Why do the corners of my mouth split?

A couple of years ago I had a problem with my mouth – both the corners started splitting, causing very painful open sores. I still get these every now and again, and wanted to let people know what the cause is for me in the hope it might help others.

I was going to add a photo showing Angular Cheilitis, but I think this might put people off visiting my blog!

Searching for a solution

At first, I thought they were cold sores, and used the relevant treatment from the chemist. I usually use Zovirax for cold sores, but this just wasn’t working.

I try to be health conscious and thought it might be some sort of vitamin deficiency. I thought it unlikely, as I already take a number of supplements, but decided to do some research into this problem with my trusty friend Mr Google.

The medical term for this sort of problem is Angular Cheilitis, and it’s cause seems a bit of a mystery. Is it a cold sore? Is it an iron / vitamin B / vitamin C deficiency? Is it an infection?

I tried boosting my intake of these vitamins and iron, but nothing seemed to work.

In fact, the sores seemed to be getting worse, and I found myself constantly applying vaseline or lip balm to sooth the sores. I even wondered if this was causing the sores to get worse.

The surprise discovery

After a couple of months, I was driven mad with this, and even considered taking a day off work to visit my doctor. (I was working on a contract, so wouldn’t have been paid for a trip to the doctor!)

By chance, I happened to be talking to a colleague about this and he said he had exactly the same problem in the past. He went through the same process of trying different treatments, until he discovered the cause:


Yes, that’s right. It was the toothpaste he was using at the time that caused his problem. I thought back to when this problem started, and we had changed our brand of toothpaste just a week or so before it developed.

I immediately changed back to my old toothpaste, and to my amazement, the sores went away within a week.

I had nearly forgotten about this, but in the last few days I have been getting a tingle in the corners of my mouth – a sign that they might be splitting soon. And guess what? We recently changed brand of toothpaste again!

I would like to do more research into the ingredients that cause this, so will be keeping a list of toothpastes that cause it. So far, I have two –

Aquafresh – one of their stripy varieties. I try to avoid all stripy ones these days.

Pronamel – Gentle Whitening variety. I have used some other Pronamel toothpastes without any problem.

Having lived with these sores for nearly two months in the past, and knowing the embarrassment it causes, I hope that this might help someone out there.

Here’s a disclaimer in case one of these toothpaste companies tries to sue me – This post in no way attempts to prove that there is a link between toothpaste, in particular the brands mentioned, and Angular Cheilitis. Everything written here is my own opinion and is based on my own experience.

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