Blister forming over previous wound scar

[Shells_Shel]

At the end of June I had an accident with my bicycle and fell which resulted in my knee becoming scraped up, bruised and sore.  I was able to move it full range of motion and cleaned out the abrasions myself so I did not consult a doctor.  About 10 days ago, I noticed soreness on my knee and upon examination there is a blister that has directly formed over the scar from the abrasion.  It fills with clear slightly tinged fluid, and then if bumped it gets a hole in it and drains.  Sometimes it drains spontaneously without being touched.  It has stayed continous for the past 10 days.  I have had some sharp pains on and off that feels like it is coming from deep within the knee.  What could be causing this?  It does not appear to look outwardly infected.  

[Drpedsben]

And yea one thing I forgotten to mention. There is sharp pain like the ones one would experience with any other blisters anywhere.

Thanks for your advice in advance guys!

[Drpedsben]

Hey guys,

About a month back I sustained 2, as far as I know, superficial wounds at my patellar area (actually towards the right of my patella). So the 2 wounds had already healed by itself leaving 2 very obvious scab-like scars at the site of the wounds.

So I did deadlifts just last Friday and realized after I headed home that a small blister had actually grown underneath the wound (the one directly beside the patella). Not sure if this was due to the deadlifts. I admit that I was hitting 160kg with proper form. So any suggestions what the blister could entail? I read the post above and found much similarities to mine.

Main questions are: Should I be worried? What should I do?

[Arti Sharma, M.D.]

Hi there!
It is possible that there is a swelling of the bursa at the front of the knee resulting in acute prepatellar bursitis. A direct blow to the knee can lead to this condition. There is rupture of blood vessels which bleed into the bursa leading to swelling and triggering an inflammation reaction in the walls of the bursa. The swelling may reduce but tenderness persists due to the thickening of the walls. Any surface injury can trigger acute bursitis. Bacteria enter the fluid within the prepatellar bursa causing infection. There is a focus of infection under the knee joint. You should visit an orthopaedician as soon as possible otherwise the infection can spread further. Seek medical help. Do keep us posted on how you are doing.
Take care and regards!

[chelio]

I have what seems like the identical condition shells has, only on my elbow. A bike accident scrape that healed completely and the scab had fallen off. Then a week later a blister formed that breaks, stings, and then reforms over the pink scar tissue. It stings the way any broken blister stings, not like a elbow injury. I've had this now for a week. I cover it with bandage and antibiotic ointment at night for comfort. But I just stays there.

[Kennalee]

I am having exactly what she is having. It is on the skin and has in 2 days refilled and I have had to remove the fluid due to it being very uncomfortable. Yesterday the fluid was clear. Today the fluid was pink. Should I see my dr and get antibiotics or just continue to remove the fluid when it is on top of my scar. The only friction on my knee is my pant and they are strait legged pants, no tightness or friction. Once I drain it it hurts a little but no deep pain. The scrape took 3 weeks to heal as it was a deep abrasion.  I was so happy it was gone until yesterday when I noticed the 1st blister. Then today when it was clearly filled again.

[j_scala88]

Anyone have a follow-up? This exact same thing is happening to me on a wound on my knee, it was initially infected and then treated with antibiotics, then it healed and scarred over. I've been applying aquaphor regularly to reduce the appearance of the scar and after skating yesterday (a knee pad) I've noticed that a blister has formed over the scar.