Derm - Urticaria Flashcards
Defintion
Also known as hives - small itchy lumps that appear on the skin
- associated with patchy erythematous rash
- can be localised to a specific area or widespread
They may be assosciated with angioedema and flushing of the skin.
Classification
Acute urticaria
Chronic urticaria ( > 6 weeks) - autoimmune condition, where autoimmune target mast cells and trigger them to release histamines and other chemicals. It can be sub-classified depending on the cause:
= Chronic idiopathic urticaria
= Chronic inducible urticaria
= Autoimmune urticaria
Aetiology of acute urticaria
Acute urticaria is typically triggered by something that stimulates the mast cells to release histamine. This may be:
Allergies to food, medications or animals
Contact with chemicals, latex or stinging nettles
Medications
Viral infections
Insect bites
Dermatographism (rubbing of the skin)
Chronic idiopathic urticaria
Recurrent episodes of chronic urticaria without a clear underlying cause or trigger
Chronic inducible urticaria
Describe episodes of chronic urticaria that can be indicted by certain triggers such as:
- Sunlight
- Temperature change
- Exercise
- Strong emotions
- Hot or cold weather
- Pressure (dermatographism)
Autoimmune urticaria
Describes chronic urticaria associated with with an underlying autoimmune condition such as SLE
Treatment
FIRST LINE = Antihistamines = fexofenadine of choice for chronic urticaria
Oral steroids may be considered as short course of severe flares
In very problematic cases referral to a specialist may be required to consider treatment with:
- Anti-leukotrines such as montelukast
- Omalizumab which targets IgE
- Cyclosporin
Angiodema
Genera localised swelling which happens on an area most commonly the face.
Can also occur on:
- Genitalia
- Extremities
- Bowel wall
Treatment same as urticaria
Angioedema cause
Allergic reaction
Some specific meds:
- ACE-I!!!
- NSAIDS
- CCB
