Biotin is a component of the B-complex vitamins that has been widely used in over-thecounter supplements. The effects of biotin on thyroid function tests (TFTs) have been recently reported by multiple authors. We report here a case of a patient who presented with TFTs consistent with hyperthyroidism and a positive radioactive iodine uptake (RAIU) scan while taking biotin supplements. The TFTs normalized almost a month later and continued to be normal even after resumption of biotin supplements. Interpreting TFTs while patients are taking biotin could pose a diagnostic challenge, so we suggest more frequent monitoring for those patients before starting them on long-term anti-thyroid medications.

Strongyloidiasis is one of the neglected helminths infection that is often underdiagnosed and undertreated. Due to its variable presentation, its diagnosis is often a challenge. We report a case of an immigrant patient with asthma who later developed eosinophilia. After 3 years of unexplained eosinophilia, he developed B symptoms and had frequent asthma exacerbations. He was later diagnosed with strongyloidiasis and treated with ivermectin. His B symptoms resolved, and his asthma exacerbations decreased significantly. Due to the frequent use of corticosteroids in asthma exacerbations, this case illustrates the importance of Strongyloides screening in asthmatics from high-risk regions. It also displays the importance of further investigating patients with asthma who develop eosinophilia and have frequent exacerbations while on optimal asthma treatment. Having a high index of suspicion is essential when making this diagnosis, as clinical presentation is often variable and does not follow a standard time course.