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Last Updated 15 May 2017
PurposeThis document is a guideline for investigators on the treatment of ulcerative dermatitis.
- Veterinary Personnel & Investigative Personnel
- Dermatitis: Inflammation of the skin.
- Ectoparasite: A parasite that inhabits the exterior of an organism.
What is ulcerative dermatitis?
- Ulcerative dermatitis (UD) is a common and well-recognized disease in C57BL/6 (B6) mice and related strains. Ulcerative dermatitis can lead to alopecia, ulceration, crusting and exudation of the affected areas. Severe pruritus may result in self-mutilation and deformity.
What is the cause of ulcerative dermatitis?
- The cause is unknown but is likely multi-factorial with an epigenetic component. Many studies have been performed (and are ongoing) as to the etiology and optimal treatment of this condition, but neither has been definitively identified.
- Risk factors for development of ulcerative dermatitis include a high fat diet as well as certain genotypes such as E or P selectin and inducible nitric oxide synthase knockouts.
- Ulcerative dermatitis may be spontaneous or may occur secondary to a break in the skin. Animals with fight wounds or who have been barbered should be monitored closely for progression to ulcerative dermatitis, especially if on a B6 background.
What does ulcerative dermatitis look like?
- Classically, lesions are pruritic and are located on the dorsum, in the cervical area, between the scapulae, in the axillary area or combinations of these. Small shallow lesions may rapidly progress to excoriation, ulceration and skin degloving.
What are complications of ulcerative dermatitis?
- As open wounds, dermatitis lesions offer an opportunity for secondary infection and other systemic effects including hypoalbuminemia (low blood albumin), reactive lymphadenopathy (lymph node enlargement), leukocytosis (increase in white blood cells), and others.
- If the lesions are allowed to progress, contractures of the skin may form. Depending on lesion location, these contractures may interfere with the animal's normal functions including ambulation, grooming, eating and/or drinking.
- Animals with severe dermatitis tend to be poor breeders. Retaining affected animals only for breeding purposes may not be the optimal course of action.
What happens when your mouse is diagnosed with ulcerative dermatitis?
- ULAM veterinary technicians will routinely perform a fur pluck to check for ectoparasites.
- Trimming the toenails of the mouse is currently the most efficacious treatment for this condition, although it is not 100% curative. The ULAM veterinary technicians will trim the nails on any mouse diagnosed with UD.
- In some cases, a topical treatment may be applied. A veterinary staff member will contact the investigator to work with them in determining which treatments are acceptable to use with his or her animal. Common topical treatments include silver sulfadiazine ointment and triple antibiotic ointment. Following consultation with a veterinarian, an opthalmic ointment may be prescribed for lesions around the eye. Also, the use of maropitant citrate (Cerenia®), a NK1 receptor antagonist, has shown potential to improve healing of UD lesions. A veterinary staff member will contact the investigator to work with them in determining which treatments are acceptable to use with his or her animal.
- The following guidelines are used by veterinary staff to determine humane endpoints in mice with ulcerative dermatitis. The investigator or lab manager will be contacted if euthanasia is warranted. In all cases, animals will be assessed in accordance with the End-Stage Illness Scoring System.
- Presence of lesions on the face or head which impair normal functions (eating and drinking).
- Presence of wounds, scar tissue or contractures that severely impede the animal's locomotion.
- Depression, lethargy, loss of body condition and/or anorexia indicating the wounds have resulted in generalized infection.
- Significant progression of a lesion (for example, greater than or equal to 1/4 the body surface area) after two weeks despite treatment.
- Severe ulceration with self-mutilation or bodily deformity.
- Case presentations may vary. Veterinary staff are available for consultation on treatment or determination of an appropriate endpoint in all cases.
- Differentials to consider for cases presenting with clinical signs of ulcerative dermatitis are ectoparasites, fight wounds, excessive barbaring, and bacterial skin infections.
- Adams SC, Garner JP, Felt SA, Geronimo JT, Chu DK. 2016. A “Pedi” Cures All: Toenail Trimming and the Treatment of Ulcerative Dermatitis in Mice. PLoS ONE 11(1): e0144871
- Brayton, C. 2006. Spontaneous diseases in commonly used mouse strains. In: The Mouse in Biomedical Research. 2 ed. Volume II – Diseases. Fox JG, Barthold S, Davisson M, Newcomer CE, Quimby FW, Smith A, editors. New York: Academic Press, Inc. p 648.
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- Mufford T, Richardson L. 2010. Nail trims versus the previous standard of care for treatment of mice with ulcerative dermatitis. JAALAS. 48(5): 532-640.
- Neuhaus B, Niessen CM, Mesaros A, Withers DJ, Krieg T, Partridge L. 2012. Experimental analysis of risk factors for ulcerative dermatitis. Experimental Dermatology. 21: 710-720.
- Williams L, Csaki LS, Cantor RM, Reue K, Lawson GW. 2012. Ulcerative dermatitis in C57BL/6 mice exhibits an oxidative stress response consistent with normal healing. Comp Med. 62(3): 166-171.
- Williams-Fritze MJ, et al.2011. Maropitant Citrate for Treatment of Ulcerative Dermatitis in Mice with a C57BL/6 Background. JAALAS 50(2): 221-226