I'm sorry to hear that your dog is unwell.
I suspect these bumps are due to one of two things: an allergic reaction, or small skin infections/pustules from something like insect bites.
It's likely that your dog is experiencing a case of hives or contact dermatitis as the result of an allergic reaction. The irritation and itching can result in breakages in the skin that results in small pockets of infection and pustules, which then drain, dry up and scab and then heal. This could be what's occurring here.
The reaction can occur suddenly and an allergy can develop to something they've been exposed to many times before. Foods, chemicals (like detergents, household cleaners), grooming products, pesticides, pollens and other environmental elements, medicines and vaccines, parasites and fleas, eating a plant - all of these things can cause allergies in your pet. There's two ways that allergies occur: one way is that the allergen is ingested, the other way is when the allergen comes in contact with the skin.
So with these possible causes in mind, I would think very hard about anything she's been exposed to within the past 24 hours. Anything at all. If we can identify a possible allergen, it will help with treating it and it will help prevent this from occurring again.
If your dog is, in fact, suffering from an allergic reaction, Benadryl will help reduce the swelling and any itching that your dog is experiencing. If the Benadryl does help, then you'll know that you're dealing with an allergy. (Although some allergies are so severe that the Benadryl does very little - sometimes, you need high doses of anti-histimine, often via injection. In terms of efficacy, Benadryl isn't all that potent in dogs) It may make her a bit sleepy and I would check with your vet first, especially if she's on other meds.
The dosage is 1mg per 1 pound of body weight up to 50 mgs. This can be given every eight hours. This should help and reduce the symptoms that your dog is experiencing. I would take her to the vet today. It's possible that this is a situation where the allergen is still present and she could be getting worse. In extreme cases, the swelling can affect the throat and windpipe, making breathing labored. Facial swelling and swelling of the paws is also common.
I would also start by washing the affected area with dish soap, followed by oatmeal bath. You only need to do this once. If she's come in contact with something like a plant or some chemicals, the oils are what cause the reaction. And the oils can be difficult to wash away. Dish soap breaks up oils. And I would follow this with oatmeal bath, which will be soothing. If she begins to get itchy, you can also try some hydrocortisone cream or a spray (the spray is available in the pet section of pet supply stores and even grocery and drug stores - I know Hartz makes a spray).
I think it's also possible that you're dealing with a case of acne or acne that's leading to bacterial infections. This often occurs when oils from food and bacteria trigger pore/follicle blockages and infections. Does your dog eat from a plastic food bowl? If so, I would strongly recommend switching to ceramic or metal, as small scratches in the plastic harbor bacteria and this worsens acne. The acne can then spread to the neck, chest, paws, legs, etc.
Cystic acne is a bit different from traditional acne. The most common types of lesions in this category are sebaceous cysts, which occur when dirt, oils and dead skin cells block the dog's pores, and sebum (the oil that moistens our skin) cannot escape, so it builds up under the skin, forming a cyst. These can also start out as blackheads and then grow into more traditional cysts over time. They can also get infected, particularly if you pick at them, making them red and inflammed. The lesions aren't necessarily red and inflammed. They are often the same color as the surrounding skin. They usually start out as a small bump under the skin and then grow larger over time. I've seen some that are a couple of inches across.
A normal sebaceous cyst will contain a thick, toothpaste-like paste. It's not a true infection when the cyst first starts out, but these cysts often do get infected and this is when they tend to get red and inflammed. Often, if you pick at the cyst or if it partially ruptures, you can end up with an infection and you'll also see normal pus and fluid. I should also mention that you don't always necessarily see the drainage process. It takes just a second for the lesion to drain and the drainage can easily be wiped away, allowing for scabs to form. I should also note that it's not uncommon to see the hair disappear with the scabs too.
It's also possible for a bug bite, particularly when you're dealing with ants, to cause skin infections that are similar in appearance to acne or cysts. You can end up with pustules that break open and dry up like you described.
You can also see a case where an allergic reaction makes the dog itchy, and when the itching occurs, the skin is broken, and you end up with small little pockets of infection. A bacterial infection can also spread in this way, so you can end up with an infection in one area and itching or other skin-to-skin contact can result in the problem spreading.
There are a few measures you can take at home to help the situation, whatever the cause. You'll need to keep the area clean and disinfected to avoid infection and to promote healing. Whenever the skin is broken, there's a chance of infection.
I would begin by using an antibacterial soap like Dial to wash the affected area once a day. Do this until healing is complete.
Twice a day you should disinfect with the betadine, and apply the antibiotic cream. I would do this once after the washing and once later in the day. So maybe morning and night.
If the lesions do appear to be due to acne or cysts, and are a little more stubborn, you can try a wash with benzoyl peroxide, which you can use two or three times a week. This should help heal the bumps, especially if they're a form of acne.
If see some improvement but the bumps aren't gone completely, it will be time to visit the vet. Some more stubborn cases of acne require a topical corticosteroid to help with the inflammation, combined with antibiotics, sometimes for several weeks. Both would have to be prescribed by your vet, but it is a non-surgical option that may be effective in your dog's case if acne, cysts or some other skin infection is to blame. Often, you end up with recurrent cysts involving the same damaged pores of the skin, so you may have to have the cysts excised. This will prevent them from returning.
It may also be worth having your vet take a culture of the lesions. This will tell him exactly what type of bacteria is present, if an infection is to blame. Once you can determine this, you can determine how to best treat the area.
Also, I would consider trying your dog on a duck and potato dog food. If a food allergy is to blame, this is often a helpful formula. Here's some links to some brands that make this formula:
Trying him on plain white rice and chicken or boiled hamburger for a week or so may also help, as it's likely you'll eliminate the allergen if the allergen is an ingredient of his food. If you see improvement, then you know an allergy is to blame.
Here's a few websites on cysts and other growths: http://www.petplace.com/dogs/acne-in-dogs/page1.aspx http://www.petplace.com/dogs/sebaceous-cysts-in-dogs/page1.aspx http://www.marvistavet.com/html/body_yeast_infection_of_the_skin.html http://www.vetinfo.com/dencyclopedia/deacne.html http://www.bestdogarticles.com/Article/Could-your-Dog-be-Suffering-from-Canine-Acne-/976
Here's some links on allergies and itching:
Here's a couple of articles that you may find helpful:
Also, in case you are dealing with an allergic reaction, you're going to want to watch out for signs of a serious problem. Symptoms that require an immediate trip to the vet include facial swelling, swelling of the paws and feet, and labored breathing.
I hope your dog is doing better soon! Don't hesitate to let me know if you require any additional information!
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