Lecture 4 Eczema Flashcards
T cell responsible for acute stage of eczema
Th2
T cel responsible for chronic sage of eczema
Th1
Clinical features of Atopic eczema
• Itchy skin condition in the last 12 months
Plus 3 of the following: • Onset before age 2 • History of flexural involvement • History of generally dry skin • History of other atopic disease • History in 1st degree relative if under 4 yrs
Pathogenesis of Eczema
– Key role for Filaggrin gene
– Atopic family history
- Epidermal barrier dysfunction
- Environmental factors
- Immune system dysregulation
Pathology of eczema
- Spongiosis (intercellular oedema) within the epidermis.
- Acanthosis (thickening of the epidermis).
- Inflammation - Superficial perivascular lymphohistiocytic infiltrate
Histological features of acute dermatitis
Oedema in epidermis
superficial perivascular infiltrate with lymphocytes, histiocytes and occasional neutrophils and eosinophils.
Histological features of chronic dermatitis
- Chronic spongiotic dermatitis- degree of spongiosis is often mild and difficult to appreciate
- Significant acanthosis which may show a psoriasiform pattern with hyperkeratosis, hypergranulosis and miminal parakeratosis.
- Fibrosis of the papillary dermis may be present.
Clinical features of Atopic dermatitis/eczema
• Itch • Distribution – Flexures, Neck, Eyelids, Face, Hands and feet – Tends to spare nappy area • Acute changes – Pruritus, Erythema, Scale, Papules, Vesicles – Exudate, crusting, excoriation • Chronic changes – Lichenification, Plaques, Fissuring
External types eczema
• Contact dermatitis – Irritant – Allergic • Lichen simplex • Photoallergic or photoaggravated eczema
Internal types of eczema
– Atopic – Discoid – Venous – Seborrhoeic dermatitis – Pompholyx – Juvenile plantar dermatitis • Asteatotic
What type of sensitivity is allergic contact dermatitis
Type 4 Hypersensitivity
Delayed can take 48-72 hours
What are the causes of irritant contact dermatitis
- Friction- micro-trauma, cumulative
- Environmental factors
– Overexposure to water
– Chemicals such as acids, alkalis, detergents and solvents
What occupations increased for risk of developing irritant contact dermatitis
Hairdressers
NHS staff
Cleaners
Describe the process of patch testing
- Applied Monday (3 days)
- Remove Wednesday
- Re-assess Friday (2 days after removing)
What is Seborrhoeic dermatitis in infants
- Distinctive pattern
- Predilection for scalp, proximal flexures.
- <6months age usually.
- Often clears within weeks of treatment
What is Seborrhoeic Eczema- Adults
- Malassezia yeast increased in the scaly epidermis of dandruff and seborrehoic dermatitis.
- Red, sharply marginated lesions covered with greasy looking scales.
- Distinctive distribution – areas rich in supply of sebaceous glands (scalp, face, upper trunk
How do you treat Seborrhoeic Eczema- Adults
• Treat with topical anti-yeast (ketoconazole).
Describe discoid eczema
- Circular plaques of eczema.
- Cause often unknown.
- May develop at sites of trauma/irritation
Clinical features of Pompholyx/Vesicular Eczema
- Palms and soles.
- Intensely itchy.
- More common under 40 years.
- Sudden onset of crops of vesicles.
- Resolution can include desquamation
Clinical features of Asteatotic eczema
- Very dry skin.
- Cracked scaly appearance.
- Most commonly shins affected.
- Climate – heat
- Excessive washing/soaps
Clinical features of venous Eczema
- Increased venous pressure.
- Oedema.
- Ankle and lower leg involved.
- Resolution of oedema can help – compression stockings.
Topical steroids that can be used to treat eczema
- hydrocortisone (low)
* Betamethasone (potent)
Calcineuron Inhibitors that can be used to treat eczema
– Topical Pimecrolimus and Tacrolimus
Treatment for severe eczema
• Ultraviolet light. • Immunosuppression. – Azathioprine – Ciclosporin – Mycophenolate mofetil – Methotrexate
