Screw-tail, also known as corkscrew tail or ingrown tail, is a common condition in certain breeds: namely, brachycephalic breeds including the English Bulldog, French Bulldog and Boston Terrier. Pugs can also be affected. Screw-tail describes short tails with an abnormally tight curve, resulting in a corkscrew shape tail that is often set back where it meets the body. These tails are coiled when relaxed, and depending on the severity of the condition they may or may not be able to be straightened.
The resulting tail is at high risk of severe, recurrent skin infections due to its skin folds – but the underlying deformities that cause the screw tail are also a cause for concern.
Table of contents
What causes screw-tail?
The short answer is breeding – screw-tail is an inherited trait. When selecting dogs of certain breeds to breed from, we have prized a short, curly tail. These breeds are primarily the English and French Bulldog, Boston Terrier and Pug, though others can be affected. In selecting dogs with short or very curled tails, we have selected those with missing and deformed vertebrae (e.g. hemi-vertebrae and butterfly vertebrae).
These missing and deformed vertebrae can produce a ‘cute’ and characteristically short and curly tail – but there is a cost.
Skin infections associated with screw-tail
Dogs with screw-tail are predisposed to repeated, severe bouts of pyoderma (skin infections) throughout their lives, also known as intertrigo or skin fold dermatitis. These are caused by the moist, warm environment created by their excessive tail skin folds. In severe cases, their tail deformities may partially obstruct the anus and cause faeces to become trapped in these skin folds.
Symptoms include itching, scooting, chewing, malodour, discharge – and pain. This condition can have a significant impact on dogs’ quality of life. So, what can be done to manage it?
Medical management of pyoderma associated with screw-tail consists of lifelong cleaning and home care, with regular courses of antibiotics and pain relief or anti-itch medication during flare ups of infection. Affected dogs may require cleaning after every bowel movement – but even with this care, infections remain common. Unfortunately, although cleaning is essential, this can exacerbate the humid environment created by the skin folds and ultimately still fuel a vicious cycle of infection.
Alternatively, surgery is an option. While this comes with some risks – including wound breakdown and infection – this can give dogs a better quality of life long-term. Surgery consists of either partial or full amputation of the (already short) tail.
Spinal problems associated with screw-tail
Screw-tail is typically caused by deformed vertebrae – which we have sadly selected for in many affected breeds, either for a substantially shortened or exaggeratedly curly tail. The preferred appearance for some of these breeds is so extreme that affected dogs appear almost tailless.
Dogs’ tails are not standalone structures; rather, they are a continuation of the spine. The deformed vertebrae in these breeds are often not limited to the tail but affect the rest of the spine as well.
In French and British Bulldogs and Boston Terriers, a specific gene has been identified that causes both screw-tail and deformities affecting the rest of the spine1; the Australian Veterinary Association recommends genetic testing of all dogs in these breeds and states that affected dogs ‘must not be bred or shown’2.
In breeds predisposed to screw-tail, a high incidence of deformities along the rest of the spine has been identified; in 2017, a study determined that a shocking 93.5% of French Bulldogs had hemivertebrae in their spine3, while Pugs and English Bulldogs also had an increased frequency of malformed vertebrae.
These figures are not normal – and while affected dogs may live happy lives, a disproportionate number will go on to develop painful and unnecessary neurological complications. These include intervertebral disc disease (IVDD), for example4: a condition for which, sadly, severely affected dogs may require euthanasia.
So, is screw-tail a cosmetic concern, or even a desirable trait for these breeds? With the evidence we now have, it really shouldn’t be.
Don’t dogs need a tail?
One of the main treatments for screw-tail is amputation – but don’t dogs need a tail? Cosmetic tail docking is illegal in the UK, partly because dogs’ tails play a vital role in communication; a 2018 review stated that tail behaviour is so vital to communication that docking ‘markedly impedes’ communication between dogs and between dogs and humans5. The short, relatively immobile tails seen in these breeds are already unable to communicate effectively6, so amputation of the remaining part of the tail is less of a concern.
Arguably, breeding dogs with such a short tail – whether it’s a screw-tail or not – is a significant welfare concern. The inability to communicate experienced by dogs with screw-tail, or other short or docked tails, may contribute to these dogs experiencing negative interactions with other dogs and becoming anxious or aggressive.
Conclusion
From severe skin infections to spinal deformities and even behavioural issues, it’s clear that screw-tail can have a significant impact on dogs’ quality of life. This trait is inherited, so the priority for new owners should be to identify parents with healthy tails and consider choosing a puppy that’s likely to have a longer, mobile tail. If a curly tail is your priority, try to avoid a severe screw-tail and consider finding a breeder willing to use x-rays to screen their dogs for spinal issues prior to breeding.
For those whose dogs are already affected, it’s important to manage this condition effectively for your dog’s long-term health; for mild cases, a medical care plan can be sufficient, but for severe cases surgery could greatly improve your dog’s quality of life.
References and further reading
- 1 – Mansour, T. A., Lucot, K., Konopelski, S. E., Dickinson, P. J., Sturges, B. K., Vernau, K. L., Choi, S., Stern, J. A., Thomasy, S. M., Döring, S., Verstraete, F. J. M., Johnson, E. G., York, D., Rebhun, R. B., Ho, H. H., Brown, C. T., & Bannasch, D. L. (2018). Whole genome variant association across 100 dogs identifies a frame shift mutation in DISHEVELLED 2 which contributes to Robinow-like syndrome in Bulldogs and related screw tail dog breeds. PLoS genetics, 14(12), e1007850. https://doi.org/10.1371/journal.pgen.1007850
- 2 – A. V. A. Brachycephalic Dog Breeding. Australian Veterinary Association. https://www.ava.com.au/policy-advocacy/policies/companion-animals-commercial-activities/brachycephalic-dog-breeding/
- 3 – Ryan, R., Gutierrez-Quintana, R., Ter Haar, G., & De Decker, S. (2017). Prevalence of thoracic vertebral malformations in French bulldogs, Pugs and English bulldogs with and without associated neurological deficits. Veterinary journal (London, England : 1997), 221, 25–29. https://doi.org/10.1016/j.tvjl.2017.01.018
- 4 – Inglez de Souza, M. C., Ryan, R., ter Haar, G., Packer, R. M., Volk, H. A., & De Decker, S. (2018). Evaluation of the influence of kyphosis and scoliosis on intervertebral disc extrusion in French bulldogs. BMC Veterinary Research, 14(1). https://doi.org/10.1186/s12917-017-1316-9
- 5 – Mellor D. J. (2018). Tail Docking of Canine Puppies: Reassessment of the Tail’s Role in Communication, the Acute Pain Caused by Docking and Interpretation of Behavioural Responses. Animals : an open access journal from MDPI, 8(6), 82. https://doi.org/10.3390/ani8060082
- 6 – Leaver & Reimchen. (2008). Behavioural responses of Canis familiaris to different tail lengths of a remotely-controlled life-size dog replica, Behaviour, 145(3), 377-390. doi: https://doi.org/10.1163/156853908783402894
- RSPCA KNOWLEDGEBASE. RSPCA Knowledgebase. (2022, February 25). https://kb.rspca.org.au/knowledge-base/what-are-the-welfare-issues-associated-with-spinal-abnormalities-and-screw-tails-in-brachycephalic-flat-faced-dogs
- Tail Fold Intertrigo (screw tail). Massachusetts Society for the Prevention of Cruelty to Animals – Angell. (2019, March 6). https://www.mspca.org/angell_services/tail-fold-intertrigo-screw-tail/
- Pug – Hemivertebrae. UFAW. https://www.ufaw.org.uk/dogs/pug-hemivertebrae
Discussion