Be aware that lisinopril or other ACE inhibitors may cause burning mouth syndrome

Burning mouth syndrome is an uncomfortable burning sensation in the mouth and/or tongue without any oral mucosal lesions, sores or other physical abnormalities. It can manifest as pain, altered sensation and taste, and irritation of the oral mucosa. 

Burning mouth syndrome usually occurs bilaterally, but can be confined to one side of the mouth. It predominantly affects middle- to older-aged women and can result in a reduced quality of life. Several drug classes have been linked to the development of burning mouth syndrome; antihypertensives are the most common, with those affecting the renin–angiotensin system being the best documented in the literature.

A recent care report highlights the importance of recognizing the possibility of this syndrome being caused by angiotensin-converting enzyme (ACE) inhibitors, specifically lisinopril. A 70-year-old woman with a history of hypertension, depression, type 2 diabetes and osteoporosis presented to a primary care clinic with complaints of dryness and a burning sensation in her mouth. Symptoms had been ongoing for more than five years, with some recent progression. Her symptoms led to decreased appetite, frustration and a reduced quality of life.

Local and systemic causes of burning mouth syndrome range from allergens, toxins and physical irritation, to Sjögren's syndrome, vitamin deficiencies and neuropathies. These potential causes were ruled out and a thorough laboratory work-up showed no abnormalities. Drug-induced causes were then considered. She was counselled to stop taking escitalopram (for depression), but her symptoms remained. The burning pain was suspected to likely be neuropathic in nature, so gabapentin and pilocarpine were started, with minimal improvement and more adverse events. 

At her next visit to her primary care clinic, she was switched from lisinopril to another antihypertensive agent. Two weeks after this medication change, the patient reported substantial improvement in her symptoms.

In patients presenting with burning mouth syndrome with no readily identifiable causes,  check to see whether the patient is taking an ACE inhibitor and try switching the patient to a different antihypertensive. It is important for healthcare providers to recognize this uncommon adverse event of ACE inhibitors, as it may be overlooked and lead to unnecessary investigations and prescribing cascades. 

Reference

1. Sridhar N, Tosur Z. Lisinopril-induced burning mouth syndrome. Ann Intern Med Clin Cases 2023;2:e221103. (accessed May 9, 2023).