Experienced and professional animal trainer provide their insights in answering this question :
A. Lethargy can be due to age, weather, fever and just about any illness. If it continues for 48hours or there are any other symptoms then see your vet for a check up.

How to Identify Common Pet Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced pet care professionals :

Infections, illnesses, and pain can make your dog tired, listless and uninterested in food. When these symptoms continue for more than 24 hours, they could indicate the presence of a health issue that requires a visit to our veterinary hospital in Diamond Bar.
A lethargic dog is not interested in his/her normal day-to-day life and is either unable or unwilling to get up out of bed very often. He/she may be weak and unable to move well, or he may be stiff and in a lot of pain when he/she moves.
So, it is normal for your dog to sleep or rest for a majority of the day. However, excessive sleep can be concerning for any pet owner. If your dog is sleeping too much, this could indicate health issues, such as canine depression, diabetes and hypothyroidism, says the AKC.
There are a few reasons a dog may become quieter than usual: pain, stress, or boredom. While a quieter dog may not feel like such a “problem” to us, it`s important to make sure their behavior change isn`t a sign of a bigger medical or behavioral issue.
Some of the signs of parvovirus include lethargy; loss of appetite; abdominal pain and bloating; fever or low body temperature (hypothermia); vomiting; and severe, often bloody, diarrhea. Persistent vomiting and diarrhea can cause rapid dehydration, and damage to the intestines and immune system can cause septic shock.
When should I be concerned about my dog being lethargic? You should be concerned if your dog has shown signs of lethargy for more than a day. This may be an indicator that your dog is suffering from an illness, so you should visit a vet to get a proper diagnosis if symptoms persist for more than 24 hours.
Lethargy, sleepiness, not moving much

Pay attention to how much your dog normally moves and sleeps. If you notice that suddenly your dog is not moving much or is more “lazy” than usual, it might be a sign you have a sick dog. Dogs in pain will typically be less active than healthy dogs.

If your pup is disappearing or withdrawing to odd places in the home, they could be feeling stressed or sad. “You may find them sleeping under the bed or in a closet. This is a common sign seen with depressed dogs,” says Ochoa. Try playing a game or giving them more attention to make them feel happier and more relaxed.
His bed is too small, lumpy, or dirty and he feels claustrophobic or uncomfortable in it. You`ve recently moved his bed and he doesn`t like the new location. He`s too hot and is trying to regulate his body temperature by lying on a cool tile or wood surface. Or he might be searching for a less drafty sleeping spot.
You can try offering your dog some of their favorite treats or a small amount of cooked chicken or hamburger. If the problem lasts more than a day or is associated with other symptoms like lethargy, vomiting, and weakness, the best course of action is to see your vet.
A good diet is key to preventing lethargy in dogs of all ages. The best dog food for lethargy should contain quality protein and dietary fibre to provide energy, as well as some complex-carbohydrates that provide slow-releasing energy.
The scent generally associated with parvo is caused by blood in the stool. Dogs with bloody stools because of hookworms have precisely the same smell. MORE IMPORTANTLY, if a puppy is diagnosed with Parvo BEFORE there is blood in the stool, the antivirals` effectiveness is MUCH GREATER.
Fifth disease is a mild rash illness caused by parvovirus B19. It is more common in children than adults. A person usually gets sick with fifth disease within 14 days after getting infected with parvovirus B19.
Symptoms caused by swallowed poisons can include: vomiting, diarrhoea, agitation and heart issues. Inhaled toxins may cause breathing difficulties or loss of consciousness in dogs. If your dog`s skin comes in contact with a poisonous substance typical symptoms include irritation and pain.
Generally, the symptoms of food poisoning in dogs include some combination of vomiting, diarrhea, reduced appetite, lethargy and dehydration. Some animals may show some neurological signs such as a lack of coordination, tremors and, in severe cases, even seizures and collapse.
Lethargy is a sign that something may be troubling your dog. A lethargic dog may be uninterested in playing, going for a walk, or participating in activities they usually enjoy. Normal fatigue or sore muscles can sometimes be due to high temperatures, but you should see a vet if symptoms persist for more than two days.
It might be allergic rhinitis, anemia, depression, fibromyalgia, chronic kidney disease, liver disease, lung disease (COPD), a bacterial or viral infection, or some other health condition. If that`s the case, then the long-term outlook is good. Here are some common causes of fatigue and how they are resolved.
Symptoms of SARS-CoV-2 infection in pets

Most pets who have gotten sick only had mild illness and fully recovered. Some signs of illness in pets may include fever, coughing, difficulty breathing or shortness of breath, lethargy, sneezing, nose or eye discharge, vomiting, or diarrhea.

Lethargy doesn`t necessarily affect a dog`s appetite unless there are other symptoms like vomiting or diarrhea. “You can be really lethargic, but still maintain your appetite and have normal water drinking,” Dr. Attas says.
Little or negative socialization

You might find your dog become aggressive, shy, or fearful around other humans or animals. Lack of socialization may even cause depression spells. You may witness your dog develop irregular sleeping and eating patterns, or it may refuse to play.

Just like us, dogs can have days when they are down in the dumps. They may be lethargic, less willing to play than usual and may even ignore you when you call them. If this goes on for longer than 24 hours, it`s possible they`re not just having an `off` day and may be depressed.
Do Dogs Need Soft Beds? Dogs don`t need soft beds, but instead need to rest on a firm surface; too-soft pillow beds don`t offer the support needed for comfortable rest and healthy joints, and an older dog who sinks into a plush bed may have trouble getting into and out of it.
Your scent is familiar, so your dog knows instinctively that any place you`ve been must be familiar and safe, too. It`s the same reason why dogs are keen to sleep in our beds, ride in our cars, and lounge on our furniture and in our laps.
When your dog turns his back to you, he is showing you that he`s friendly and trusts you. In the animal world, turning your back to someone puts you in a vulnerable position. Your dog is trusting that you won`t attack him from behind.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. What could be causing my dogs hair to fall out causing bald spots?
ANSWER : A. Skin problems can have a variety of causes, sometimes more than one. It is important to have the problem checked by your vet to determine if there is a medical cause for your pet’s skin issues and treat accordingly.

In pets of all ages, fleas, food allergies and exposure to chemical irritants such as cleaners and soaps can be a cause. Any one of these may not be enough to trigger the breakouts, depending on how sensitive your pet is, but a combination can be enough to start the itch-scratch cycle. Finding out the cause and eliminating it is the best course of action. With flea allergies, if your pet is sensitive enough, a single bite can cause them to break out scratch enough to tear their skin.

Check for fleas with a flea comb. Look for fleas and/or tiny black granules, like coarse black pepper. This is flea feces, consisting of digested, dried blood. You may find tiny white particles, like salt, which are the flea eggs. Applying a good topical monthly flea treatment and aggressively treating your house and yard will help break the flea life cycle.

If you use plastic bowls, this is a possible cause for hair loss, though this tends to be on the chin, where their skin touches the bowl while they eat. If you suspect this to be the culprit, try changing the bowls to glass, metal or ceramic.

Food allergies are often caused by sensitivity to a protein in the food. Hill’s Science Diet offers some non-prescription options for sensitive skin as well as prescription hypoallergenic foods for more severe cases. Royal Canin carries limited protein diets that may also offer some relief. Your vet can recommend a specific diet that will help.

If there is no relief or not enough, consider getting your pet checked by a veterinary dermatologist and having allergy testing done.

Q. Which common foods are poisonous to pets?
ANSWER : A. That’s a great question. As responsible pet owners we need to be aware of food items that can be harmful to our canine or feline companions. Here are some of the most common foods proven to cause illness in our animals at home:

Chocolate: A favorite and irresistible treat amongst most humans, chocolate is considered toxic to dogs. In very small amounts it is usually not a huge issue, but with larger volumes and with darker chocolates pet owners should be concerned. Chocolate contains methylxanthine theobromine, which is similar to caffeine. Chocolate ingestion can cause vomiting, diarrhea, hyperactivity, issues with normal heartbeats, seizures, and in some severe cases, death. It is best to keep your favorite chocolate treats in a good hiding spot and out of reach of your dog or cat.

Grapes and raisins: Dogs should not consume grapes and raisins because of the risk of acute kidney failure. Most dogs experiencing grape or raisin toxicity will begin to have vomiting and/or diarrhea within 6-12 hours of ingestion. Other abnormal clinical signs include lethargy, abdominal pain, dehydration, and tremors. Kidney failure develops within 24-72 hours of the initial ingestion. There are some dogs that do not experience these devastating side effects. It is best to contact your veterinarian or veterinary emergency facility if you believe your pet has ingested grapes or raisins.

Garlic and onions: We often forget that our meals contain these two popular ingredients and will allow our furry companions a few bites or licks. Onion and garlic both can cause a type of poisoning that results in damage to red blood cells, making them more likely to rupture. They can also cause stomach upset and mouth irritation. Look for pale gums, increased breathing or drooling or any vomiting or diarrhea.

Bread dough: Unbaked bread dough is considered poisonous to our pets. The bread dough, when ingested, expands in the stomach because of the warm and moist environment. This can lead to a bloated or even twisted stomach. In addition yeast is often added to our baking products to help get bread to rise, and when this yeast is fermented it produces both carbon dioxide and alcohol. The alcohol produced can be absorbed into the bloodstream and causes dangerous drops in blood sugar, blood pressure and body temperature. Common clinical signs include vomiting or retching, distension of the stomach, weakness and collapse.

Macadamia nuts: Ingestion of these nuts are not proven to be fatal in dogs but can cause them to experience uncomfortable clinical sings, including fever, joint stiffness, vomiting, tremors and difficulty walking, especially in their hind legs. Often your pet will start to feel better after about 48 hours, but supportive veterinary care (such as pain medication) may help ease their discomfort.

Xylitol: The most common ingredient used in sugar-free gum is xylitol, which is a non-caloric sweetener. It is also found in some oral rinses, toothpastes and vitamins. Xylitol and dogs do not mix – it can cause a dangerous drop in blood sugars levels. Dogs will often display signs of disorientation, black tarry stool, tremors and seizures. If severe enough some dogs have developed liver failure. Keep your gum away from your canine companion.

Avocados: Avocados are not actually poisonous to dogs or cats but as many veterinarians can tell you the avocado pits can cause a foreign body obstruction. Avocados contain persin, which is actually toxic to the majority of pet birds. The abnormal clinical signs associated with avocado ingestion in birds include, respiratory distress, inability to perch, liver and kidney failure and sudden death.

Go forth and enjoy your favorite foods, but keep in mind which foods you should avoid sharing with your furry family members. Whenever in doubt, contact your veterinarian for healthy and safe food suggestions.

Q. He is not eating or drinking seems like he has no energy and vomiting and seems like he weak
ANSWER : A. Causes of not eating and vomiting can be many. Gastrointestinal infection, caused by bacteria (salmonella, for example) or viruses or parasites (although parasite infections tend to be more mild, but giardia can make them feel pretty bad) can be a cause. Eating something he shouldn’t have, like the trash or rotten food can cause it. Intestinal obstruction can cause vomiting as well. Other causes (non-GI) of vomiting include kidney failure (can be due to many things, such as toxins, kidney stones, cancer) or liver diseases or liver failure.

The vomiting is concerning, however the weakness and lack of energy implies that he’s either seriously dehydrated or there’s a lot more going on than just s simple case of vomiting. He needs to see a vet and have testing, likely to include x-rays and/or blood work, to see what’s going on, so that it can be treated.

Q. My frenchie puppy has a rash in her ears and one of her eyes is red
ANSWER : A. Skin problems can have a variety of causes, sometimes more than one. It is important to have the problem checked by your vet to determine if there is a medical cause for your pet’s skin issues and treat accordingly.

In pets of all ages, fleas, food allergies and exposure to chemical irritants such as cleaners and soaps can be a cause. Any one of these may not be enough to trigger the breakouts, depending on how sensitive your pet is, but a combination can be enough to start the itch-scratch cycle. Finding out the cause and eliminating it is the best course of action. With flea allergies, if your pet is sensitive enough, a single bite can cause them to break out scratch enough to tear their skin.

Check for fleas with a flea comb. Look for fleas and/or tiny black granules, like coarse black pepper. This is flea feces, consisting of digested, dried blood. You may find tiny white particles, like salt, which are the flea eggs. Applying a good topical monthly flea treatment and aggressively treating your house and yard will help break the flea life cycle.

If you use plastic bowls, this is a possible cause for hair loss, though this tends to be on the chin, where their skin touches the bowl while they eat. If you suspect this to be the culprit, try changing the bowls to glass, metal or ceramic.

Food allergies are often caused by sensitivity to a protein in the food. Hill’s Science Diet offers some non-prescription options for sensitive skin as well as prescription hypoallergenic foods for more severe cases. Royal Canin carries limited protein diets that may also offer some relief. Your vet can recommend a specific diet that will help.

If there is no relief or not enough, consider getting your pet checked by a veterinary dermatologist and having allergy testing done.

Q. My dogs skin has become red the vet said its an allergy to fleas yet he has none could it be an allergic reaction to my new carpet.
ANSWER : A. Skin problems can have a variety of causes, sometimes more than one. It is important to have the problem checked by your vet to determine if there is a medical cause for your pet’s skin issues and treat accordingly.

In pets of all ages, fleas, food allergies and exposure to chemical irritants such as cleaners and soaps can be a cause. Any one of these may not be enough to trigger the breakouts, depending on how sensitive your pet is, but a combination can be enough to start the itch-scratch cycle. Finding out the cause and eliminating it is the best course of action. With flea allergies, if your pet is sensitive enough, a single bite can cause them to break out scratch enough to tear their skin.

Check for fleas with a flea comb. Look for fleas and/or tiny black granules, like coarse black pepper. This is flea feces, consisting of digested, dried blood. You may find tiny white particles, like salt, which are the flea eggs. Applying a good topical monthly flea treatment and aggressively treating your house and yard will help break the flea life cycle.

If you use plastic bowls, this is a possible cause for hair loss, though this tends to be on the chin, where their skin touches the bowl while they eat. If you suspect this to be the culprit, try changing the bowls to glass, metal or ceramic.

Food allergies are often caused by sensitivity to a protein in the food. Hill’s Science Diet offers some non-prescription options for sensitive skin as well as prescription hypoallergenic foods for more severe cases. Royal Canin carries limited protein diets that may also offer some relief. Your vet can recommend a specific diet that will help.

If there is no relief or not enough, consider getting your pet checked by a veterinary dermatologist and having allergy testing done.

Q. My staff dog loosening her hair down side of her head
ANSWER : A. Skin problems can have a variety of causes, sometimes more than one. It is important to have the problem checked by your vet to determine if there is a medical cause for your pet’s skin issues and treat accordingly.

In pets of all ages, fleas, food allergies and exposure to chemical irritants such as cleaners and soaps can be a cause. Any one of these may not be enough to trigger the breakouts, depending on how sensitive your pet is, but a combination can be enough to start the itch-scratch cycle. Finding out the cause and eliminating it is the best course of action. With flea allergies, if your pet is sensitive enough, a single bite can cause them to break out scratch enough to tear their skin.

Check for fleas with a flea comb. Look for fleas and/or tiny black granules, like coarse black pepper. This is flea feces, consisting of digested, dried blood. You may find tiny white particles, like salt, which are the flea eggs. Applying a good topical monthly flea treatment and aggressively treating your house and yard will help break the flea life cycle.

If you use plastic bowls, this is a possible cause for hair loss, though this tends to be on the chin, where their skin touches the bowl while they eat. If you suspect this to be the culprit, try changing the bowls to glass, metal or ceramic.

Food allergies are often caused by sensitivity to a protein in the food. Hill’s Science Diet offers some non-prescription options for sensitive skin as well as prescription hypoallergenic foods for more severe cases. Royal Canin carries limited protein diets that may also offer some relief. Your vet can recommend a specific diet that will help.

If there is no relief or not enough, consider getting your pet checked by a veterinary dermatologist and having allergy testing done.

Q. Year 3 my dog loses patches of hair on back, stomach and neck. Vet has tested, but has not found anything. Patches are a red and scaly by hair lin
ANSWER : A. Skin problems can have a variety of causes, sometimes more than one. It is important to have the problem checked by your vet to determine if there is a medical cause for your pet’s skin issues and treat accordingly.

In pets of all ages, fleas, food allergies and exposure to chemical irritants such as cleaners and soaps can be a cause. Any one of these may not be enough to trigger the breakouts, depending on how sensitive your pet is, but a combination can be enough to start the itch-scratch cycle. Finding out the cause and eliminating it is the best course of action. With flea allergies, if your pet is sensitive enough, a single bite can cause them to break out scratch enough to tear their skin.

Check for fleas with a flea comb. Look for fleas and/or tiny black granules, like coarse black pepper. This is flea feces, consisting of digested, dried blood. You may find tiny white particles, like salt, which are the flea eggs. Applying a good topical monthly flea treatment and aggressively treating your house and yard will help break the flea life cycle.

If you use plastic bowls, this is a possible cause for hair loss, though this tends to be on the chin, where their skin touches the bowl while they eat. If you suspect this to be the culprit, try changing the bowls to glass, metal or ceramic.

Food allergies are often caused by sensitivity to a protein in the food. Hill’s Science Diet offers some non-prescription options for sensitive skin as well as prescription hypoallergenic foods for more severe cases. Royal Canin carries limited protein diets that may also offer some relief. Your vet can recommend a specific diet that will help.

If there is no relief or not enough, consider getting your pet checked by a veterinary dermatologist and having allergy testing done.

Q. My 10 year old male German Shepard Dog is constantly chewing at his legs, hind quarters and underbelly. No fleas or visible rash. Inside dog. Any ide
ANSWER : A. Skin problems can have a variety of causes, sometimes more than one. It is important to have the problem checked by your vet to determine if there is a medical cause for your pet’s skin issues and treat accordingly.

In pets of all ages, fleas, food allergies and exposure to chemical irritants such as cleaners and soaps can be a cause. Any one of these may not be enough to trigger the breakouts, depending on how sensitive your pet is, but a combination can be enough to start the itch-scratch cycle. Finding out the cause and eliminating it is the best course of action. With flea allergies, if your pet is sensitive enough, a single bite can cause them to break out scratch enough to tear their skin.

Check for fleas with a flea comb. Look for fleas and/or tiny black granules, like coarse black pepper. This is flea feces, consisting of digested, dried blood. You may find tiny white particles, like salt, which are the flea eggs. Applying a good topical monthly flea treatment and aggressively treating your house and yard will help break the flea life cycle.

If you use plastic bowls, this is a possible cause for hair loss, though this tends to be on the chin, where their skin touches the bowl while they eat. If you suspect this to be the culprit, try changing the bowls to glass, metal or ceramic.

Food allergies are often caused by sensitivity to a protein in the food. Hill’s Science Diet offers some non-prescription options for sensitive skin as well as prescription hypoallergenic foods for more severe cases. Royal Canin carries limited protein diets that may also offer some relief. Your vet can recommend a specific diet that will help.