What are the accurate diagnostic methods for recurrent sebaceous cyst present in the scrotum?

Hi doctor,

I am really sorry for the long explanation, as I will need to give you full details of what has been going on until now. My 22-year-old son has had two incision and drainage (I & D) procedures for an abscess within 2 months. These were due to a boil infection on his scrotum that was not responding to antibiotics. There has been a recurring boil infection, and three courses of Flucloxacillin antibiotics were completed. When they did the first incision and drainage, the infection did not clear up. After five weeks, the wound kept discharging and was not healing properly, so they did a second incision and drainage. So, basically, this happened twice. I am attaching some images. My son had a recurring boil or bump infection, which he noticed suddenly when it was painful, tender, red, and later burst with some pus. Because the antibiotic (Flucloxacillin 500 mg) was not clearing the infection, they did incision and drainage to clear it. I have attached some pictures of the boil with abscess that we took before the first done incision and drainage. Now it is almost six weeks since they did the second incision and drainage, but the wound does not seem to be healing properly. I am attaching images of the latest wound. Nurses are saying that this wound is over granulated. The Urology department requested an MRI to find out if it is a sebaceous cyst inside or a fistula causing this problem. The MRI was done, but the results will come after two to four weeks, so we cannot follow up because the healthcare system is very slow in our country. I would appreciate it firstly if you could advise me on radiology, please.

1. Is it safe to have an ultrasound on this over granulated or hypergranulated wound to check the underlying cause?
2. As we read on the internet, ultrasound is more appropriate to check a cyst. If it is safe to have an ultrasound on this current wound and around the scrotum, will ultrasound detect if there's a cyst formed? Or do we need to wait to have an ultrasound after the incision and drainage? If so, how many weeks should we wait?
3. Will an MRI show a cyst? Since ultrasound is a little bit cheaper here privately, and results would be available within an hour, we possibly can get it done. But we would like your advice on whether it's safe for this latest wound (picture attached).

We do not see any visibly cyst-type bump on his scrotum, but my son palpated the area, and he thinks something is there, and it is painful when he presses it. Should it be painful? We are a bit confused because some doctors told him that it was due to his hairiness, leading to the boil or infection. Only one doctor who saw the bump with an abscess told him it is a sebaceous cyst and required surgical removal. At that time, he prescribed Flucloxacillin to settle the infection, but the urologist performed incision and drainage due to him having three boil infections. My another queries are:

1. Can we apply Trimovate cream to that over granulated tissue? (Trimovate contains the following active ingredients: Clobetasone butyrate, calcium oxytetracycline, and Nystatin).
2. Upon observing the picture, do you think it is possibly a sebaceous cyst or could it be due to hair, resulting in a boil and subsequent infection? He sweats a lot; could there be a connection? He keeps the area clean, though.

He had several boils with abscesses about nine years ago on his buttock. At that time, pediatric doctors performed incision and drainage as the abscesses were severe. Back then, he was told that this issue was due to his hairiness, as my son is quite hairy. We recently shaved his scrotum with a shaving machine so we can keep an eye on it, and he is very scared, having gone through many incision and drainage procedures. After these procedures, the wound is very painful, and we have had to apply packing and proper dressing every day until it began over granulating. Some days, nurses did the dressing, and on others, we had to do it ourselves. We are eagerly awaiting your advice.

Hi doctor,

Thanks for your response.

If you could advise me bit more please. I would be appreciated.

1. My son had incision and drainage almost six weeks ago for the latest wound. I sent you some pictures in my previous post to show its current status. I was wondering, if it is a sebaceous cyst obviously, it will need surgical removal, which they have suggested here. My question is, how long do we need to wait to remove this cyst after the incision and drainage procedure? Will it regrow? Because we cannot see on the skin where the boil was infected. Is it deep down under the skin? (We saw sebaceous cysts on the scrotum on the internet, and they seem to be clearly visible on the skin) Short note: Urologist consultants examined his scrotum, around his wound after four weeks of his incision and drainage procedure. They pressed deep down to perform a physical examination, and they told him, 'There is a cyst inside, so once the MRI results come, we will surgically remove this cyst.'
2. My question is, should it be very deep down underneath the skin? We are a bit confused. As you can see on his scrotum, we only see his wound, not the cyst. So how will they be able to remove it?
3. Can acne on the face cause such boil-type infections in the scrotum area? He had a lot of acne on his face. In case by touching, he got a boil there, so I am asking for your opinion.
4. I totally understand that you have not seen this boil from the beginning, and you are not physically here to check, but looking at his infected boil picture. I am interested in knowing your firm opinion. Do you think it is a sebaceous cyst or a hair follicle infection? He had boils nine years ago, and I saw the same pattern and was told it was due to the hair.
5. As you know, with Flucloxacillin, his infection did not clear up, and the issue remained with an abscess. What could be the reason that Flucloxacillin did not help?

I am looking forward to your opinion and advice.