What causes angular cheilitis and how can itbe treated?

Yeast: This problem is also called perleche and is caused by moisture trapping in the corners of the mouth. First, try applying some otc ketoconazole 1% cream once daily at bedtime. This should clear quickly (3-5 days). This is usually a chronic condition so the using the cream on a regular basis may be needed. If this doesn't fix the problem, see you doctor for help.