Part Siamese female bobtail and some bob tailed offspring developed sores

We rescued a bob tailed Siamese female,, her daughter and their offspring about a year ago. The poor Siamese had bumps on her body about the size of pencil erasers which would erupt into red sores. Cortisone seemed to help temporiarily but they never completely went away. They always returned after a few weeks.

We only found all bob tailed males and a few tabby tailed males. No female bob tails among the 11 offspring. We trapped, spayed/neutered them all

We adopted out all the offspring except her daughter a tailed calico, a tailed male tabby and a bob tailed male.

The cats are now approaching a year old and the little bob tailed male is beginning to show the sores! Her grown tailed daughter and the brother to the bobtail (a tabby male) do not show the bumps.

We have no knowledge of the other adopted bob tails condition. The Siamese mother was given to a Siamese rescue group in Kansas City.

Has anybody ever heard of such a condition?

It just breaks my heart to see this happening to the little bob tailed male we named Morty. The mother seemed to suffer so with the sores.

I don't suspect allergy because the mother had them when we rescued her and Morty was a year old living in our basement before he started developing them.

Did you never take either of these two (with the eruptions) to the Vet to see what they might be?

I've never heard of anything the way you describe it, but maybe someone else will come along and know something. 

We took our sweet Sassy, the part Siamese just shortly after we trapped her. The vet said it looked like either fleas or allergy. She promptly gave her a cortisone shot which temporarily helped. Vets around here are mostly like the doctors... Easier to treat the symptoms than find the cause. We had Sassy about 3 months before we found the Siamese cat rescue up in Kansas City... Great people if you have a Siamese.

Morty has just started to develop the bumps/sores... Just a few. He is an inside cat and appears unaffected by them where Sassy just scratched all the time.

He will be going to the vet shortly.

Thanks for your concern.

Just a sidebar that speaks volumes for neuter/spay. About 2 years ago Sassy came to my brother-in-law's house. We helped trap her but the vet said she was too young to fix. After that brother turned her loose and she disappeared (we are in a rural farming area). She was around off and on until about a year ago when she showed up at his house with her daughter, four kittens, the daughters four kittens and two feral males!!!
They don't share our belief in TNR so they did not feed them and they disappeared. My wife and I began to canvas the old houses, barns and farms in the area. After several weeks we found them all up the road at a renters delapidated farm house living under his stone porch steps. He fed them , which is rare for our area, but just a Walmart kibble. We set about the TNR finally trapping them all and placing all but the 2 feral males. We ended up keeping the daughter (a calico tailed), a tabby male also tailed called tigger and Morty, the bob tailed little male. This added to our other four rescues living with us and the eight other rescues in the TNR colony we feed.

Spay and neuter!!!!