Thank you for the prompt reply.
The scenario that you describe is very common and I see cases like this, of varying degree, on a weekly basis. It is now believed that if a cat has a normal GI tract, they should be able to pass the hair that they are ingesting while grooming without a problem. We used to think that hairballs led to vomiting, but we now believe that hairballs are a sign of an unhealthy GI tract. There are various things that can affect the GI tract and cause it to not function as efficiently as it should and lead to symptoms such as vomiting or decreased appetite.
Vomiting is a vague sign that can be associated with simple things like dietary indiscretion to more serious things like intestinal obstruction or metabolic disorders. In young cats, we usually are a little more worried about foreign body ingestion. We decide how aggressive we need to be in diagnosing and treating it based on how severe the symptoms and how long it has been going on.
In her case, I would be concerned in that it is going on without resolution for so long. It definitely warrants at least an exam and probably some bloodwork or xrays. The exam may help to rule out obvious things like intestinal masses, but bloodwork is needed to rule out metabolic changes like diabetes, thyroid or kidney disease. Xrays will help to rule out an obstruction. It is not uncommon for all of these tests to be normal and there can still be GI disease present. Inflammatory bowel disease (IBD) is a very common cause of vomiting in cats. If your vet suspects this, they may offer a trial of medication or a change in diet to see how she responds. When there is an irritated GI tract, for whatever reason, there may be foods that are better tolerated than other and wet food is often more so than dry food. The fact that the vomiting of has increased is reason enough to pursue a diagnosis.
I hope this is helpful. Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please reply so I can clarify for you.
My posted replies are for general education only and not meant as a diagnosis. Only after a thorough veterinary examination can a diagnosis for your pet be made and specific treatments be advised or medications be prescribed.