Skinned knee has turned to blister

my husband skinned his knee quite badly about 3 weeks ago.  We used betadine and kept it clean. The scab had come off and it just looked like his knee was bruised it was kind of a purplish color. He scratched his knee yesterday just like an itch and now there is a large blister that has appeared suddenly where the the original skinned knee was.  Any ideas?  Please?  what should i be doing?

[jagesh50]

Possibly a sensitization to iodine.Change the antiseptic lotion.Nothing else of concern.

[Bhupinder Kaur, MD]

Hello,
This blister appears to be a friction blister which is formed as a result of grazing the knee. Wash the areas several times with fresh water. Do not use any cosmetic products at the sites. You can apply some calamine lotion at the rash as it will help in soothing the skin.Also ask him to wear cotton clothes and do not burst the blister..Application of mild corticosteroid cream and oral antiinflammatories like ibuprofen/acetaminophen are also helpful.If the symptoms are severe then it will be best to consult a dermatologist
I hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.