How does an allergen cause a release of mediators of inflammation?
Allergen causes IgE synthesis
IgE attached to mast cell surface
Cross linking of IgE by allergen allowing calcium ions entry
Mast cell degranulation and release of mediators
What are the clinical features of allergic rhinitis?
Nasal itching
Rhinorrhoea
Sneezing
Conjunctival symptoms
Do antihistamines penetrate the BBB and have muscarnic side effects?
Yes to both
How do decongestants work?
A- adrenoceptor agonists cause vasoconstriction
Reduce flow mucus
Act locally
What is urticaria caused by?
Release of histamine