Derm - Eczema (Atopic Dermatitis)

Question 1

Definition

Answer 1

Group of skin disorders involving inflammation of the epidermis. Typically episodic disease of flares + remissions.

Question 2

Types of eczema

Answer 2

Atopic dermatitis (MC) - seen in children with Hx of atopy e.g asthma
Contact dermatitis - due to exposure to irritants or allergens
Dyshidrotic eczema - blistering lesions on hand and feet
Discoid eczema - coin shaped eczematous lesions
Seborrheic dermatitis - an inflammatory reaction to Malassezia furfur
Venous dermatitis - venous insufficiency leads to stasis and subsequent inflammation

Question 3

Epidemiology

Answer 3

Childhood manifestation (70% by 4 yrs)
Developed world
Urban areas
Atopy e.g. asthma and allergic rhinitis
Family history
Triggers: irritants (soap, detergent), cold, dampness, dust, mites, pollen

Question 4

Pathophysiology

Answer 4

Defects in the epidermal barrier, allow for sensitisation against allergens. An immune response is subsequently triggered following sensitisation, leading to IgE production and eosinophilia. The result is itchy, dry patches of skin.

Question 5

Signs

Answer 5

Erythema
Vesicles and pustules: assosciated with acute flares
Lichenification: occurs due to scratching and suggests chronic disease
Excoriations

Question 6

Symptoms

Answer 6

Pruitus
Dry skin
Infants: face and extensor surfaces commonly affected by
Children and adults: flexural surfaces commonly affected

Question 7

Diagnosis

Answer 7

Clinical diagnosis - no investigations needed unless the diagnosis is unclear

Investigations to consider:
- Allergy testing: useful in children with Hx of atopy in order to identify particular allergens to prevent exacerbations of eczema

Question 8

Treatment

Answer 8

Mild = dry skin with frequent itching
- Emollients: advise to use liberally
- Mild corticosteroids: 1% hydrocortisone can be used in areas of redness

Moderate = dry skin, redness, and frequent itching
- Emollients: advised to use liberally
- Moderate corticosteroids: betamethasone valerate 0.025% or clobetasone butyrate 0.05% used on inflamed skin. Consider milder potency steroids on delicate areas, such as the face.
- Antihistamine: may help with pruritus

Severe = widespread dry skin, redness and incessant itching. Excoriation, oozing and bleeding may be present
- Emollients: advised to use liberally
- Potent corticosteroid: betamethasone valerate 0.1% with milder potency steroids for delicate areas
- Oral corticosteroid: indicated if extensive disease with psychological distress
- Antihistamine: may help with pruritus

Question 9

Secondary care treatments

Answer 9

Topical tacrolimus
Ultraviolet (UV) therapy
Systemic immunosupression e.g. Azathioprine, methotrexate, ciclosporin

Question 10

Complications

Answer 10

Eczema herpeticum: a severe-life threatening skin infection caused by herpes simplex virus (HSV), infection, requiring hospital admission and IV aciclovir therapy
Bacterial infection: characterised by weeping, redness, crusting, vesicles and pustules, requiring topical or oral Abx

Question 11

Steroid ladder (weakest to most potent)

Answer 11

Mild: Hydrocortisone 0.5%, 1%, and 2.5%
Moderate: Eumovate (Clobetasone butyrate 0.05%)
Potent: Betnovate (betamethasone 0.1%)
Very Potent: Dermovate (clobetasol propionate 0.05%)