It's very possible that this is a case of acne. 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.
I think it's likely that you're dealing with cystic acne here. 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.
There are a few measures you can take at home to help the situation. I would begin by using an antibacterial soap to wash her muzzle and chin after meals.
You'll also want to drain the cysts that she does have, as they won't disappear on their own. Either you can drain them or you can wait for them to rupture which is a messy ordeal, especially when they're large. Once they rupture and drain, you end up with a big hole in the dog's skin that you have to heal - not fun! You can begin the process by applying a warm compress (like a warm washcloth) for about ten or fifteen minutes, as this will soften the skin and bring the infection to the surface and soften the contents of the cyst. You can then lance the area with a disinfected needle and drain as much of the contents as possible. Just prick the surface - don't stick the entire needle into her skin. Often, when the skin is sufficiently softened from the warm compresses, you don't need to do all that much.
When you're done draining, clean the area with betadine (found in the first aid section of the drug store) and swab some onto the area and allow it to air dry. You can then apply some antibiotic cream (not ointment, as this can clog pores and create more problems). This should help promote healing. If the area appears to be re-filling with pus or sebum, you can repeat the draining process, which may be necessary several times.
If the cysts 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 you still don't see any improvement, 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. An option would be to try her on some topical steroids (to help with inflammation) and oral antibiotics (to help with the infection). 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. 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.
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.vetinfo.com/dencyclopedia/deacne.html http://www.bestdogarticles.com/Article/Could-your-Dog-be-Suffering-from-Canine-Acne-/976
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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