Flashcards in Lecture 4 Eczema Deck (24)
T cell responsible for acute stage of eczema
T cel responsible for chronic sage of eczema
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
– 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
• Lichen simplex
• Photoallergic or photoaggravated eczema
Internal types of eczema
– Seborrhoeic dermatitis
– Juvenile plantar dermatitis
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
1. Friction- micro-trauma, cumulative
2. Environmental factors
– Overexposure to water
– Chemicals such as acids, alkalis, detergents and solvents
What occupations increased for risk of developing irritant contact dermatitis
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.
• 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