dyes
Inx: patch testing
Rx: identify allergen, treat dermatitis (steroids, moisturisers), avoid allergen (may require change of occupation)

Question 21

Patch testing method

Answer 21

On patients back
Allergens placed in Finn chambers
~40 standard allergens tested
Graded by intensity of reaction