Derm - Urticaria

Question 1

Defintion

Answer 1

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.

Question 2

Classification

Answer 2

Acute urticaria
Chronic urticaria - 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

Question 3

Aetiology of acute urticaria

Answer 3

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)

Question 4

Chronic idiopathic urticaria

Answer 4

Recurrent episodes of chronic urticaria without a clear underlying cause or trigger

Question 5

Chronic inducible urticaria

Answer 5

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)

Question 6

Autoimmune urticaria

Answer 6

Describes chronic urticaria associated with with an underlying autoimmune condition such as SLE

Question 7

Treatment

Answer 7

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