Eczema

Eczema - Pathophysiology and Therapies
Eczema Definition

  • Eczema: A condition characterized by inflammation of the skin.

Types of Eczema

  1. Atopic Eczema

    • A chronic disease leading to inflammation, redness, and irritation of the skin.

  2. Seborrhoeic Eczema

    • Typically affects the scalp.

  3. Contact Eczema

    • Irritant Contact Eczema

    • Allergic Contact Eczema

  4. Nummular Eczema / Discoid Eczema

    • A long-term skin condition that results in itchy, swollen, and cracked skin.

  5. Pompholyx

    • Characterized by tiny blisters on the fingers, palms, and sometimes the soles of the feet.

  6. Nappy Rash

Presentation of Eczema

  • Chronic Nature: Usually episodic, characterized by redness and itching.

  • Epidemiology:

    • Affects 1 in 5 children and 1 in 12 adults, with most cases presenting between 3 months and 5 years of age.

  • Common Symptoms:

    • Itchy skin

    • Red, dry patches

    • Over time, skin can become thickened or 'lichenified' (thickened and leathery).

    • During acute flares, skin can become blistered, weepy, or infected.

Changes with Age in Eczema Presentation

  • Infants: Presentation most commonly on cheeks.

  • Children: Presentation on skin creases.

  • Adults: Presentation varies with age.

Causes of Eczema

  • Impaired Skin Barrier: Leading to water loss which causes dry skin.

  • Genetic Predisposition:

    • Family history of atopy increases risk; 8/10 children affected if both parents have a history.

    • 6/10 children affected if one parent is affected.

    • Filaggrin gene mutation: Found in approximately 50% of patients.

  • Environmental Factors:

    • Evidence suggests an inverse relationship with endotoxin exposure, early daycare, number of siblings, farm animals, and pet dogs.

    • Notably, eczema is not caused by food allergy, although severe cases may coexist with food allergies that aggravate skin conditions.

Diagnosis of Eczema

  • Diagnosis criteria require at least three of the following features:

    • A history of itchy rash commonly affecting cheeks in children under 4 years.

    • Rash on skin creases (e.g., elbow, knees) in older children and adults.

    • History of asthma or hay fever; family history in first-degree relatives for children under 4.

    • Generalized dry skin in the past year.

    • Visible eczema.

    • Onset in the first two years of life.

Triggers of Eczema

  • Irritants:

    • Soaps and detergents, shampoos, bubble baths, etc.

  • Skin Infections

  • Contact Allergens

  • Food Allergens

  • Inhalant Allergens

Treatment of Eczema

1. Everyday Care

  • Avoid Irritants and Triggers:

    • Washing: Avoid soaps, use soap substitutes, and add emollients to bath water.

    • Avoid hot water and pat skin dry after washing.

    • Prevention of Scratching: Keep nails short; use cotton clothes and mittens for infants.

    • Avoid Extreme Heat: Choose appropriate clothing.

2. Emollients

  • Usage: Essential part of daily care, even when skin is clear.

  • Formulations: Available OTC (over-the-counter), some covered on medical cards.

  • Application: Liberal and frequent application advised; cannot be overused as they do not absorb.

  • Options: Includes Silcock

3. Steroid Treatment

  • Used during flares or as maintenance treatment in severe cases.

  • Types include mild, moderate, potent, and very potent topical steroid preparations:

    • Cream for weeping areas

    • Ointment for dry areas

    • Lotion for hairy areas.

Steroid Usage Guidelines

  • Fingertip Unit (FTU): Amount of cream from the tube to the end of an adult's finger.

    • One FTU can cover an area the size of double the flat of an adult's hand.

    • 1 FTU = approximately 0.50.5g of cream.

4. When to Refer

  • Cases requiring more treatment than general care or mild steroids.

  • Eczema not responding to treatment, including suspicion of infection (e.g., bacterial).

  • Moderate to severe eczema cases or when hydrocortisone treatment is not appropriate (e.g., under 12 years).

5. Other Prescription Treatments

  • Oral Antihistamines: Not routinely recommended.

  • Tacrolimus Ointment: Topical immunomodulator for moderate to severe eczema in those over 2 years.

  • Specialist Treatments: Wet wraps, occlusive bandages, light therapy, immunosuppressive medications (methotrexate, ciclosporin), biological agents (e.g., Dupilumab).

Special Types of Eczema

Seborrhoeic Eczema

  • Infantile Form: Known as 'cradle cap,' most common in infants.

  • Adult Form: Gentle scaling rash, affecting up to 5% of the population; commonly triggered by fatigue, stress, or cold weather.

Contact Eczema

  1. Irritant Contact Eczema

    • Most common type, localized to the area in contact with irritant (e.g., detergents).

  2. Allergic Contact Eczema

    • Resulting from specific allergens after sensitization and re-exposure.

Presentation & Assessment of Contact Eczema

  • Common features include redness, itching, blistering, and chronic exposure may result in fissures or hyperpigmentation.

  • History of exposure and location of rash is crucial to assess.

Discoid Eczema / Nummular Eczema

  • Round or oval patches of inflamed skin, very itchy, mostly affects arms and legs.

  • Can last for months to years if untreated and often starts as small spots that grow rapidly.

Pompholyx

  • A form of hand/foot eczema characterized by blisters.

  • Common in young adults, can be triggered by contact allergens, stress, and certain medications.