Stud tail is the nickname for the skin condition that can cause a focal bald spot on the top of the tail. This bald spot is typically located a few centimeters away from the base of the tail and is located over the supracaudal tail gland. The supracaudal tail gland is also sometimes called the oval tail gland (or the violet gland in foxes).
This area of the tail contains a lot of sebaceous glands and some sweat glands. Sebaceous glands are oil glands concentrated in the skin. When the glandular structures in this area start to enlarge (called tail gland hyperplasia) this can cause excess accumulation of oily secretions and can lead to matted hair, hair loss, clogged hair follicles and secondary skin infections.
To treat clogged pores (comedones) on the tail, you can try using daily to every other day use of Stridex pads. Or, after cleaning, apply Adaptalene gel to the site once daily.
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The violet gland of wild canids
The tail gland originally developed in wild canids to produce a scent as a form of “chemical “ communication between wild canids. The tail glands of foxes are the most developed and produce a lot of chemical compounds that can smell intensely. The chemical smell is similar to the odor produced by a violet (hence the name violet gland). If you look at a Fox’s tail you will see a black spot of tail fur which is exactly where the violet gland is located. Fox will rub their tails against trees to mark and this helps them create a scent trail. Luckily, the same gland in dogs is not as developed as a Fox and does not produce any odors or scents.
Characteristics of the skin over the tail gland
Because of the high density of glandular structures under the skin in this area, the hair follicles are prone to developing an accumulation of excess oil. This can clog the hair follicles and cause localized hair loss and comedones on the skin. More severe cases can lead to infection of the skin in and around the hair follicles called folliculitis and furunculosis. Folliculitis is a very localized inflammation or infection of the hair follicle and is more superficial in the skin. Furunculosis refers to a deeper, more wide spread infection around the hair follicle. In furunculosis, the hair follicle rupture and you might be able to squeeze out pus. This can happen anywhere where there is fur growing on the skin.
The two best medicated shampoos for stud tail in dogs are:
Dechra’s DermaBenSx Shampoo for Dogs, Cats and Horses.
Pet MD Benzoyl Peroxide Medicated Shampoo for Dogs and Cats
These shampoos contain the right amounts of benzoyl peroxide and salicylic acid to flush the pores, treat infection, and remove grease and scale.
The supracaudal tail gland contains hepatoid glandular structures that can swell in response to the presence of testosterone. In unneutered male dogs, the presence of testosterone can sometimes lead to swelling of the tail glands. The glandular swelling can cause hair loss or even some bulging in this area. If a dog is later neutered, the signs of stud tail may resolve.
Other imbalances of hormones such as low thyroid hormone, an imbalance of sex hormones, or elevated steroid hormones (Cushings’ disease) from the adrenal glands can lead to arrest of the hair cycle. Testicular cancers can also cause hair loss over the tail due to overproduction of testosterone. Hormone imbalances can cause the longer thicker guard hairs to fall out, leaving behind the more downy smaller hairs.
Why the hair over a dog’s tail tends to fall out
Most hair follicles in the skin grow a thick, long guard hair (primary hair) and between 6-12 more downy hairs. The hair over the tail gland is unique because each hair follicle only has a single hair ( a guard hair)! This means conditions that affect the health of the follicle or influence the growth of the hair will be more likely to cause a bald patch on the tail in this area.
Dogs with secondary localized skin infections may rub more along their tail. This can perpetuate and lead to more hair loss. Dogs with more generalized hairloss conditions, such as Pomeranians with Alopecia X, will first lose the hair in the areas of highest friction: the tail, trunk, neck, perineum and backs of the thighs.
Unfortunately many dogs with supracaudal tail gland hyperplasia will have cyclic problems with localized hair loss on their tails. Luckily, the hair loss is usually just a cosmetic issue. If the skin is red, inflamed or bumpy with comedones it should be treated.
Swelling of the base of the tail in a dog
Sometimes, if there is swelling at the site of the tail gland, the area may be recommended to be biopsied. A biopsy can determine if the area is simply swollen from hyperplasia of the glands or enlarged due to a tumor. It is not possible to determine by examination alone whether the enlarged swelling of the tail base is due to a tumor or just hyperplasia of the sebaceous glands of the skin. A punch biopsy (under sedation/anesthesia) can take a small piece of tissue from the area that can be analyzed microscopically. Benign swelling is composed of excess numbers of glandular cells. A tumor would show infiltration of the area with tumor cells.
This is a picture of a dog with benign hyperplasia of the tail gland. This diagnosis was determined by a surgical biopsy of the site.
The dog was an unneutered male dog, so neutering was recommended.
In addition to swelling of the glandular tissue of the tail, some dogs may also have dry, thickened skin around the anus. This is because both these locations contain similar types of sebaceous glands that can grow under the influence of testosterone.
Although elevated androgen levels can cause stud tail in some dogs, it can develop in both males and females. A predisposition to seborrheic skin disease can also cause stud tail. This skin disease is a condition that causes oily flaky skin and there is no breed predilection . However, unneutered dmale dogs are more often affected.
Factors the predispose a pet to developing stud tail
The presence of excess oily secretions in the tail gland region can cause hair loss if there are other influencing factors such as:
- Allergic skin disease
- Secondary bacterial or yeast skin infection
- Demodex infection
- Sex hormone imbalance
- Hypothyroidism
- Cushing’s disease
Hypothyroidism is a common endocrine condition found in dogs. It can produce changes to the skin such as scaling and a tendency to have skin infections. Coat changes such as thinning fur on the tail or over the trunk is common. In addition, dogs with hypothyroidism often gain weight and act sluggish. It develops more commonly in middle aged dogs and is easily diagnosed by measuring thyroid hormone levels in the blood.
This is a picture of a dog diagnosed with hypothyroidism. The hairloss over the tail was caused by low thyroid hormone.
Characteristics of the skin
Most cases of stud tail are characterized by a bumpy, inflamed, hairless patch of skin over the tail. Comedones and darkening of the skin might be present. The darkening of the skin is due to excess pigment that gets deposited in the skin secondary to chronic inflammation or allergy.
The dog’s tail below shows darkening of the skin, clogged hair follicles (comedones) and bumpy skin with hair loss.
The second picture shows how much the skin has improved with 2 weeks of oral antibiotics. You can still see some signs of bumpy skin. Likely this patient needs more time on antibiotics to help clear up the infection and encourage the skin to regrow hair.
How to treat stud tail
More severe cases of stud tail may require oral antibiotics. However, there are a lot of good topical treatment options for stud tail. It is possible to treat stud tail at home by using the proper topical treatments.
Using a medicated shampoo with keratolytic and keratoplastic effects on the skin can really help. A medicated shampoo should be used 3 times a week and lathered onto the affected skin. The shampoo should not be rinsed off for at least 10 minutes of contact time.
Best shampoo to treat stud tail
Two really good topical shampoos for treating stud tail are easily available on Amazon. These two shampoos work well for stud tail because they contain a follicular flushing product called Benzoyl peroxide. Dechra’s shampoo contains 2.5% Benzoyl peroxide and PetMd’s shampoo contains 3% Benzoyl peroxide.
In addition to the Benzoyl peroxide, these shampoos also contain salicylic acid, between 1-2%.
Dechra’s DermaBenSx Shampoo for Dogs, Cats and Horses.
2.5% Benzoyl Peroxide, 1% Sodium Thiosulfate, 1% Salicylic Acid, Ceramide
Pet MD Benzoyl Peroxide Medicated Shampoo for Dogs and Cats
3% Benzoyl Peroxide, 2% Salicylic Acid, and 2% Sulfur
Benzoyl peroxide has antibacterial activity and helps by removing grease as well. Sulfur and salicylic acid are synergistic together. They are useful for dry, waxy, scaly skin. These products dissolve excess skin and smooth skin by normalizing the skin’s excess cell turnover.
Is coconut oil useful for stud tail treatment?
Using coconut oil alone will likely not be sufficient to treat a skin infection caused by stud tail. It is important to degrease the skin, flush the pores, and use an antibacterial agent to treat stud tail. Using a medicated shampoo like one of the two I recommend above can provide this treatment to the skin. However, adding an emollient to the skin like coconut oil can help increase the skin’s hydration.
Vegetable oils (like coconut oil) can help provide this emollient protection. Coconut oil is part of some cleaning and moisturizing shampoos useful for the more dry forms of seborrhea. For example, it’s present in DermaLyte shampoo: a hydrating and moisturizing veterinary shampoo that helps restore the skin’s natural skin barrier.
Coconut oil can be used after shampooing with a medicated shampoo containing benzoyl peroxide and salicylic acid. The oils improve skin texture and many help reduce skin inflammation and assist skin repair. Unfortunately, it cannot help grow hair.
Prognosis for stud tail
Stud tail is mostly a cosmetic condition.Although it looks unsightly, It rarely will cause any serious problems other than an area of local skin infection and inflammation. A secondary skin infection should be treated with topical therapy and/ or oral therapy as recommended by your veterinarian. The skin over the supracaudal skin gland is most susceptible to local hair loss because there are only solitary guard hairs in this area. If the skin becomes greasy and the hair follicles become clogged or infected, the hair over the tail gland is likely to fall out. This area of the tail is rich with skin glands that may enlarge in response to excess testosterone. Thus, the area may swell in some dogs. Other hormone imbalances such as low thyroid, or excess steroid hormone, can cause the hair to fall out by arresting the hair cycle.
How easily stud tail can be treated ultimately depends on the underlying cause. Many dogs with stud tail aggravated by underlying skin allergies or seborrheic skin disease have cyclic episodes of their stud tail.