Definition of Acne
Acne, also called chin pyoderma, puppy dermatitis, muzzle folliculitis, furunculosis or simply “pimples,” is a fairly common inflammatory condition that affects the lips, chins and muzzles of puppies and young adult dogs.
Occasionally, acne shows up in the genital region, the area beneath the tail or on the flank. What causes acne in dogs is not well-understood. However, canine acne is similar to acne in teen-aged people. It usually starts as hard, purplish-red raised areas and blackheads at the site of hair follicles.
Bacteria get into the plugged follicles and multiply, creating whiteheads, which are pimples filled with pus. While mild acne outbreaks usually don’t cause dogs much discomfort, severe acne can be extremely painful. It is important for owners to recognize the signs of acne, so that they can take appropriate steps to treat the condition and relieve their dog’s discomfort.
Causes and Prevention of Acne in Dogs
Causes of Canine Acne
The underlying cause of acne in dogs is not well-understood. Most authorities think that acne is the result of a bacterial infection which is secondary to a trauma or other trigger.
Some people suggest that local trauma to the muzzle and face contributes to canine acne, while others theorize that there is a genetic predisposition that contributes to the disorder. Still other experts think that hormones may play a triggering role, because acne is most common in young, growing dogs.
Whatever its precise cause, acne involves a build-up of sloughed epithelial cells from the outer, nonvascular layer of skin called keratin, and an oily substance called sebum which is secreted from the sebaceous glands through ducts that open into the hair follicles.
This combination of greasy sebum and skin debris causes hair follicles to become plugged, impacted, inflamed, raised and red. As the sebaceous glands continue to produce and secrete sebum, the inflammatory process worsens.
Eventually, acne lesions can rupture, making them prone to developing a secondary bacterial infection that makes the pimple ooze pus and come to a head, commonly referred to as a whitehead. Pus is a thick, white or yellow substance that is the by-product of bacterial digestion of body tissues.
Prevention of Acne
Keeping a young dog’s muzzle and chin clean and dry goes a long way towards preventing the onset of adolescent acne. Good grooming and hygiene in the face area is especially important for dogs that have deep facial skin folds, such as Boxers, Bulldogs, Pugs and Mastiffs.
However, like acne in human teenagers, acne in companion dogs is common irrespective of how often the animal is washed and thoroughly dried. While it can be difficult to fully prevent, canine acne usually manageable. Fortunately, it almost always eventually resolves on its own as the dog matures.
Owners of dogs with acne should follow the same advice given to humans with pimples, and that is do not pop them. Opening up an acne lesion before it drains on its own can cause the affected hair follicles to rupture beneath the outer layer of the skin, which in turn can lead to massive local inflammation and spread of secondary bacterial infection.
Diagnosing Acne in Dogs
Canine acne is usually more of a cosmetic distraction for owners of companion dogs than it is a serious medical condition. Most of the time, owners will notice a scattering of raised red bumps, or pimples, on the chin, lips or muzzle of their young dogs. Fortunately, acne is not difficult to diagnose, and there are a number of medical therapies that are quite effective in controlling the condition.
A diagnosis of canine acne usually is made based on the dog’s age, history and clinical presentation, and of course by ruling out other possible causes of the skin lesions. A veterinarian presented with a young dog showing pimple-like lesions, especially on its lips, chin or muzzle, usually will take samples of the affected areas by gently rubbing several of them with a sterile cotton swab.
She will then roll the samples from the swabs onto clean glass slides and look at them under a microscope in a process called cytology. The veterinarian will be looking for the presence of inflammatory cells, and especially for infectious bacterial cells. Unfortunately, in the early stages of acne, bacteria usually are difficult to isolate from the acne lesions.
As the condition progresses, the papules enlarge, become pustules and ultimately rupture, oozing pus. This condition is called suppurative folliculitis and furunculosis.
If severe acne doesn’t respond well to a course of broad spectrum antibiotics, samples of the pus can be sent to a laboratory for bacterial culture and sensitivity, which is a process designed to actually grow the offending organisms in a laboratory and then determine which particular antibiotic or antibiotics will eliminate them most effectively. Bacterial culture and sensitivity may be recommended, especially if the dog does not respond well to empiric antibiotic therapy.
Skin scrapings of deeper skin layers can also be taken and examined microscopically at the veterinary clinic for overgrowth of the canine mange mite known as Demodex canis. While this tiny parasite is normal in the hair follicles in small numbers, it can begin to reproduce uncontrollable, especially during adolescence when young dogs are producing more skin oils.
Skin biopsies can be taken and submitted to a laboratory for assessment of possible fungal or other infections, although this is not routinely done in simple cases of canine acne, because bacterial microorganisms are the usual culprits.
Most owners are readily able to identify acne when it affects their dogs’ chin, muzzle and/or lips. It certainly is worth a quick visit to the veterinarian to set up a sound treatment and cleansing protocol, in order to relieve any discomfort that the condition could be causing.
Symptoms and Signs of Acne in Dogs
Effects of Acne – From The Dog’s Point Of View
Mild outbreaks of acne usually do not cause a dog discomfort. More severe cases, especially those in which the lesions have become infected, impacted, hard and raised, draining or weeping, can be quite painful, however. Scratching at the inflamed area can open the pimples prematurely, promoting the spread of secondary bacterial infection.
Symptoms of Acne – What The Owner Sees
Most people know what acne lesions, known as pimples, look like. Owners of young growing dogs – especially large, short-haired breeds –should keep an eye on the area around their dog’s muzzle, lips and chin. They may notice one or more of the following signs of acne:
- Mild scabbing
- Blackheads, also called comedomes
- Redness and swelling from inflammation of hair follicles, known as folliculitis
- Small, discreet, solid, elevated skin lesions or bumps called papules
- Small, elevated, well-circumscribed, pus-filled lesions of the skin called pustules, which usually are thin-walled and rupture easily
- Furunculosis, which are deep, inflamed, infected, hard, pus-filled lesions of the skin and subcutaneous tissues with a central slough or core; sometimes referred to as boils; almost always caused by secondary bacterial infection
- Blisters, also called bullae or vesicles
- Expression of pain when the inflamed area of skin is touched
- Scarring, thickening and hardening of resolved superficial skin lesions
- Chronic acne lesions may resolve and recur
Dogs at Increased Risk
Canine acne is particularly common in young, large, short-coated purebred dogs, although it certainly can occur in any breed. While there is no well-recognized gender predisposition to developing acne, some authorities think that it might be more prevalent in neutered males.
Breeds that commonly develop puppy acne include the Boxer, Doberman Pinscher, Great Dane, Mastiff, English Bulldog, Weimaraner, German Short-Haired Pointer, Pit Bull Terrier, American Staffordshire Terrier, Pug and Rottweiler. Acne is also somewhat common in Golden Retrievers.
Treatment and Prognosis for Acne in Dogs
Goals of Treating Canine Acne
The goals of treating acne in dogs are to resolve the dog’s discomfort if any, eliminate any contributing primary or secondary bacterial, fungal or other infections and to control recurrent break-outs. It usually is not possible to determine the precise underlying cause of canine acne, especially in the early stages of the condition.
The choice of treatment for acne depends on how severe and chronic the condition is in any given animal. It is important to minimize trauma to the muzzle, chin or lips, including that which may result from rough treatment, scratching, hunting, playing with other dogs or toys or otherwise.
For example, if the dog is rubbing his chin on the carpet or chewing on toys or bones that cause excess salivation, the owner should take steps to prevent those behaviors. Excess moisture can set up a great environment for bacterial multiplication. Clipping the area can improve the effectiveness of topical acne treatments, as long as it is done carefully and doesn’t cause further trauma or rupture of the sores.
Mild cases of acne can benefit from gentle cleansing with a benzoyl peroxide shampoo or gel once a day until the acne is resolved, and then once a week thereafter or as necessary and recommended by the dog’s doctor.
However, benzoyl peroxide can be mildly irritating, especially if the acne wounds are open to the environment. It can also bleach or stain furniture, fabrics and carpeting, so be careful when applying it.
The veterinarian can recommend or prescribe certain creams, lotions or ointments that can be applied to the affected skin area topically, in addition to or instead of benzoyl peroxide washes.
Some of these topical treatments can be drying, greasy or irritating to the skin. Glucocorticoid anti-inflammatory medications can also be applied to areas affected by acne topically.
Most veterinarians recommend using these to reduce inflammation after secondary bacterial infections have been resolved, because steroids tend to suppress the immune system. Long-term use of steroids can have adverse side effects, such as adrenal gland suppression and local skin atrophy.
Systemic treatment with oral antibiotics for one to two months may be appropriate if particularly stubborn antibiotic-resistant bacteria are causing the infection. Sometimes, the veterinarian will start a dog with mild to moderate cases of acne on a broad-spectrum oral antibiotic to see if the condition resolves. This is called “empiric antibiotic treatment.”
If empiric treatment is not effective, a swab or biopsy sample of several affected areas can be taken and sent to a laboratory, where skilled pathologists will perform a culture and sensitivity to identify the exact bacterial organism involved in the infection and determine the most effective antibiotic to treat the condition.
Most dogs with acne have a good to excellent prognosis for full recovery. Many times, acne in dogs will resolve spontaneously when they reaches maturity. Some animals may require life-long treatment with topical lotions, creams, ointments or gels, but this is non-invasive and quite easy for most owners to administer. Owners should discuss the potential side effects of all treatment protocols with their dog’s veterinarian.