Of bugs and drugs. A guide through the labyrinth of antimicrobial therapy for respiratory tract infections

Non-allergic rhinitis: diagnosis and management

Patients in the rhinitis clinic with negative skin prick tests present a challenge. Non-allergic rhinitis consists of a variety of conditions including infection, hormonal changes, drugs and autonomic dysfunction. There is also a range of systemic disorders to be considered. The pathogeneses of many of these are less well understood than that of allergic rhinitis, diagnosis and treatment pathways are also more complex. A detailed accurate history needs to be taken followed by relevant investigations which may include allergen challenge, because skin prick and RAST-negative allergic rhinitis is now recognised. Nitric oxide levels may prove helpful: elevated levels suggest inflammation, very low levels indicate the possibility of primary ciliary dyskinesia or cystic fibrosis. Treatment is of the underlying cause when found: for those without obvious pathology a trial of combined therapy with topical corticosteroids plus antihistamine or plus anti-cholinergic may be worth while. A complex inter-relationship between allergic and infectious rhinitis is becoming apparent.