Scabby flakey skin on my cat

Question
My cat Sissy is nine years old, we have had her since she was 8 weeks old. She is an indoor/outdoor cat and spends time in and outdoors 50/50 we live in the country and she comes and goes as she pleases, she is potty trained and doesn't use or even have a litter box. A few weeks ago my husband noticed that she had some scabbing and reddish colored spots on her lower back just above her tail. Tonight I noticed she now has scabs and flaking skin all over her body, everywhere except for her tummy. The scabs are a reddish color but aren't bleeding and don't seem to be causing her pain. At first I thought fleas but there is no evidence of fleas or flea eggs, she has never had a problem with fleas in the past and therefore we really don't treat for fleas. I've read that it could be mites or ringworm. I'd like to know what it might be and more importantly if it is something that can be passed to humans, we have two small children and she is often in their rooms and beds, she also gets in our bed from time to time but not as much since the dogs sleep in our room. Can these sorts if things be passed to humans and dogs? Are there any home remedies? I saw someone suggested an oatmeal bath another person said diluted vinegar. She doesn't like water and hasn't had a bath in years. She has never had anything like this in her life and he has always been indoor/outdoor. Any advise or suggestions are welcome, I know she should probably be taken to the vet but money is so tight I thought I'd explore the options and try home remedies first. Could it have anything to do with cold weather? Please help!

Answer
These scabby areas are consistent with some type of allergy.  Yes, flea allergy will do that, but allergies to many other environments allergens will cause the exact same lesions.  In some cases, an antihistamine will help reduce these lesions, but in many cases a shot of a long acting steroid called DepoMedrol is usually indicated to decrease the cat's skin reaction to allergens.  This shot lasts about 4-6 weeks, which gives the skin plenty of time to heal.  Some cats are food allergic and so a diet change to a food consisting of different protein source ingredients than she is eating now may help.  In other words, if she is on a chicken based diet, try a beef based one or a soy one.