Psyllium husk (Metamucil®) induced perennial asthma: A case report

Metamucil (R), a soluble fiber supplement for constipation, triggered new onset asthma symptoms in a 44-year-old sensitised nurse after a single inhaled exposure. After the initial event, she had no further exposures. She continued to face challenges with exacerbations, poor asthma control, and chronic cough. Despite 30 years of clinic follow-up, her asthma remained difficult to manage, requiring chronic prednisone. While tapering off corticosteroids, she developed polymyalgia rheumatica. This case underscores that psyllium in Metamucil (R) can cause reactions ranging from mild to severe, even with a single inhaled exposure, emphasising the need for caution in those without a history of asthma.