Dual symptomatic and exudative nasal responses are not characteristics of perennial allergic rhinitis

Acute and late phase (dual) symptomatic responses after allergen challenge commonly occur in allergic asthma. The aim of the present study was to expl ore the occurrence of allergen challenge-induced biphasic responses in pati ents with chronic perennial allergic rhinitis living in an area with high h ouse dust mite (HDM) exposure. Fifteen patients with perennial rhinitis and evident allergy to HDM participated. Nasal challenges with HDM and sham we re performed on separate days in a crossover design. Nasal symptoms, forced expiratory volume in 1 s (FEV1) and orally exhaled nitric oxide were recor ded every hour for up to 8 h after each challenge. alpha (2)- Macroglobulin and eosinophil cationic protein (ECP) were analysed in hourly nasal lavage s, and nasal histamine provocations were carried out after 8 h. HDM, but nu t sham, caused an immediate increase in nasal symptoms which gradually abat ed over the 8-h period. No reoccurrence of nasal late phase symptoms was se en. HDM, but not sham, induced an early increase in alpha (2)-macroglobulin and ECP levels; both indices remained elevated fur up to 3 h after challen ge. HDM challenge evoked hyper-responsiveness to histamine expressed as inc reased nasal symptoms (p < 0.05; HDM vs sham). No differences in exhaled ni tric oxide or FEV1 were demonstrated at any one time point between the HDM- and sham-challenged days. It is concluded that nasal symptomatic and exuda tive late phase responses may not be a general Feature, even in subjects wi th perennial rhinitis challenged with high, symptom-provoking, doses of HDM allergen.