Introduction:
Nasal allergen challenge (NAC) allows the differentiation between silent sensitization and clinically relevant allergy. It is essential to record the clinical symptoms for the evaluation of positive and negative NACs. This study evaluates the use of the visual analogue scale (VAS) to detect these symptoms.
Methods:
73 NACs were performed. The following data was collected at baseline and after diluent and allergen challenge: (I) nasal flow (anterior rhinomanometry), (II) symptom score according to the DGAKI NPT guideline, (III) severity of the symptoms obstruction, secretion and itching via single VAS (100 mm, "min" to "max"). A VAS total score was calculated as the sum of the three VAS scores.
Results:
In 13 cases, the NAC was discontinued due to a nonspecific reaction (> 20% flow decrease after diluent application). According to the DGAKI NPT guideline, 36 NACs were rated as positive and 25 NACs as negative. In the group of 36 positive NACs, there was a significant median increase in VAS in the symptoms of obstruction (30 mm), secretion (28 mm) and itching (20 mm), and total VAS score (80 mm) after allergen challenge. In the group of 24 negative NACs, there was a median increase in the total VAS score of 3 mm. In four NACs in this group, however, there was a marked increase in the overall VAS score (77 mm, 77 mm, 148 mm, 181 mm).
Conclusion:
The VAS score can be used to assess clinical symptoms and to evaluate a positive response to the NAC. The marked increase in the VAS score in four NAC in the group of "negative" challenges highlights the need for a differentiated assessment of subjective symptoms.
