The Violet Gland, and Stud Tail

Does your dog have a tail? If yes, then you might have noticed an area on the top of the tail about ⅓ of the way along from the base which has a different appearance? This is the ‘violet’ or supracaudal gland’, which is a patch of specialised sebaceous (oil-producing) skin. It is present in both male and female dogs, and in other canids including wolves and foxes.

In some domestic dogs it is barely visible, and in others (especially short haired breeds) it can be more prominent as the fur here can be quite sparse and the skin darker.  My Labrador Belle had quite a visible one.

See images below.

The violet glands functions include:

• Producing oily secretions that help condition the skin and coat.

• Contributing intra-species communication. The gland secretes a mixture of volatile terpenes similar to those produced by violets, hence the name.

A healthy violet gland is not itchy or scabby, and is a normal part of the dog’s anatomy and therefore nothing to worry about.

What is stud tail?

Stud tail is a condition in which the supracaudal (violet) gland becomes overactive and enlarged.

In this scenario there can be crusting of the skin, blackheads and secondary infections can take hold.  If this happens then excessive licking / chewing can occur.

Although it is called “stud tail,” it can occur in any dog, but it is most common in intact males, hence the name.

In stud tail, the gland’s sebaceous cells become excessively active, producing too much oil. Hormones, particularly androgens such as testosterone appear to play an important role, which is why the condition is more common in intact male dogs.

Why do some dogs get stud tail?

Risk factors include:

• Being an intact male.

• Individual predisposition.

• Hormonal influences.

• Occasionally underlying skin disorders that worsen the condition.

If there are signs of blackheads, hair loss, redness, an unpleasant odour or other signs of infection it’s best to consult your vet. Treatment typically involves medicated shampoos, degreasing products, management of any infection, and sometimes addressing hormonal factors.

So, in conclusion: every dog has a violet (supracaudal) gland, but only some dogs will ever develop stud tail.