Alopecia and fur loss in degus

Localised hair loss, particularly on the limbs, is commonly reported in degus. Alopecia means a partial or complete loss of hair and has several possible causes. Excessive licking or chewing may remove large areas of fur, but the appearance alone does not establish the cause.

A veterinarian familiar with degus should diagnose and treat persistent hair loss. Assuming that it is simply stress-related may delay treatment of an underlying disease.

Behavioural problem or physical disease?

Hair loss may arise from skin disease, systemic illness, medication or self-directed behaviour. Dermatological and behavioural problems can coexist, so the assessment should consider both.¹ Stress-related chewing, often affecting the feet or legs, is described in degu clinical references.² In a retrospective study of 300 pet degus presented to one clinic, 13.33% had alopecia attributed to fur chewing. This does not support the earlier claim that one-third of all captive degus are affected.³ Dental disease and other painful conditions should also be considered.

Possible causes

• Systemic or hormonal disease: these causes are less well documented in degus than behavioural hair removal, but cannot be excluded solely because the species is small or the bald patch appears localised.
• Nutritional problems: an unsuitable diet may contribute to poor skin and coat condition. Adequate fibre and an appropriate overall mineral balance are important.²
• Moulting: heavy shedding may make the coat appear uneven. Persistent bare patches or damaged skin need further assessment.
• Medication: some medicines, including certain chemotherapy drugs in other species, can cause hair loss. This does not establish a routine chemotherapy protocol for degus.
• Fungal infection: dermatophytes can cause ringworm, which may also infect people.
• External parasites: mites and other ectoparasites can damage the coat and skin.⁴
• Trauma: burns, wounds and repeated friction can cause local hair loss.⁴
• Hygiene-related skin disease: persistently dirty or damp conditions may contribute to bacterial skin infection.
• Pain: an animal may lick or chew a painful area repeatedly.
• Stress: illness, surgery, excessive noise, inappropriate housing or nearby predators may contribute.
• Repetitive self-directed behaviour: persistent licking, chewing, pulling, scratching or sucking may remove fur or damage skin. Similar behaviour directed at a companion can cause bald patches on that animal. Such behaviour should not automatically be labelled a stereotypy or attributed to permanent anxiety without assessment.
• Dental problems: oral pain may be associated with fur chewing. Dental disease affected 60% of the 300 clinic patients in the cited study, rather than 76% of all degus.³

Signs to look for

Self-directed hair removal often affects the forelimbs or hindlimbs. When another degu removes the fur, affected areas may include the back, flanks, lower back or head. The skin may remain intact or show redness, bite marks, wounds and raw areas.

Behaviour-associated alopecia

Behaviour-associated hair loss is a recognised clinical problem, although its frequency in the wider pet population is not established.³ Social isolation, insufficient enrichment, conflict within a group and pain may all contribute.² A medical examination and an assessment of housing and social relationships are therefore complementary.

Management

Provide suitable space, compatible social companions and opportunities to perform normal behaviour. Wild groups described in the cited study included approximately four to six females and one to two males, but this is an ecological observation, not a prescription to create mixed-sex breeding groups in captivity.⁵ The needs and compatibility of the particular animals must guide housing decisions.

Tunnels, shelters, suitable wheels and foraging activities can provide occupation. Behavioural dermatology literature in other species also discusses the importance of environmental management, but those findings must not be treated as degu-specific treatment trials.⁶ Reduce excessive noise and inappropriate light exposure, provide a normal day–night cycle and protect the enclosure from threatening contact with dogs, cats or other predators.⁷

Photographs of behaviour-associated alopecia: Degoe-opvang Jodipro.

Fungal infection: dermatophytosis

Dermatophytosis has been reported in degus with hair loss.³ It is a fungal infection with potential zoonotic transmission. The Trichophyton mentagrophytes complex is among the dermatophytes reported in rodents. These infections generally do not fluoresce under a Wood’s lamp, so a negative lamp examination does not rule them out.

Diagnosis and treatment

The veterinarian may use fungal culture or other appropriate tests when dermatophytosis is suspected, then prescribe suitable antifungal treatment and advise on environmental cleaning and protection of people and other animals.

Other reported causes

Clinical reports also describe bacterial dermatitis, which may be associated with poor hygiene, and uncommon ectoparasitic dermatitis involving Demodex or the tropical rat mite, Ornithonyssus bacoti. The latter may bite people and cause skin lesions. Localised hair loss has also occurred over tumours, including reported myxosarcoma and histiocytoma.³ These possibilities reinforce the need to identify the cause before deciding on treatment.

Sources

Schwobthaler, F. (n.d.). Dermatologie et troubles comportementaux : une démarche globale. Comportement Animal, 40, 6–7. https://www.zoopsy.com/fiches_conseils/comportement-animal40-dermatologie-et-troubles-comportementaux-une-demarche-globale-schwobthaler.pdf

Kubiak, M. (2020). Handbook of Exotic Pet Medicine. https://doi.org/10.1002/9781119389934

Jekl, V., Hauptman, K., Knotek, Z. (2011). Diseases in pet degus: a retrospective study in 300 animals. J Small Anim Pract, 52(2), 107-112. https://doi.org/10.1111/j.1748-5827.2010.01028.x

Richardson, V. C. G. (2003). Diseases of Small Domestic Rodents. https://doi.org/10.1002/9780470690840

Ebensperger, L. A., et al. (2009). Instability Rules Social Groups in the Communal Breeder RodentOctodon degus. Ethology, 115(6), 540-554. https://doi.org/10.1111/j.1439-0310.2009.01635.x

Franchi ép. Giraud, L. (2001). Les psychodermatoses chez le chien. Thèse vétérinaire, 01-TOU3-4021, École nationale vétérinaire de Toulouse / Université Paul-Sabatier. https://archivet.envt.fr/oatao.univ-toulouse.fr/138/1/picco_138.PDF

Keeble, E., & Meredith, A. (Eds.) (2009). BSAVA manual of rodents and ferrets. British Small Animal Veterinary Association. Bibliographic reference retained; the previously cited DOI does not resolve.