Atopic Eczema Flashcards
What is Atopic Eczema? Ex and RF?
- Breakdown of the skin barrier due to an inflammatory and allergic response.
Ex: - 20% of children in UK, onset in 1st year of life
- Unlikely to be in the first 2 months - differentiating it from the infantile seborrhoea dermatitis.
-1/3rd will develop asthma - Resolves in 50% by 12 yrs and 75% by 16 yrs
RF: - FH of atopic disorders e.g. eczema, asthma, allergic rhinitis (hay fever)
Clinical presentation of Atopic Eczema? Ddx?
1) Itchiness (pruritus) is the main symptom and results in scratching and exacerbation of rash (itching always present)
2) Affected areas become erythematous and crusted
3) Atopic skin - dry, prolonged scratching and rubbing - leads to lichenification (thickened, leathery patches of skin)
4) Distribution - infants (> 2 months) - mainly face and trunk, older children - flexor and friction surfaces.
Ddx: Infantile seborrhoea dermatitis (most common in first 2 months of life)
Causes of exacerbation of eczema?
1) Easily infected by bacterial infection (Staph/Strep)
2) Viral infection (Herpes simplex can spread rapidly on atopic skin)
3) Ingestion of allergen - e.g. egg
4) Contact with an irritant/allergen
5) Environment - heat or humidity
6) Psychological stress
Treatment of Atopic Eczema?
- Avoid irritants - soap, avoid nylon and wool (cotton clothing only)
- Nails should be cut short to reduce skin damage from scratching
- Dietary elimination of allergic foods
- Psychosocial support for severe eczema
Medication:
- Complete emollient therapy (E45 cream) - artificial restoration of the defective skin barrier.
Topical steroids:
- Mild - topical hydrocortisone (twice a day)
- Severe - Clobetasol butyrate (keep to minimum, only in acute exacerbations, systemic S/E and thinning of skin with overuse)
Immunomodulators:
- In children over 2 years old (topical tacrolimus)
Occlusive bandages:
- Helpful over limbs when scratching or lichenification, contains zinc and worn overnight for 2-3 days till improvement.
Antibiotics:
- Abx with hydrocortisone applied topically, systemic antibiotics for more widespread for severe infection.
Antihistamines:
- Help to raise itching threshold so that scratching is reduced, non-sedative 2nd gen AH - Fexofenadine.
What is Stephens- Johnson syndrome? Ex and Ax?
- Immune-complex-mediated hypersensitivity disorder.
- Varies from mild skin and mucous membrane lesions to a severe, some times fatal systemic illness - toxic epidermal necrolysis (TEN).
Ex: F>M, vague URT symptoms occur 2-3 weeks after starting a drug and then 2 days later a rash that affects <10% of body develops.
Ax: Drugs:
1) Allopurinol
2) Carbamazepine
3) NSAIDs
4) Penicillins
Clinical presentation of Stephens-Johnson syndrome? Dx?
1) Painful erythematous macules evolving into target lesions.
2) Severe mucous ulceration in >2 surfaces: eyes (conjunctivitis, corneal ulceration, uveitis) oral cavity, urethra
3) Toxic epidermal necrolysis (TEN) - flu-like symptoms may preceded skin involvement which affects >30% of body surface.
- Widespread painful dusky erythema.
Dx - CLINICAL
Treatment of Stephens-Johnson syndrome?
1) Supportive + Manage in ICU
2) IV immunoglobulins
3) AVOID sytematic/topical corticosteroids - increase infection risk
Acute Urticaria brief:
- Resolves within 6 weeks
- Allergy such as food or drug reactions (penicillins, thiazide, captopril) or infection are common triggers
Chronic Urticaria?
- Persistant for > 6 weeks
- NON-ALLERGIC
- Local increase in permeability of capillaries and venules
Clinical presentation of Urticaria?
- Itchy erythematous wheels that move around and appear rapidly after drug exposure.
- Can be accompanied by tongue swelling of the soft tissues of the eyelids, lips and tongue - ANGIOEDEMA
Treatment of Urticaria?
1) 2nd generation antihistamine - Fexofenadine
2) Consider IV corticosteroids - IV Hydrocortisone or adrenaline e.g. IM Adrenaline if there is anaphylaxis
Allergic Rhinitis & Conjunctivitis (hay-fever) brief?
Inflammatory disorder whereby nose and eyes become sensitised to allergens - can be atopic (IgE antibodies to inhalant allergens) or non-atopic. Can be seasonal (grass, weed, tree pollens) or perennial (perennial allergens include house-dust mite and pets).
Ex: Up to 20% of children and severely disrupts their lives.
RF: Eczema, asthma, sinusitis
Clinical presentation of hay-fever?
1) Coryza/ rhinorrhoea, conjuctivitis
2) Though-variant rhinitis - cough due to post-nasal drip, chronically blocked nose causing sleep disturbance and impaired daytime behaviour and concentration
Treatment of hay-fever?
1) Antihistamines - Fexofenodine
2) Inhaled corticosteroid - Beclometasone
3) LRA - Montelukast
4) Eye drops - Cromoglycate
Nasal decongestants
What is anaphylaxis?
An acute, severe, life-threatening allergic reaction in pre-sensitised individuals, leading to a systemic response caused by the release of immune and inflammatory mediators by basophils and mast cells.
