To determine whether a viral upper respiratory tract infection can alter the responsiveness of the nasal mucosa, paired intranasal histamine and cold air challenge sessions were performed before and after (8 to 13 days) experimental rhinovirus infection in 18 nonallergic subjects and 20 subjects with seasonal allergic rhinitis. The nasal response to the challenges was measured as symptom scores for rhinorrhea and congestion, counts for sneezing, weight for expelled secretions, and inspiratory conductance for nasal patency. For both sessions, a greater response was observed in allergic subjects for sneezing, symptoms of rhinorrhea and congestion, secretion weights provoked by histamine challenge, and secretion weights provoked by cold air challenge when compared with the nonallergic subjects. A comparison of the responses to the paired challenge sessions showed greater responses for sneezing, secretion weight and rhinorrhea to histamine and for secretion weight to cold air challenges performed after rhinovirus infection. No differences were observed between allergic and nonallergic subjects with respect to the degree of enhanced responsiveness secondary to viral infection. These results document an increased responsiveness of the nose to these stimuli during the postsymptomatic period of a rhinovirus infection in both allergic and nonallergic subjects.