Hypogeusia

Causes

Covid-19

COVID-19 causes symptoms that affect the central nervous system (CNS), peripheral nervous system (PNS), and skeletal muscle. Hypogeusia falls under a neurological disease and a PNS symptom, while also being the highest occurring PNS symptom, closely followed by anosmia. Due to hypogeusia being a significant symptom of COVID-19, it is often accompanied by hyposmia, even when many other COVID-19 symptoms are absent. Both can be considered early indications of a COVID-19 infection. Further, hypogeusia is often developed following early symptoms of hyposmia, usually developed from olfactory epithelium damage from upper respiratory infections.

Oral cancer

Hypogeusia tied to oral cancer and tumors can affect sweet, sour, salty, and bitter tastes, but bitter taste hypogeusia occurs significantly more often compared to the rest of the tastes. Inhibition of gustatory papillae found in the base, often due to oropharyngeal tumors, is thought of to be the cause of this. Oral cancer treatments, such as chemotherapy, radiation therapy, and surgical treatments, are further causes of taste and smell loss with up to 70% of oral cancer patients noting dysgeusia. Specifically, chemotherapies and radiation treatments may impair or damage various taste related cells, and certain surgeries may even remove minor to major parts of the tongue depending on the severity of the tumor.

Other

Nutritional zinc deficiency may cause various problems, hypogeusia being one of them. Chronic Rhinosinusitis (CRS) may cause olfactory dysfunction as well as gustatory problems, with either or both leading to the noticeable presence of hypogeusia in CRS patients. The connection between hypogeusia and Parkinson's Disease is less well described. PD patients have an increased dysregulation in their taste receptors, as well as their olfactory receptors. The receptors affected in PD patients were those associated with the perception of bitterness in most cases.

It was determined in 1981 (by researchers of the University of Heidelberg) that pineapple juice can cause acute loss of taste lasting up to 72 hours in individuals with genetic variant CCR5-Δ32.