What the hell is this?

[DaRuckus337]

Looks like a hypersensitivity (some type of allergic response), but it's obviously impossible to tell from a small photo. Is it hard? Painful to the touch? Itchy? Does it have texture or is it smooth? Certainly, you should find a doctor (dermatologist would be best for starters), but judging by the appearance of it and the rapid change in morphology, it looks like some classic contact dermatitis to me. It certainly doesn't look like ringworm or any contagious skin infection. Make sure to think back to what substances might have been on your clothes/skin for the 48 hours prior to the reaction (many types of dermatitis take ~48 hours to develop a rash, so it did not have to be a substance you touched just before getting the rash), so you can help your doctor out with finding the cause.

 

[Matt Majorz]

Mat Crabs...nah j/k...Looks like an allergy type of thing. Possibly eczema(sp)?

 

[fedorheartsyou]

Went to the docs and it was just an allergic reaction to something.

 

[ahcshon]

man just looking at those pics is making me itchy.

 

[SMillard]

WTF ... must be some sort of allergic reaction, go see the doc. I don't think anything like ringworm or staph can blow up that fast.

yes they can, unfortunately. He said it was on his leg than went away and is now on his side, that does not sound like staph or ringworm.

 

[jdm_boy]

sorry to say this, but looks like you have the case of "Knee Herpes"