Pimples and Pustules
Dogs and cats can develop pimples and pustules much like teenagers.They are usually the result of an underlying allergy e.g. contact allergy, flea allergy. Left untreated, they quickly spread and in some cases turn into hot spots.
They are caused by bacteria, usually a streptococcus ("strep") or staphylococcus ("staph"). The staph is a cousin of the Golden Staph seen in human infections and can be tough to clear up with traditional antibiotics like penicillin. Streps and Staphs live in low numbers naturally on the skin surface.
Once the top protective layers of the skin are damaged, these bacteria find a way into the deeper skin layers e.g. when the itching pets scratch and/or bite itchy skin. Here, they find conditions nice and ripe for multiplying. The body mounts a defence against them "throwing" white blood cells WBC) and proteins into the battle. The WBC "gobble-up" the bacteria. Pus is formed by the combined WBC, bacteria and protein.
When the pimples or pustules burst, the bacteria spread out from the eruption zone like lava streaming down a volcano's sides. As they spread outwards, they find new skin to "attack". As they spread, the lesion changes to one of a circular ring with an outer edge of lifting skin that looks like dead skin from a bad case of sunburn. This is called an epidermal collarette.
These pimples, pustules and epidermal collarettes can be very itchy, and the pet does more damage licking or scratching them, and the cycle continues.
The lesions should be examined under the microscope using a Dif Quik Stain to rule out any other "invaders" e.g. Demodex mange mites, yeasts.
Once the vet is confident there are no other invaders, anti-biotics are given, sometimes for 3-4 weeks in chronic cases.
Use of Dermcare Shampoos help attack the bacteria form the surface e.g. Pyohex, Malaseb. .
The underlying cause of the allergy needs to be determined and appropriate treatment undertaken to lessen the underlying problem.
Pimples in a dog's skin secondary
Pustules in the groin due to
Erythema (inflammation) and epidermal