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BACKGROUND: Besides allergens, pollen release bioactive, low molecular weight compounds that modulate and stimulate allergic reactions. Clinical relevance of these substances hasn't been investigated to date. OBJECTIVE: To elucidate the effect of a non-allergenic, low molecular weight factors from aqueous birch pollen extracts (Bet-APE

Exposure to welding fumes is a recognized respiratory hazard. Occupational asthma but not occupational rhinitis has been documented in workers exposed to steel welding fumes. We report a 26-year-old male with work-related rhinitis symptoms as well as lower airways symptoms suggestive of occupational asthma and metal fume fever associated with exposure to steel welding fumes. The diagnosis of occupational rhinitis was confirmed by specific inhalation challenge.

Clin. Otolaryngol. 2010, 35, 462–467 Objectives: To assess the correlation between acoustic rhinometry and visual analogue scale endpoints in the context of nasal challenge with occupational agents. Design: Prospective controlled study. Setting: University teaching hospital. Participants: Sixty-seven subjects with a history of work-related rhinitis and asthma symptoms. Main outcomes measures: Subjects underwent nasal challenge with control and specific agent on consecutive days. Nasal congestive response to challenge was monitored by acoustic rhinometry and visual analogue scale. Results: Results showed no correlation between visual analogue scale and acoustic rhinometry measurements at baseline on the control (r = −0.13, P = 0.3) and active (r = 0.14, P = 0.2) challenge days. No correlation was found between acoustic rhinometry and visual analogue scale when analysing all measurements obtained at all times after challenge with the control and active agent (control: r = 0.09, P = 0.04; active: r = 0.001, P = 0.9). The correlation between acoustic rhinometry and visual analogue scale was good and significant (r = −0.62, P = 40% from baseline values. Conclusions: We showed that the correlation between acoustic rhinometry and subjective nasal patency was poor on steady conditions. However, a significant correlation was observed in those cases showing a greater nasal congestive response after challenge measured by acoustic rhinometry.

Nasal challenge with allergen or mediators is a useful model to understand the pathophysiology of allergic rhinitis. Some mechanisms have thereby been clearly clarified. Different methods have been proposed to mimic the natural allergen exposure and to measure the clinical and biological responses. Nasal challenges can also be used in clinical practice, mainly when there is a discrepancy between results of skin tests and in vitro or when occupational allergens are involved. Nasal challenges are also valuable to assess the efficacy of specific immunotherapy or some drugs.

Background: A link ("naso-bronchial reflex") between nasal and bronchial reactivity seems to exist. The effect of nonspecific nasal challenge (standing for the exposure to irritative stimuli at the workplace) on lung function indices and nonspecific bronchial reactivity is not known. Methods: In 80 healthy workers (age: 36.0 +/- 8.6 years) continuously exposed to acceptable levels of different respiratory irritants (for more than 2 years) nasal challenge was performed by spraying doubling concentrations of histamine (0.0625-16.0 mg/mL, doses of histamine: 7.8 mu g-2.08 mg) into each nostril. Before and immediately after nasal challenge spirometry and the bronchoprovocation test with histamine (0.5-128 mg/mL) was performed Results: Although nasal challenge with histamine had not reduced airway caliber (before nasal challenge vs, following nasal challenge: FEV1 3.8 +/- 0.8 vs. 3.7 +/- 0.8 L, and MEF50 4.3 +/- 1.4 vs. 4.3 +/- 1.4 L/s, mean +/- SD, respectively), it had significantly reduced nonspecific bronchial reactivity in 30.2% of the irritant-exposed subjects. Conclusions: Nasal challenge with histamine decreases nonspecific bronchial reactivity in workers occupationally exposed to respiratory irritants. Thus, a methodological implication would be that these two tests should not be performed consecutively in less than 2 hr in the same subjects.

Summary We evaluated the effect of pre-treatment with 1 and 2 mg b.i.d. of ketotifen on the early response to nasal challenge in a double-blind cross-over trial. Weekly nasal challenges were performed in 10 allergic subjects after 1 hr and 1, 2, 3 and 4 weeks of ketotifen administration. The response to nasal challenge was monitored by counting the number of sneezes, the assessment of subjective symptoms, and by measuring the levels of histamine and TAME-esterase activity in recovered nasal lavages. The number of sneezes diminished significantly after a single dose of drug with both the 1 and 2 mg doses. Prolonged pre-treatment did not improve the results. The levels of histamine and TAME-esterase activity in recovered nasal lavages were not changed significantly by either pre-treatment at either dose. Although the number of subjects was small, our data suggest that ketotifen diminishes allergic symptomatology by its antihistaminic properties rather than by inhibiting histamine release from mast cells. As we did not look into the effects of ketotifen on other products generated by mast cells (prostanoids, leukotrienes and tryptase), we cannot fully rule out an effect on mast cells.

Most extracts used in hyposensitization are complex and ill-defined mixtures of a large number of antigenic components. A highly refined (purified) and well-characterized allergen preparation from Timothy pollen (Phleum pratense) is now available. This paper describes the results of hyposensitization for 3 years comparing the purified preparation Timothy N, the crude extract Timothy O and a four-grass mix in sixty patients with allergic rhinitis due to grass pollen. The sixty patients were randomized into three groups and compared with a control group not hyposensitized. All three groups showed a significant decrease in clinical symptoms compared with the control group. The Timothy N group had a significantly higher nasal tolerance shown by nasal challenge test after 3 years' treatment than the group treated with the crude extract (P = 0.05). In addition, the Timothy-N-treated patients needed significantly less antihistaminic medication than the patients having received the crude extract or the four-grass mix (P = 0.02 and P = 0.01, respectively).