Seasonal Flank Hair Loss in Dogs (Canine Recurrent Flank Alopecia, CRFA)
- Synonyms: Seasonal flank alopecia, cyclic flank alopecia, follicular dysplasia
- Occurrence: rarer
- Location of disease: Abdomen/pelvis, Skin/Fur
When to visit the vet?
Home care monitor at home and contact your vet if worse
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
Cyclical Recurrent Flank Alopecia (CRFA) is a dermatological condition in dogs characterized by seasonal or periodic hair loss, mostly on the flanks. This condition often occurs in autumn or winter and is caused by a disturbance in the hair growth cycle.
The most important facts at a glance
Canine Recurrent Flank Alopecia (CRFA) is a condition that causes seasonal hair loss on the flanks in dogs. The hair cycle is disrupted by a prolonged resting phase, leading to hair loss. The exact cause is still unknown, but it is suspected that hormonal fluctuations, particularly of melatonin levels, play a role. Melatonin, which is influenced by daylight, can become imbalanced in fall and winter, triggering the disease. Genetic factors also contribute to susceptibility, with certain breeds such as Boxers and Bulldogs being more frequently affected. Symptoms include seasonal hair loss, thin coat, and occasionally itchy, flaky skin. Diagnosis is based on clinical observation and the exclusion of other causes. Treatment is often not necessary, as the condition is usually cosmetic and the hair regrows in spring or summer. If desired, melatonin can be administered under veterinary supervision to normalize the hair growth cycle. Increasing the amount of light the dog receives in winter may also be helpful. The prognosis is good, as the condition does not cause health problems. Preventive measures include increasing daylight exposure in winter and possibly prophylactic administration of melatonin. Research focuses on genetic and environmental factors as well as the development of new treatment options.
Causes
Hair growth in dogs occurs in cycles consisting of a growth phase (anagen), a transition phase (catagen), and a resting phase (telogen). In CRFA, there is a disturbance of this cycle, especially a prolonged telogen phase, which leads to hair loss.
The exact mechanism leading to CRFA is not yet fully understood. It is believed that the condition is related to disrupted melatonin levels, a hormone that regulates the sleep-wake rhythm and seasonal changes in the body. Melatonin is produced through the influence of daylight on the pineal gland, and a reduction in daylight during fall and winter can lead to an imbalance.
Genetic factors also play a role, as certain breeds such as Boxers, Bulldogs, and Airedale Terriers are more frequently affected. This suggests that a genetic predisposition plays a role in susceptibility to CRFA.
Symptoms
The main symptom of CRFA is symmetrical alopecia on the dog’s flanks, that is, on both sides of the body. This hair loss can also include other areas such as the back or sides, but often remains limited to the flanks.
Apart from hair loss, the skin in affected regions often shows dark pigmentation (hyperpigmentation). The skin may appear smooth and shiny, but generally shows no signs of inflammation or itching.
The affected dogs usually do not show systemic symptoms such as fever or loss of appetite. The condition is mainly cosmetic and does not affect the general well-being of the dog.
Therapy
Since CRFA is usually a cosmetic condition, treatment can often be avoided unless the dog’s owner wants to improve its appearance. One possible treatment is the administration of melatonin, which can help normalize the hair growth cycle. However, melatonin should only be used under veterinary supervision, as the dosage is important.
In some dogs, improving living conditions, such as increasing the amount of daily light or providing UV light sources in the winter months, can be helpful. This can help regulate the natural melatonin level.
There is no specific medication that can cure CRFA, as the condition is usually self-limiting and the hair typically regrows on its own in spring or summer.
Prognosis and follow-up care
The prognosis for dogs with CRFA is excellent, as the condition is typically only cosmetic and does not cause health problems. The hair loss is temporary, and the hair usually grows back once seasonal conditions change.
However, some dogs may experience recurring episodes of CRFA year after year. In these dogs, long-term monitoring and occasional treatment may be necessary to improve their appearance.
Prevention
Prevention of CRFA is difficult, as the exact cause is not fully understood. However, certain measures can help reduce the risk or alleviate symptoms.
One way is to increase the amount of daylight the dog receives, especially in the winter months. This can be achieved by taking longer walks outdoors during the day or using special UV lamps indoors.
For dogs that are repeatedly affected, a prophylactic administration of melatonin can be considered to support hair growth. However, this should always be done in consultation with a veterinarian to ensure the correct dosage and safety.
Outlook on current research
Cyclic recurrent flank hair loss, also known as Canine Recurrent Flank Alopecia (CRFA), is a common yet poorly understood condition in dogs. Current research focuses on identifying the exact causes of this disease. Scientists suspect that hormonal fluctuations related to daylight length may play a role. This is supported by the observation that the condition often occurs during fall and winter months, when days become shorter.
A significant research approach involves understanding the genetic predispositions that lead to this condition more frequently in certain breeds. Breeds such as Boxers, Bulldogs, and Airedale Terriers appear to be more susceptible. Genetic studies aim to identify specific hereditary traits that increase the risk for CRFA. Additionally, researchers are investigating whether environmental factors, such as diet and lifestyle, influence the occurrence of the disease.
Another important research area is the development of treatment options. Currently, there is no specific cure for CRFA, and treatment mostly focuses on alleviating symptoms. Researchers are working to develop new medications and therapies that can stimulate hair growth and reduce hair loss. These include hormonal treatments and supplements that improve skin health.
Recently, research has also expanded to the role of the microbiome in relation to skin health and hair loss in dogs. Scientists are investigating how a balanced gut microbiota can strengthen the immune system and potentially help reduce the risk of CRFA. Studies examining the interaction between gut bacteria and skin conditions in dogs could open new approaches to prevention and treatment of CRFA.
In summary, research on CRFA is still in its early stages but is steadily progressing. With increasing understanding of the genetic, hormonal, and environmental factors contributing to the development of this condition, scientists hope to develop more effective diagnostic and therapy methods in the near future.
Frequently Asked Questions (FAQs)
1. What is cyclic recurrent hair loss on the flanks in dogs?
2. Which dogs are most commonly affected?
3. What are the main causes of CRFA?
4. How is CRFA diagnosed?
5. Is there a cure for CRFA?
6. Can CRFA be prevented?
7. Are there home remedies that can help?
8. What role does nutrition play in CRFA?
9. How can I help my dog with CRFA?
10. When should I take my dog to the vet?
Literature
- Verschuuren, M. U. M. Y., Schlotter, Y. M., & Leegwater, P. A. J. (2024). Investigation of the association of the MLPH gene with seasonal canine flank alopecia in Rhodesian Ridgeback dogs. Canine Medicine and Genetics, 11, Article 5. https://doi.org/10.1186/s40575-024-00139-2
- Verschuuren, M. U. M. Y., Schlotter, Y. M., & Leegwater, P. A. J. (2022). The efficacy of subcutaneous slow-release melatonin implants in the prevention of canine flank alopecia recurrence is uncertain: A double-blind, randomized, placebo-controlled study. Veterinary Dermatology, 33(6), 527–532. https://doi.org/10.1111/vde.13113
- Welle, M. M., Mecklenburg, L., Linek, M., & Peters-Kennedy, J. (2023). Canine noninflammatory alopecia: An approach to its classification and a diagnostic aid. Veterinary Pathology, 60(6), 748–769. https://doi.org/10.1177/03009858231170295
- Müntener, T., Schuepbach-Regula, G., Frank, L., Rüfenacht, S., & Welle, M. M. (2012). Canine noninflammatory alopecia: A comprehensive evaluation of common and distinguishing histological characteristics. Veterinary Dermatology, 23(3), 206–e44. https://doi.org/10.1111/j.1365-3164.2012.01049.x
- Daminet, S., & Paradis, M. (2000). Evaluation of thyroid function in dogs suffering from recurrent flank alopecia. The Canadian Veterinary Journal, 41(9), 699–703.
- Vandenabeele, S. I., De Cock, H., Van Ham, L., Meyer, E., & Daminet, S. (2013). Study of the behaviour of lesional and nonlesional skin of canine recurrent flank alopecia transplanted to athymic nude mice. Veterinary Dermatology, 24(5), 507–e122. https://doi.org/10.1111/vde.12059
- Scott, D. W. (1990). Seasonal flank alopecia in ovariohysterectomized dogs. The Cornell Veterinarian, 80(2), 187–195.