There are a few different types of skin conditions that cause discharge in dogs.
The most common one is seen as an area of moist sticky, often clear discharge over a very raw red area of skin. It can harden into a firm encrusted scab (or multiple scabs). These are known colloquially as a “hot spot” and cover a variety of underlying conditions.
They are often triggered by an underlying allergy, commonly seen with flea bite allergies or environmental or food allergies. Ruptured sebaceous cysts will cause discharge from the skin as well.
Hot Spots (acute moist dermatitis)
Clear, sticky, wound-like spots on your dog’s skin would describe something colloquially called a “hot spot”, or acute moist dermatitis. Hot Spots develop from a bacterial or fungal skin infection that occurs from damage to the skin. The discharge is often clear and sticky. The skin damage is caused by your dog themselves: licking, chewing, scratching or gnawing.
Usually the extra itchiness is caused by an underlying allergy such as a flea bite allergy, food or environmental allergy. The excessive itching and chewing causes further disruption of the skin’s normal bacterial presence. What starts as a small irritation or infection becomes an oozing, sticky, incredibly itchy patch of exposed skin that dogs just can’t leave alone.
Discharge that is yellow or sticky and pink and comes from a pocket within the skin most commonly indicates an abscess. Abscesses are a collection of pus that can occur anywhere on your dog’s body. They often occur because of a scratch, bite, or wound caused by another animal or some unknown oopsie.
You might notice a lump and it may be painful to the touch. It’s also common for dogs to run a fever and feel lethargic or inappetent when their body is fighting a bacterial infection such as this.
Discharge that is brown or white and chunky may describe a sebaceous cyst. Sebaceous cysts often look and feel like pimples and can be very tempting to squeeze.
Sebaceous cysts form when follicles in the skin that hold sebum become infected or impacted. Finding a lump on your dog is never fun (although popping pimples is), and these particular cysts can rupture if left untreated, creating a bigger problem.
Fungal or Yeast Infections
Fungal infections such as yeast infections often present as scaly, red, and incredibly itchy. Yeast infections typically habituate in their ears and paws, but can occur anywhere there is skin.
If you have a French Bulldog, Shar Pei or a dog with wrinkly skin, watch out between those skin folds; yeast like to hang out in there. Yeast infections often present with a specific, incomparable odor.