Mites and Mysterious growth on the back at the bottom of spine

Question
Hi, my piggy has been sick.  We have taken him for two treatments of ivermectin (sp?) for mites.  After his first treatment he was also given an antibiotic.  We had to take him back to the vet the next week to get another shot of the ivermectin.  I noticed a huge lump at the bottom of where it seems his spine ends almost, its about an inch in diameter and its raised about a 1/4 inch and hard.  It hurts him when you press on it.  I asked the vet what is was and she said she wasn't sure, but I could have it biopsied which would cost me 150.00.  I would never put a price on my piggy, but I cant afford that beings I am pregnant and out of work right now.  Do you have any idea what it could possibly be? I find it weird that it didnt appear until he got put on the antibiotics.  Also he is still itching after his second does of ivermectin, which was 7 days ago today.  I dont want my piggy to be in pain, but unfortunately I cant pay that type of money right now to find out what the lump is, and honestly cant afford another office visit for another shot.  Should I give this second shot more time to work and do you have any idea about the lump on his spine/back  =(  Thank you

Answer
Hello Shera,

Ok, first is the lump movable or does it feel like it is attached? If it moves it could be a cyst or an abscess. Abscesses are pockets of infection that are typically warm to the touch and generally quite painful. Abscesses are found anywhere on the body. Treatment is lancing, draining, antibiotics, and/or surgical removal. Sebeceous cysts are relatively harmless. They are similar to a pimple in humans. They can be painful because of built up pressure and depending on location but usually the pain isn't too bad. Cysts can be found anywhere but are most common on the piggy's hind quarters. Treatment is lancing, draining, flushing, surgical removal, or waiting until it bursts and then flushing daily until it heals. If it doesn't move, it's possibly a tumor and surgery is really the only option. However, there is one more possiblity, since he is a male and because of the location. This one is entirely harmless and would be the one I'd check for first. There is a grease gland at the base of a boar's spine right where his tail would be if he had one. Some boars will have one that produces a bit too much and causes a hard waxy build up that can be a bit sensitive. Try taking a soft bristle toothbrush and baby oil to it. Gently scrub at it a bit. If an orangish yellow waxy substance begins coming off, that's all it is. He will require this treatment fairly regularly as part of his regular grooming, but it is normal and he's perfectly healthy. Based on the location, this is most likely the case, so hopefully that's all it is any your piggy will be just fine. As for the mites, usually there is a significant change after the first dose. You can wait 10 days before another treatment to see if it has helped. Is your vet certain it is mites and not something else? Fungal infections can have similar symptoms. If you are certain it is mites, it is best to get the shot if you can at all afford it. Mites can be extremely painful and itchy. Also, if the lump does turn out to be an overproduction of his grease gland, if possible, you may want to seek out another vet for his care. It's possible your vet, though possibly a wonderful vet, isn't too familiar with piggies and if that's the case, he may get better care elsewhere. Good luck. I'll keep your piggy in my prayers. Congratulations and good luck with your pregnancy.

-kkat
http://www.geocities.com/abyssinianguineapigs