Topical lidocaine was not shown to improve oral intake but did relieve pain in children with oral ulcers.
Why does this matter?
We often prescribe topical viscous lidocaine for children with gingivostomatitis or hand, foot, and mouth. The thought is it will relieve pain and allow them to orally hydrate. But does it actually help?
Mouth sores are a pain…
This was a brief systematic review of two RCTs on topical lidocaine for oral ulcers. One found no difference in short term oral fluid intake but did not measure pain scores. The other did not measure oral fluid intake but found improved pain scores with lidocaine. Both included children from 6 months to 8 years. I have a few thoughts. First, I think pain relief alone is a good enough indication to use this. I am surprised oral intake wasn’t better. It may have been that the short-term target goals were too ambitious in the included study. Remember, lidocaine may be toxic, with risks of seizure and even cardiac arrest reported. I usually ask parents if the child is able to brush teeth and spit the toothpaste out reliably. If so, I will use swish and spit. If not, I won’t. In very young children, lidocaine can be applied with a cotton swab. Bear in mind, repeated high dose mucosal exposure may still result in systemic absorption and toxicity, even if not swallowed. Make sure parents understand that it must be used under supervision, every 3-4 hours or so. The maximum dose should not exceed 4.5mg/kg/dose. That might sound like a lot, but a 4% topical concentration of lidocaine means 4000mg/100mL; 40mg per 1mL; 200mg/5mL. That is means in a 20kg child, the max dose of 4% is just 2.25mL. Be careful. I am on board with using this treatment. Sometimes it works like magic.
BET 2: Does topical lidocaine improve oral intake in children with painful mouth ulcers? Emerg Med J. 2020 Feb;37(2):113-114. doi: 10.1136/emermed-2019-209390.3.
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