Our Dog Has Been Vomiting Yellow Frothy Stuff, Has Several Tiny Patches Of Hair Loss And Is Eating Grass Now. Please Advise. Would The Tiny Hair Loss Patches And Vomiting Be Related To A Tick Infestation?

Vomiting in dogs can be due to

1. Side effects of medicines
2. GI tract obstruction
3. Inflammatory bowel disease
4. Inflammation of GI tract
5. Parvovirus
6. Parasites
7. many diseases like cancer, liver and kidney failure.
   

I your case it can be the spray or medicines which you have used to eliminate ticks or eye infection. The ticks are related with hair loss in dogs because they cause itching and dog lick the affected area leading to hair loss.  A steroid therapy can work if there are no wounds.