Atopic dermatitis (Atopic eczema)

Introduction

Atopic dermatitis (also called Atopic Eczema) is an inflammation of the superficial dermis and epidermis, leading to disruption of the skin.
Dermatitis and eczema are used
interchangeably, although eczema was
initially used to refer to blistering dermatitis, being derived from a Greek term meaning ‘to boil over’.
Atopic dermatits is a hereditary disorder
characterised by dry skin, the presence of eczema, and onset less than 2 years.

Epidemiology

A common condition in children; the overall prevalence is rising with a slight male preponderance

Symptoms and clinical features of atopic dermatitis

Atopic dermatitis looks different at different ages and in people of different races.
Essential features are:

  1. Pruritic, exudative, or lichenified eruptions on face, neck, upper trunk, wrists and hands, and in the antecubital and popliteal folds
  2. Personal or family history (in about 70% of cases) of:
    • Allergic manifestations e.g. asthma, hay fever, allergic rhino-conjunctivitis, or eczema
  3. Chronic or chronically relapsing dermatitis
  4. Dry skin

The age at which eczema ceases to be a
problem varies.

  • Many children show a significant improvement by the age of 5 years
  • Most will have only occasional flare-ups by the time they are teenagers.
  • A few continue to have troublesome eczema in adult life, especially those children that suffer from hay fever
  • There is no “cure” for atopic eczema

Differential diagnoses

  • Seborrhoeic dermatitis (especially in the infant)
  • Irritant or allergic contact dermatitis
  • Nummular dermatitis
  • Scabies
  • Psoriasis (especially palmo-plantar)
  • In infants certain immunodeficiency syndromes

Complications of atopic dermatitis

  1. Bacterial infections of the skin
  2. Eczema herpeticum
  3. Complications of over treatment with steroids

Investigations

  • RAST or skin tests may suggest dust mite allergy
  • Eosinophilia and increased serum IgE levels may be present but are nonspecific
  • Blinded food challenges: for diagnosing food allergy

Treatment for atopic dermatitis

Treatment objectives

  • Suppress inflammation
  • Reduce itching
  • Prevent complications

Drug treatment

Topical:
Hydrocortisone 1% or betamethasone valerate 0.1%

  • Apply twice a day until the skin improves then decrease to once a day or less frequently as needed
  • Tacrolimus (0.03% or 1%) apply twice daily

Systemic therapy: Steroids (only to control acute exacerbations)
Prednisolone

  • Adult initially up to 10-20 mg orally daily. Preferably taken as a single dose in the morning after breakfast. In severe disease: up to 60 mg orally daily, as a short course for 5-10 days

Or:

Triamcinolone acetonide 40 mg by deep intramuscular injection, into gluteal
muscle

Criteria for systemic steroid therapy

  • Failed maximal therapy; little improvement after environmental changes
  • Chronic unbearable, unrelenting itch
  • Erythroderma without infections
  • Social setting in which other modalities are impossible

Smallpox vaccination is absolutely contraindicated
Guidelines for the use of potent topical steroids in infants

  1. Do not use on the face, axillae, diaper area or flexures
  2. Do not use under occlusion
  3. Do not use for an area greater than about 25% of total body surface area
  4. Do not use for more than 2 weeks consecutively and do not give refills
  5. Do not dispense more than 50 g per week
  6. Always use sparingly

Adjunctive measures

  1. Exclusive breastfeeding; milk substitute if need be
  2. Attention to cleanliness especially in the diaper region
  3. Avoid excessive bathing, vigorous rubbing, or chafing
  4. Avoid unduly heavy, tight, or soiled clothing
  5. Treat local infections
  6. Pat (rather than rub) skin dry after bath and immediately lubricate skin with petroleum jelly or emulsifying ointment
  7. Showers should be warm to cool, not hot
  8. Tub soaking is good, if followed by adequate lubrication
  9. Avoid wool; its fibers are irritating
  10. Emotional stress leads to increased scratching
  11. In patients and parents of affected children, other psychologic techniques may be useful
  12. Secondary skin infection with bacteria such asĀ  Staphylococcus aureus may worsen the dermatitis and itching
  13. Patients must consciously be shielded from anyone with varicella or herpes simplex
  14. Keep finger nails trimmed short
  15. Some kinds of soap may irritate and dehydrate the skin; use synthetic soap powders
  16. Reassure patients and/or anxious parents
  17. Use patient education handouts
  18. Note: Allergy tests, restriction diets and environmental hypoallergenic changes will not cure eczema

Notable adverse drug reactions

Steroids.

  • Increased susceptibility to and severity of infection
  • Activation or exacerbation of tuberculosis, amoebiasis, strongyloidiasis
  • Risk of severe chickenpox in non-immune patients
  • Nausea, dyspepsia, hiccups
  • Hypersensitivity reactions
  • Atrophy of the skin; striae, telangiectasia, petechiae
  • Glaucoma, cataracts
  • Cushingoid syndrome, adrenal/pituitary suppression, hyperglycaemia and diabetes mellitus
  • Suppression of growth in children
  • Menstrual irregularities
  • Oedema
  • Electrolyte imbalance
  • Hypertension
  • Pseudotumour cerebri