Taste and Smell Disorders in Children and Young Adults With Cystic Fibrosis and Primary Ciliary Dyskinesia-A...

In cystic fibrosis (CF), the defect of the CF transmembrane conductance regulator (CFTR) can also affect sensory nerve cell function, as recently demonstrated in animal models. The aim of this prospective cohort study was to investigate whether taste and smell disorders in CF correlate with persistent CFTR dysfunction detectable by iontophoresis or rather with inflammation or lung function. Participants with primary ciliary dyskinesia (PCD) and controls without pulmonary disease served as comparators.

In 65 participants (age median 19 years IQR [12-26]; CF n = 23, PCD n = 22, controls n = 20) at the University Children´s Hospital Bochum, we measured taste (salty, sweet, sour, bitter) at four concentrations ("Taste-Strips," score 0-16, hypogeusia age-adjusted < 8/< 9/< 9.9/< 10 points) and smell ("U-Sniff"-test, score 0-12, reduced odor identification performance < 8 points), pilocarpine iontophoresis, spirometry, inflammatory markers (e.g., CRP) and subjective chemosensory impairment.

Chi²/Fisher's-exact, Mann-Whitney-U, Kruskal-Wallis, linear regression; p < 0.05.

Hypogeusia occurred only in CF (17.4%). Particularly misidentification of the taste "salty" occurred significantly more frequently in CF (34.8% vs. PCD 19.3% and controls 17.5%), especially in the CF subgroup with elevated sweat chloride ≥ 60 mmol/l. Reduced odor identification performance was significantly more common in PCD (30% vs. CF 4%). Chemosensory disorders were not related to current lung function or inflammation.

Taste disorders in CF are mostly attributed to difficulties tasting salty and are associated with elevated sweat chloride, probably caused by increased salivary salt following CFTR dysfunction in salivary glands rather than in the nerve cells. Smell disorders, however, remain a significant issue, particularly in PCD.