Skin issues with guinea pigs

Question
Hello,
I have 6 great guinea pigs. 5 of them are from the same family. I adopted a female for my neutered elderly guinea pig "Ozzie and shortly found out she was expecting 4 babies. I have the 2 boys in a separate cage from the 3 females and my neutered male. During this last winter season they had no skin issues. During this time (summer) I have noticed that the mama, one of her sons and one of her daughters has acquired this skin issue. It seems as if they are experiencing a skin irritation. They have started to get mild bald spots at the site. They also have scabs I believe from biting at themselves. The area is also a little red. This irritation affects their middle of their backs and their butts. I bathe them every 1-2 months with tearless shampoo designed for small animals. The mother is an american shorthair. 2 of her babies came out american shorthair(they have no skin issues). The other 2 on the other hand have very coarse wirey hair. They are the only ones with this skin issues. I am not sure if it is the summer heat that gets to them or maybe a genetic defect. When the mama was dropped off at the shelter she was brought in with 3 other males(one that looked just like her) and I suspect if not all some of those males may have been related to her. One male had wirey like hair but not as wirey as my like guys. I have frequently checked their eyes, noses, mouth, ears and fur for any parasites/illnesses. All 6 are healthy. They interact normal and respond to when I feed them and give them water normal. They do not have any parasites. I have had a rat before with mites and the scabs my guineas have do not look the same as what my rat had. I also tried them on different bedding and they still have the skin irritation. Even with using carefresh. Could they be having hot spots due to the summer season? Is it maybe summer season allergies?

Answer
Well you did the right thing by changing the bedding to see if it was an allergy. Since that did not work have you tried changing food. Maybe it is a food allergies to the pellets that you feed them. Another option is making sure they have vitamin C in their water of with oranges every other day so they dont have a deficiency.

I had 3 guinea pigs that had this same issue and when we went to the vet she gave us some antibiotics for a skin infection that we gave daily. I have also heard to using a fungal cream on the areas to get rid of the irritation. My suggestion would be to see a vet to make sure. It could be a parasite under the skin or something of that matter. I dont believe it has to do with weather because we have guinea pigs here dealing with Florida heat and have not issues and they are of all breeds.

More websites that may help:

http://www.peteducation.com/article.cfm?c=18+1800&aid=2998

http://www.associatedcontent.com/article/2047041/guinea_pigs_and_skin_problems.h...