Experienced and professional animal trainer provide their insights in answering this question :
A. It sounds like it is an allergic reaction. If they don’t start to go down in a few hours, get worse or the dog has any other symptoms then you should see your vet as soon as possible.

How to Identify Common Pet Problems ?

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

Histiocytomas are an abnormal growth of immune cells in the skin, and are often seen on young dogs. These masses can look angry, because of their bright red color and “bubbled” surface. They often appear overnight and sometimes will disappear without treatment.
There are several reasons why your dog may develop bumps and lumps. It can be a benign growth, skin infection, allergic reaction, or something more serious like cancerous tumors. Consult with your vet to get an official diagnosis and treatment plan.
Sometimes lumps can appear on dogs overnight — if they don`t seem to bother your pet, you can monitor the growth at home until your next vet visit. But, if your dog starts licking or scratching the bump, or it changes in appearance, contact your vet as soon as possible.
Can lipomas in dogs grow fast? Lipomas are traditionally slow-growing tumors. If you find a mass that seems to have appeared overnight, it is unlikely to be a lipoma.
If the mass isn`t painful, red, irritated or giving off a strong odor, you are likely not dealing with an emergency. Still, you should schedule an appointment soon to have your pet evaluated. Since some pet lumps and bumps are cancerous, it is important to have your pet evaluated as soon as possible.
While some may be present for many months without growing much, others can appear suddenly and grow very quickly. Sometimes they can suddenly grow quickly after months of no change. They may appear to fluctuate in size, getting larger or smaller even daily.
Sometimes, dogs will develop an obsessive habit of licking themselves to such a point that they cause trauma or lesions on the skin. This is often brought on by stress, anxiety, or boredom. The lesions that result tend to red, well-rounded, and raised bumps.
Unless you`re sure about the cause of a lump or bump, bring your dog in for an exam. If you see fast growth, redness, swelling, pus, an opening, or if the dog is in pain, make that appointment even sooner.
Cancerous lumps are hard and painless. They might seem to appear overnight and grow with time. A cancerous lump may block your windpipe or create pressure in the throat or nose. See your provider immediately if you notice these kinds of symptoms.
Cancerous Tumors – A cancerous tumor will usually be harder than a lipoma, and won`t be hot or sensitive to the touch. The tumor may also be benign, in which case your dog`s health won`t be jeopardized by this tumor. However, a biopsy should be done to evaluate the tumor and determine whether treatment is necessary.
Considerations. Most lumps and swellings are benign (not cancerous) and are harmless, especially the kind that feel soft and roll easily under the fingers (such as lipomas and cysts). A lump or swelling that appears suddenly (over 24 to 48 hours) and is painful is usually caused by an injury or an infection.
Mast cell tumors can seem like lipomas until their cells are examined under a microscope. Hemangiopericytomas (a type of tumor related to blood vessel capillaries) can mimic the rubbery texture of a lipoma under the skin.
Every lipoma is different; some may grow rapidly and some may take years to grow large enough to be of concern. “…these tumors may continue to grow and cause your pet discomfort if not removed.”
It is recommended that pet owners take note of pet lumps and bumps when first observed. If it is larger than a pea and sticks around for a month or more, it`s time to figure out what`s going on. While they can definitely be harmless, it`s a good idea to keep ahead of pet lumps and bumps.
They rarely cause discomfort unless they are large.” They rarely cause discomfort unless they are large. Ulceration and bleeding are rare but large lipomas may necrose (die), causing yellow discoloration of the fat with, in the case of very large ones, toxic effects to make the animal unwell.
They may grow quickly, over the course of a few weeks. More commonly they grow slowly over months or years. In advanced cases, the skin overlying the tumor can ulcerate or break open. This leaves dogs susceptible to pain and infection.
Stomach tumors usually grow from the cells of the inner lining of the stomach or muscle that surrounds the lining. Stomach tumors may be either benign (non-cancerous) or malignant (cancerous). Malignant tumors are invasive and prone to metastasize (spread to other areas of the body).
Your veterinarian will be suspicious of an infiltrative liposarcoma if the fine needle aspirate cytology reveals fat cells, yet the tumor feels fixed to underlying tissues. (Lipomas are normally freely moveable.)
Lipomas often show up after an injury, though doctors don`t know whether that`s what makes them form. Inherited conditions can bring them on. Some people who have a rare condition known as Madelung`s disease can get them. This most often affects men of Mediterranean ancestry who have alcohol use disorder.
Your dog`s diet can actually lead to the development of a lipoma. Carbohydrates, chemical preservatives, and other toxins found in processed food all contribute to fatty tumor growth.
It depends on how aggressive or advanced the particular cancer is. By the time it`s detected, some dogs will live weeks to months, while others will live for years. Lymphoma patients, for instance, can live several years.
Of submitted samples, 20% to 40% are reported to be malignant. The most common malignant skin tumors in dogs are mast cell tumors, soft tissue sarcomas, and squamous cell carcinomas. The most common benign canine skin and subcutaneous benign tumors include lipomas, histiocytomas, and perianal gland adenomas.
Skin Growths

They are often painful and can contain large amounts of blood and pus with the possibility of rupturing. Apocrine Cysts: These cysts are caused by obstructed skin glands. Think of them much like a human pimple. They may also rupture, which often helps clear them up.

Most lumps and swellings are benign (not cancerous) and are harmless, especially the kind that feel soft and roll easily under the fingers (such as lipomas and cysts). A lump or swelling that appears suddenly (over 24 to 48 hours) and is painful is usually caused by an injury or an infection.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Q. Small lump on my dog’s throat, what should I do?
ANSWER : A. Lumps and bumps on the throat or neck can be caused by a wide range of things. Depending on the lumps size, if it is under the skin or appears on the skin itself, and its location on the throat can all indicate different things.

There are a large number of structures in the neck there ranging from thyroid glands, nerves, salivary glands and even lymph nodes. Illness, disease or irritation can all cause swelling or issues there. You may also see additional symptoms such as trouble swallowing, drooling, lethargy or changes in weight and appetite to help narrow down the cause of the lump. Testing via blood work or an X-ray may help to determine the cause and proper treatment.

Lumps and bumps on the skin can also be caused by allergies such as an allergic reaction or sting, or even an abscess under the skin. Allergies are usually treated with an allergy medication to help stop the response and any itching or redness. Abscesses (cuts or scrapes that get infected and swell with fluid) are usually hot or painful to the touch and may ooze debris. These are usually drained at a vet, and then treated with antibiotics.

If the cause of the lump is not known, your vet may also recommend taking a sample of the lump to send to a Lab. This can help to determine what exactly is causing the lump and how to treat it.

Q. I have a Peagle who is 3 years old. He eats everything in sight. I have noticed about a week ago that he has a lump in his lower abdomen. He is overwe
ANSWER : A. It’s often difficult to tell whether lumps, if what you’re talking about is actually inside the abdomen, are normal or not. A vet is trained to “palpate” or feel the abdomen and discern the individual organs, and whether they feel abnormal or not. There are many structures in there, from kidneys to the liver to lymph node. It takes quite a bit of training to know what a “normal” abdomen feels like.

If you’re talking about a lump you’re feeling under the skin, this could be something benign or malignant. Hopefully it’s nothing serious, but it’s best to get it checked out. And you should be aware that a ravenous appetite can be the sign of some hormonal diseases, although I’ve also known a lot of Beagles (which is sounds like is half of what makes up your dog) who were ravenous eaters, so he may be prone to overeating. Your vet can also determine if he’s overweight and give you diet and exercise tips for him.

Q. My cat threw up last night and is now sensitive and making pain noises, stomach is large and is moving slowly. What’s wrong?
ANSWER : A. If your cat is vomiting and appears to have a painful abdomen. (Vocalized when touched on the abdomen, or hunches and arches his back when walking) it may indicate a problem with his digestive tract. Foreign bodies such as string or hair, digestive upset, or illness and even disease can all cause the abdomen to become painful.

Additional symptoms may include continued vomiting or diarrhea, or blood visible in either one. Since your cat’s abdomen is painful, it is best to make an appointment with your local vet to rule out any serious issues such as a foreign body or illness.

Q. My Boston has large lumps on her abdomen that appeared over night what could that be
ANSWER : A. It sounds like it is an allergic reaction. If they don’t start to go down in a few hours, get worse or the dog has any other symptoms then you should see your vet as soon as possible.

Q. My Cocker Spaniel keeps getting lumps on her body. She has some on the top of her head that feel soft with about six or so clumped together.
ANSWER : A. Lumps and bumps are very common in dogs. They can be caused by any number of things ranging from allergic reactions, to pockets of infection under the skin, to various tumors and cysts. If the bumps are spreading rapidly, or are very bothersome to your dog it is best to have a vet look at it to make sure it is not serious.

Allergic reaction bumps will often appear as small, red, itchy pockets of bumps anywhere on the body. These are usually treated with an allergy medication or over the counter antihistamine. Abscesses are pockets of infection under the skin that usually are one large bump, however in spreading infections may have other bumps appear. These are often painful or hot to the touch, and may ooze debris that is yellow or greenish in color. Abscesses are usually drained and then an antibiotic given to clear up the infection. Some tumors can also appear as small bumps that begin to spread and their type can be determined through biopsy of the site if other more common causes are ruled out.

Until you can have your vet look at the lumps, it is best to stop your dog from licking or chewing at them. Licking and chewing can cause cuts and scrapes to open, allowing bacteria and infection to spread over the affected area. An Elizabethan collar, or a T-shirt over the affected area can help prevent licking and chewing.

Q. My dog is bleeding out of rearend after
going to vet for a leg trouble the vet says
it is stres
ANSWER : A. It could be many things causing the problem. If it is an unneutered female it could be a season, if it is in the urine it could be a cystitis which could be set of by stress amongst other things. It could be from the anal glands or it could be from the lower intestinal tract. If it is the latter I would be careful what pain relief medication you are giving as some can cause bleeding in the GI tract such as meloxicam. I would recommend having a recheck with your vet to establish where the bleeding is coming from as some causes may require treatment or a change in current treatment.

Q. My dog has had dark red blood in stools for 2 days now . She found & ate a baby bird back in August , could that cause a problem now after so long
ANSWER : A. It seems pretty unlikely to me that the bird ingestion could have anything to do with the blood in the stool you’re seeing now. Depending on exactly how it looks, it could be a number of things. If the stool is normal and has blood on it, it could be an anal gland problem (infection, tumor) or a problem inside the rectum, like a mass. If she’s got diarrhea along with blood, she could have a bacterial or parasitic infection in her intestines, or she could have inflammatory bowel disease. I’d get this checked out as soon as possible.

Read Full Q/A … : Causes of Blood in Dog Stool

Q. We have a cocker spaniel that is about 12 years old. He has a lump about 3/4 of an inch under his lower eye lid. It is solid and very irritated.
ANSWER : A. So this lump is ON his eyelid? Or on the skin below the eyelid? Could be a couple of things. There’s a pretty common “benign” tumor of the eyelid called a Meibomiam gland adenoma. Not really cancer, doesn’t metastasize. But I put benign in quotes because they can be very irritating to the eye itself, obstructing vision and causing corneal ulcers. These can sometimes be frozen off with liquid nitrogen, but if it’s 3/4 of an inch it will definitely need surgery to remove.

If it’s below the eyelid it could be any number of skin tumors that dogs get – again, some benign, some not – or it could be a small abscess. Have your vet check it out. He could likely stick a needle in it and get some cells out to figure out what it is, then devise a treatment plan to deal with it.