Eczema

• Eczema (Atopic dermatitis)


  Common, chronic, inflammatory skin condition that presents as a poorly demarcated, itchy red rash
• Eczema

  • Typically affects the skin folds, especially in the elbows and behind the knees
  • Can occur almost anywhere on the body in more severe cases
  • Associated with other atopic traits like asthma, hay fever and allergic rhinitis
  • Genetic predisposition and often a family history
  • Most cases present before age 5
  • Affects up to 30% of children and 10% of adults
• Development of eczema

  1. Reduced barrier effectiveness of the skin - dysfunctional filaggrin protein

  2. Exaggerated immune response to allergens that penetrate the skin barrier - IgE mediated response, also known as spongiosis
• The Hygiene hypothesis is used to explain the increasing incidence of eczema and other atopic disorders
• Common triggers for eczema flare-ups

  • Soaps, detergents, shower gels, bubble baths, washing-up liquids
  • Skin infections - particularly staphylococcus aureus
  • Extremes of temperature
  • Abrasive or synthetic fabrics (e.g. wool, nylon)
  • Dietary factors (more important in children)
  • Inhaled allergens like house dust mites, pollen, pet dander, mould
  • Stress
  • Hormonal changes in women
• Clinical features of eczema

  • Rash typically on the flexor surfaces (inside of elbows, wrists, knees), around the eyes, and on the neck
  • Can also involve the scalp and abdomen
  • Pruritus (itch) is the main feature
  • Onset usually within first 3 months of life, but can occur later
  • Infants - rash typically on face, scalp, extensor surfaces
  • Nappy area usually spared
  • Tendency to have generally dry skin throughout life
  • Chronic illness with acute flare-ups

  
• Differential diagnoses

  • Psoriasis
  • Contact dermatitis
  • Seborrhoeic dermatitis
  • Fungal skin infection
  • Lichen simplex chronicus
  • Scabies
• Prognosis of eczema

  • Usually improves throughout childhood, many asymptomatic by age 5
  • Even with apparent regression, symptomatic flare-ups still tend to occur throughout childhood and adolescence
• Complications of eczema

  • Lichenification
  • Staphylococcal infection of lesions
  • Eczema herpeticum (widespread herpes infection)
  • Cataracts
  • Erythrodermic eczema (>90% of body involved)
• Management of eczema

  1. Removal of identified precipitating factors

  2. Use of emollients to improve skin barrier

  3. Use of topical steroids to reduce inflammation

  4. Treatment of secondary staphylococcal infections

  5. Use of immune modulating agents like pimecrolimus and tacrolimus

  6. Phototherapy may be useful
• Differentiating eczema from psoriasis in children can be difficult
• Asteatotic eczema


  "Crazy paving" eczema with fissures and cracks on dry skin, usually on shins of elderly patients
• Lip lickers dermatitis


  Soreness around the mouth due to excess lip licking, treated with emollients
• Risk Factors:

  • Atopic triad - Asthma, Hay fever, Allergic Rhinitis
  • Family history - dysfunction in filaggrin gene
  • Breast feeding - reduces risk
• The NICE (UK) diagnostic criteria suggest diagnosis of eczema requires itchy skin, PLUS three of:

  • Itchiness in the skin folds in front of elbows and back of knees
  • History of asthma or hay fever (one point only even if both are present)
  • Generally dry skin
  • Visible patches of eczema in the skin folds
  • Onset in the first 2 years of life
• Eczema vs Psoriasis:

  Psoriasis may also present similarly, but is usually on the extensor surfaces (outside of the elbows, knees etc). Psoriasis also has a more ‘shiny’ appearance, and there may be fingernail signs. Chronic psoriasis is usually more easy to differentiate due to plaque formation.
• Eczema topical steroids:

  • Mild - Hydrocortisone
  • Moderate - Betamethasone (0.025%), Clobetasone
  • Potent - Betamethasone (0.1%), Fluticasone
  • Very Potent - Clobetasol