Hello, my name is***** and I have over 20 years of experience as a veterinarian.
I am very sorry to hear about your pup Lucy's inability to settle, stretching and extending her front legs and chest down with her rear end up in the air, and licking her paws and scratching her ears.
The front legs and chest down, rear end up in the air position is called a prayer bow and is often an indication of abdominal pain or cramping in a dog. It is a stretching motion attempting to relieve pressure/pain in the abdomen. With her other symptoms of itchy feet and ears I am highly suspicious of a food allergy or intolerance.
In some cases where the dog acts very uncomfortable it is possible that the pup is experiencing some reflux or abnormal motility, or painful intestinal spasms that are more than the usual. In severe cases this can be linked to pancreatitis which is a painful inflammation of the pancreas leading to increased enzyme leakage.
Other possible causes of nausea and abdominal pain include a sudden change in diet, or eating things that they should not like too many fatty table scraps or garbage, bones etc. Addison's which is a poorly functioning adrenal gland is another possibility for waxing and waning abdominal discomfort and nausea. Metabolic organ failures (kidney or liver disease), inflammatory bowel disease or even infiltrative cancers are possible causes as well.
Has she eaten anything she should not have recently (toy pieces, bones, garbage)?
Any changes in food or treats?
Food allergy is very possible with her as food allergic dogs often have very itchy ears and feet and may have abdominal cramping. Dogs can develop allergies to any protein or carbohydrate so even if she is only fed one thing that can be what she is allergic to. Dogs with food allergies tend to lick and scratch their paws, face and ears the most, but any of the "allergy reactive areas" can be affected. You could try a true hypoallergenic diet like Hills z/d or Purina Veterinary Diets HA. No treats, flavored medication or bones while on the diet and it must be used for a least 12 to 16 weeks to see the full effects. Most clients do report some improvement in 4 to 6 weeks.
Over the counter foods may be labeled hypoallergenic but they are unlikely to truly be so.
The trouble with "limited ingredient", "hypoallergenic" or "low allergy" pet store brands is that the same machinery is used on multiple lots of food without sterilization cleaning in between. So for example even if a food says it has salmon and rice if the previous batch had beef and corn then you will get traces of those ingredients in your bag of food. Not a big deal if your dog isn't allergic to those ingredients but a waste of money thinking that the food was hypoallergenic, and not good for your dog if those happen to be allergens for your dog.
The veterinary brand true hypoallergenic foods are more expensive because it isn't cheap to thoroughly remove all traces of a previous food mixture from the machines used to process food or to hydrolyze the proteins in the food. And the only ingredients in that food, even at a trace level, are what is listed on the bag.
Even though some pet food companies may try to convince you otherwise there are no magic hypoallergenic food ingredients. A food allergy reaction is based upon the dog's body recognizing an allergen, so they must have been exposed to it before. Prescription foods are hydrolyzed, or broken down so the body cannot recognize the allergen, or use very unusual ingredients that the dog cannot have been exposed to in the past. They cannot develop an allergy to something they have never been exposed to.
In the meantime today to try and get her feeling better you can give her acid reducers to try and settle her stomach. Either:
1) Pepcid-ac (famotidine) at a dose of one half of a 10mg tablet per 10 to 20 pounds of body weight every 12 hours.
2) Prilosec (omeprazole) at a dose of one half of a 10mg tablet per 10 to 20 pounds of body weight every 24 hours.
These will reduce stomach acid and should help settle her stomach. These can be used long term if necessary as they are very safe.
I'd also pick up her food and water for now. A couple hours after one of the acid reducers you can offer small amounts of water or ice cubes to lick.
No food for 12 hours. Small amounts of water only.
After her food fast then start a bland diet of 1/3 boiled, lean hamburger (or boiled, white, skinless chicken) and 2/3 boiled white rice. Give small meals several times a day. Feed the bland diet for several days, then start mixing in her regular diet or a hypoallergenic food and slowly convert her to the diet.
If her nausea and abdominal pain continues then she may need injectable medication from her veterinarian to get her stomach upset under control.
So watch her for continued symptoms even with the acid reducers, blood in her stool or vomit or a fever (more than 103.5F rectally), a tense painful belly or lack of appetite after her food fast. If any of those occur it is time to seek hands on veterinary care.
If this has been a repeated problem for her consider whether she has been getting different treats or lots of table food, or have you been feeding a different diet?
If you choose not to try a hypoallergenic diet right away and go back to the original food, stop table food and treats and her nausea and itchy feet and ears continues even with the acid reducers, fast and bland diet then you may wish to consider using a using a true hypoallergenic food such as Hills z/d or Purina Veterinary Diets HA long term. She may have a dietary allergy or a sensitive stomach. It would also be a good idea to have blood tests done as well to make sure there isn't an underlying metabolic problem like early organ failure, pancreatitis or Addison's disease present.
Please let me know if you have any further questions.