39. Skin rash

Question 1

What is Wiskott Aldrich syndrome?

Answer 1

Eczema + thrombocytopenia + immunodeficiency

• note: may have bloody diarrhoea due to thrombocytopenia

Question 2

Psoriasis.

a) What is it?
b) Risk factors
c) Triggers
d) Clinical features
e) Classifying severity

Answer 2

a) Chronic, relapsing, autoimmune skin disorder

b) - Genetic basis
- Seronegative (HLA-B27) spondyloarthropathies
- IBD

c) - Medication (eg. lithium, BBs, ACE, NSAIDs)
- Stress
- Winter (improves in summer - UV exposure)
- Infection (eg. post-strep guttate flare-up)

d) - Typical rash (usually chronic plaques)
- Psoriatic nail disease
- Psoriatic arthritis
- Other HLA-B27 features (SPINE ACHE)

e) - Body surface are affected: Mild <5%; moderate 5-10% and severe >10%
- Systemic upset (more common in erythrodermic/ pustular)
- Arthritis, nail disease

Question 3

Clinical features of psoriasis lesions

- mnemonic: PSORIASIS

Answer 3

Plaques 
Surfaces - extensor
Oval/circular lesions
Red/pink lesions
Itchy
Auspitz sign
Silvery/white overlying scale
Injury causes lesions (Kobner's phenomenon)
Scalp

Question 4

Psoriatic nail changes: COLD POSS

Answer 4

Crumbling
Onycholysis
Discolouration
Leukonychia

Pitting
Oil drop patches
Subungual hyperkeratosis
Splinter haemorrhages

Question 5

Psoriasis: management

a) 1st line therapies (topical)
b) 2nd line therapies (complex topical/systemic)
c) 3rd line therapies (biologics)
d) When is dermatology referral indicated?

Answer 5

a) Emollients plus topical…
- Potent corticosteroid (eg. beclometasone 0.1%)*
- Vitamin D analogues (eg. calcipotriol)
- Combined steroid/vitamin D (eg. Dovobet)
- Dithranol
- Tar preparations

• note: steroids should only be used short-term (eg. 2 weeks; Dovobet - 4 weeks); also avoid potent steroids on the face

b) - Phototherapy, photochemotherapy, psoralens in combination with UVA irradiation (PUVA)
- Complex topical therapy (Lassar’s paste, crude coal tar)
- Non-biologic systemic drugs: ciclosporin, methotrexate

c) Biologics:
- Anti-TNFs: adalimumab, etanercept and infliximab
- Ustekinumab (IL-12/23 inhibitor)

d) - Severe disease
- >10% body surface area
- Not controlled by topical therapies
- Unsure diagnosis

Question 6

Eczema.

a) Demographics
b) Triggers
c) Common sites
d) Skin lesion features
e) Investigations

Answer 6

a) Most diagnosed < 5 years old; often positive FHx

b) - Irritants - soaps, shampoos, detergents
- Skin infections, especially staph aureus
- Clothing - some fabrics (eg. wool)
- Atopy - inhaled (dust, pet dander, smoke, etc.), food allergy, hayfever
- Stress, pregnancy, pre-menstrual

c) - Flexures
- Baby - face

d) Erythema, dryness, crusting, scaling, cracking, excoriation; chronic scratching - lichenification

e) - Usually not required
- May do IgE specific radioallergosorbant tests (RASTs) to confirm atopy

Question 7

Eczema: diagnostic criteria

Answer 7

ITCHY RASH*, plus 3+ out of:

• Visible flexural eczema (eg. elbow and knee flexures, around the neck (or cheeks if aged < 18 months)
• History of itchy skin creases
• Personal history / family history of asthma or hay fever
• Dry skin
• Onset age < 2
• If no itch, unlikely to be eczema

Question 8

Eczema: secondary bacterial infection

a) Clinical signs
b) Management

Answer 8

a) - Crusting, weeping, pustulation
- Surrounding cellulitis with erythema
- A sudden worsening of the condition

b) - Oral flucloxacillin (erythromycin in pen allergy)
- If not improving, take swabs

Question 9

Eczema herpeticum

a) Clinical signs
b) Management

Answer 9

a) - Areas of rapidly worsening, painful eczema.
- Clustered blisters consistent with cold sores.
- Punched-out erosions
- Possible fever

b) - Admit urgently
- Oral aciclovir (or IV if very unwell)
- Add antibiotic (eg. fluclox) if bacterial infection suspected
- Do NOT use steroids (topical or otherwise)

Question 10

Eczema: 1st line (conservative) management

Answer 10

• Avoid triggers (eg. wool, allergens, irritants)
• Avoid soaps and detergents
• Look out for worsening condition/ signs of infection or herpeticum
• Emollient therapy: use liberally every 4 hours (QDS), 500 g/week for an adult and 250 g/week for a child.

Question 11

Eczema: 2nd line (medical) management

a) What to try first? (strength according to site/severity)
b) Refractory eczema - management
c) Management of lichenification/severe itch

Answer 11

• Continue to use emollients liberally

a) - Mild steroid (eg. hydrocortisone) for mild eczema or for face
- Moderate potency (eg. Betnovate) in moderate eczema
- Potent steroid (eg. beclometasone/ betamethasone) for severe eczema

b) - Specialist assessment
- Possible therapies: phototherapy, systemic steroids, other immunosuppressants (eg. ciclosporin, azathioprine)

c) Bandages containing ichthammol paste