 usually signifies underlying internal disorder
Type of skin lesion Animals affected Diagnosis/Treatment Alopecia Hamsters, gerbils, guinea pigs Skin scraping, fungal culture, skin biopsy treat for subsequent diagnosis Scaling without pruritis Hamsters gerbils, guinea pigs Skin scraping, fungal culture, skin biopsy treat for subsequent diagnosis Scaling with pruritis Hamsters gerbils, guinea pigs Bathe with an antipruritic or mild antiseborrheic shampoo labeled for cats and/or give ivermectin (200 400m g/kg SC in two treatments 10 14 days apart). Ivermectin treatment may be diagnostic for mange if the lesions resolve. Abscesses (submandibular or cervical lymphadenitis) Guinea pigs Caused by Streptococcus zooepidemicus.
Treatment: Lance abscess or remove lymph nodes; follow with systemic antibiotics (trimethoprim-sulfamethoxazole, trimethoprim-sulfadiazine, or enrofloxacin).
Mange Guinea pigs (Demodex caviae or Trixacarus caviae, a sarcoptid mite)
Gerbils (Demodex spp.)
Hamster (Demodex spp., Notoedres notoedres, Notoedres cati)
*Trixacarus mange: whole body lime-sulfur dips (once a week continuing for 2 weeks after a negative skin scraping) or ivermectin (200 400 m g/kg SC every 10 14 days until skin scraping is negative).
*Demodectic mange: Amitraz (MitabanÒ ) (250 ppm as a whole body dip, once a week, continuing for 4 weeks after a negative skin scraping).
*Notoedric mange: whole body lime-sulfur dips (once a week continuing for 2 weeks after a negative skin scraping) or ivermectin (200 400 m g/kg SC every 10 14 days until skin scraping is negative).
**Dermatophytosis in rodents is potentially zoonotic
All pet rodents (Trichophyton mentagrophytes) Dx: Fungal culture or biopsy
Whole body treatment: 2% lime-sulfur or 1% chlorhexidine, topical application
Local lesions: use topical creams (TresadermÒ or ConofiteÒ )
Systemic treatment: Give griseofulvin 25 mg/kg PO SID until fungal culture is negative. (Use only if needed; do not use in pregnant animals.)
Bacterial dermatitis All pet rodents, especially those housed with other rodents Usually Staphylococcus spp.
Bite wounds; primary skin infections possible.
Treatment: Trimethoprim-sulfamethoxazole, trimethoprim-sulfadiazine, or enrofloxacin. (Avoid antibiotics with predominantly gram-positive spectrum.)
Pododermatitis Guinea pigs Staphylococcus aureus.
Enlarged, edematous, and erythematous food pads, with crusting, hemorrhage, or ulceration. Advanced cases have a poor prognosis due to difficult treatment and occurrence of systemic amyloidosis from chronic infection.
Treatment: topical antibiotic rinses (diluted chlorhexidine or diluted povidone-iodine), systemic antibiotics (trimethoprim-sulfamethoxazole or trimethoprim-sulfadiazine at 30 mg/kg PO BID; or enrofloxacin 10 mg/kg PO BID), and soft, frequently-changed bedding.
Non-infected wounds may be encouraged to epithelialize by using BioDres or TegadermÔ wound dressings.
Lice Guinea pigs Direct observation of adults or nits or by acetate tape impression.
Treatment: Use pyrethrin or pyrethroid sprays (labeled safe for cats), or 2% lime-sulfur dips, or ivermectin (200 400 m g/kg SC every 10 14 days until there is no evidence of infestation).
Staphylococcal nasal dermatitis
Alopecia on the nose and muzzle and no other lesions. Caused by rubbing the cage or burrowing or excess secretion or accumulation of the harderian gland secretions.
Treatment: place pet in a smooth sided cage with soft bedding (shredded newspaper), decrease humidity (normal is 40 - 50%).
Staphylococcus spp. infection
Alopecia with erythema, oozing, crusting, scaling, abscessation, fistulation, or ulceration.
Treatment: Give trimethoprim-sulfamethoxazole or trimethoprim-sulfadiazine at 30 mg/kg PO BID; or enrofloxacin 10 mg/kg PO BID
Skin cancers Rare in all pet rodents Definitive diagnosis made by biopsy.
Signs: Solid tumors or alopecia.
Tumors are common. Rats develop tumors more often than do mice or other pet rodents.
Most common tumors seen:
Rats: mammary gland fibroadenomas
Mice: mammary adenocarcinomas
Guinea pigs: trichofolliculomas (a solitary l