Faa use of sedating antihistamines
Antihistamines have no role in the acute management of anaphylaxis.
Antihistamines are used in the management of allergic conditions.
This is less of a problem with newer ‘second generation’ antihistamines, such as loratadine, and ‘third generation’ antihistamines such as desloratadine.
Dose reduction should be considered in patients with severe liver or kidney dysfunction.
Adjunctive treatments such as intranasal ipratropium bromide may be useful in reducing rhinorrhoea in those with perennial allergic rhinitis Seasonal allergic conjunctivitis is typically associated with some degree of allergic rhinitis so allergen avoidance is the first step in management.
Oral antihistamines can be used for allergic conjunctivitis or, if the symptoms are only related to the eye, topical antihistamines with or without mast cell stabilisers are recommended.
Allergic rhinitis refers to nasal inflammation due to the release of histamine and other mediators from Ig E-mediated mast cell degranulation in the nose.
Other conditions may cause similar symptoms, but they can be distinguished from allergic rhinitis by allergy testing to confirm positive allergen-specific Ig E to specific triggers.
Avoiding trigger factors is the first step in the management of allergic rhinitis but some triggers can be difficult to avoid.