Infectious blisters on pointer finger of a child.

My friends daughter is 5 yo and lives in Northern Thailand with her parents, my friends.
About a week ago she got a little blister on her right pointer finger and this has now developed into blisters now covering the whole finger and starting to go onto the palm.
The Thai doctors don’t know what is happening, despite undertaking all sorts of tests.  
She is having surgery tonight to remove some of the worst of the blackened and dead skin on her finger tip underside.
It is obviously a pretty painful and traumatic time and I'd like to help with some proper advice on possibilities.
They have sent a photo of the hand.  The blisters are white with clear fluid and are red-rimmed.  The whole finger underside is involved.  She is otherwise well.
What could this condition possibly be?

[Alan Rockoff, MD]

This looks like primary herpes simplex.  She might have gotten it from touching the mouth of someone with a cold sore.  I recommend culturing for herpes and starting treatment with an antiviral medication like acyclovir.  I assume that bacterial cultures have already been performed and child started on oral antibacterial antibiotics.  If it is herpes, it should heal without incident, though it may recur in mild form from time to time.

Best.

Dr. Rockoff