Oral antihistamines for the symptom of nasal obstruction in persistent allergic rhinitis--a systematic review of randomized controlled trials.
BACKGROUND
Oral antihistamines are recommended by a World Health Organisation working group as a first-line pharmacological treatment in mild persistent allergic rhinitis. There is, however, uncertainty with respect to their effectiveness for a common symptom, that of nasal obstruction.


OBJECTIVE
To test the null hypothesis that oral antihistamines have no effect on the symptom of nasal obstruction in a clinical setting in patients with persistent allergic rhinitis.


METHODS
Protocol based review of double-blind randomized controlled trials of oral antihistamine (i.e. drugs considered to act as a histamine receptor type-1 antagonist) vs. placebo. A search was carried out for published and unpublished trials. Individuals had to be age 12 years or older (with a diagnosis confirmed by skin prick tests, IgE blood tests or nasal allergen challenge), experiencing their normal allergen exposure. A symptom score for nasal obstruction had to be recorded. Predetermined quality criteria were applied. Treating their data as 4-point scores, a meta-analysis was carried out for studies, which provided enough data to be pooled.


RESULTS
Meta-analysis found a weighted mean difference of -0.52 in favour of treatment for patient-assessed symptom scores (95% confidence interval (CI)-0.73,-0.31, P<0.00001), and of -0.33 in favour of treatment for healthcare worker assessed scores (95% CI -0.49, -0.16, P = 0.0001).


CONCLUSIONS
Oral antihistamines cause statistically significant improvement in the symptom of nasal obstruction in patients with persistent allergic rhinitis.
Hore
I
I
The Royal National Throat Nose and Ear Hospital, London, UK. ianhore@yahoo.co.uk
Georgalas
C
C
Scadding
G
G
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D004311:Double-Blind Method; D006634:Histamine H1 Antagonists / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D008875:Middle Aged; D015508:Nasal Obstruction / Q000188:drug therapy* / Q000276:immunology; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic; D012221:Rhinitis, Allergic, Perennial / Q000150:complications / Q000188:drug therapy*; D016896:Treatment Outcome
D006634:Histamine H1 Antagonists