Sick hedgehogs with a variety of illnesses, including acariasis, dental problems, pneumonia, gastric ulceration, neoplasia, and hepatic disease, often present with nonspecific clinical signs such as lethargy, weakness, and anorexia. This frequent presentation serves to emphasize the importance of diagnostic testing, even if anesthesia is required.
Cardiovascular and Hematologic Diseases
Dilated cardiomyopathy (see Cardiomyopathies) is common, although the etiology of this disease is not known. Affected hedgehogs are typically ≥ 3 yr old, although it may occur in animals as young as 1 yr of age. Signs include dyspnea, decreased activity, weight loss, an auscultable murmur, ascites, and acute death. Radiographs typically demonstrate varying degrees of cardiac enlargement, pulmonary edema, pleural effusion, hepatic congestion, and abdominal fluid. Pulmonary and renal infarcts may occur in some affected animals. Normal echocardiographic measurements have not been published, but a subjective evaluation of wall motion and chamber size is often sufficient to confirm the diagnosis. Hematologic and biochemical testing are useful to screen for concurrent problems and for monitoring the effects of therapeutic agents. Therapy with digoxin, furosemide, and enalapril may be helpful, but the longterm prognosis for hedgehogs with congestive heart failure is poor.
Saddle thrombus and pulmonary thromboemboli have been observed. Myocardial mineralization and splenic extramedullary hematopoiesis may exist in pet hedgehogs with concurrent diseases; the clinical significance of these lesions is unknown.
Gastrointestinal and Hepatic Diseases
Enteritis may be caused by Salmonella or other bacteria. Salmonellosis in hedgehogs may be clinically silent or may cause diarrhea, weight loss, decreased appetite, dehydration, lethargy, and death. Diagnosis should be confirmed with fecal culture. Although treatment is indicated in animals with clinical signs of disease, owners should be advised of the zoonotic potential and the risks of creating antibiotic resistance. Alimentary candidiasis (Candida albicans) and cryptosporidiosis are other reported infectious diseases. Although numerous species of nematodes, cestodes, and protozoa have been identified in wild hedgehogs, their significance in pets appears to be minimal.
GI obstructions are most often caused by ingestion of rubber, hair, or carpet fibers. Signs include acute anorexia, lethargy, and collapse. Vomiting may be present but often is not. Diagnosis of obstruction is complicated by the fact that gaseous dilation of the GI tract can be a nonspecific finding in ill hedgehogs. A fatal intestinal mesenteric torsion has also been reported. Alimentary inflammation, including esophagitis, gastritis, enteritis, colitis, and gastric ulceration with perforation, has also been seen. Most of these animals had nonspecific signs such as decreased appetite and weight loss; vomiting and diarrhea were not observed.
Diarrhea also can be associated with some commercial diets or inappropriate foods such as milk. GI neoplasia, particularly lymphosarcoma, is relatively common. Other considerations for GI signs include dietary change, toxins, and hepatic disease. Hedgehog digestion does not rely on bacterial fermentation, and there is no evidence of antibiotic sensitivity as is seen in herbivorous mammals.
Hepatic lipidosis is relatively common and may be a sequela of cardiomyopathy, neoplasia, starvation, obesity, toxicosis, pregnancy, or infectious disease. Signs may include lethargy, inappetence, icterus, diarrhea, and signs of hepatic encephalopathy. Treatment for hepatic lipidosis is similar to that in other species. Other important causes of liver failure include primary and metastatic hepatic neoplasia. Hepatic necrosis caused by human herpes simplex virus 1 was reported in a hedgehog that received dexamethasone.
Acariasis caused by (Caparinia spp) is very common. Signs include lethargy, decreased appetite, hyperkeratosis, seborrhea, quill loss, loose quills, and white or brownish crusts (mite droppings) at the base of the quills and around the eyes. Hedgehogs may scratch or rub themselves, but many individuals do not have obvious pruritus. Some animals have subclinical infestations. Diagnosis is confirmed by skin scraping. Treatment consists of ivermectin or a combination of ivermectin and amitraz. All bedding must be removed and cage furnishings disinfected or discarded. During treatment, the cage is lined with paper that must be changed daily. All hedgehogs in the home should be treated concurrently.
Pet hedgehogs may be infested with fleas; shampoo and powder products that are safe for kittens appear to be safe for hedgehogs. Tropical rat mites, Ornithonyssus bacoti, may also cause flaky skin and loss of spines; fipronil spray is an effective treatment.
Dermatophytes (Trichophyton erinacei, T mentagrophytes, Microsporum spp) cause crusting, usually nonpruritic, dermatitis, especially around the face and pinnae. Some infections are secondary to other dermatophathies, such as acariasis or trauma. Diagnosis is confirmed by culturing spines in DTM media. Treatment consists of topical antifungal agents, with systemic griseofulvin or ketoconazole if needed. Lyme sulfur dips may also be used. Other hedgehogs in the home may be subclinically infected, and treatment of all animals is recommended.
Skin neoplasia is common; squamous cell carcinoma, lymphosarcoma, and sebaceous gland carcinoma have been described. Papillomas of suspected viral etiology have been reported; recurrence in other sites after excision is common. Cutaneous and subcutaneous nodules may be also caused by abscesses, mycobacteriosis, and Cuterebra larvae.
Contact dermatitis may result from unsanitary bedding. Cellulitis has been linked to secondary myositis and sepsis; the primary cause in most of these cases was trauma. Allergic dermatitis has been anecdotally described; restricted antigen diets, antihistamines, and glucocorticoids may be helpful. Pruritus may occur with the development of new spines, as occurs in young hedgehogs. Pemphigus foliaceus has been reported; loss of spines, flaking skin, moist erythema, and epidermal collarettes were observed. Dexamethasone injections were reported to be an effective treatment.
Myositis secondary to cellulitis has been reported. Osteoarthritis has also been observed. Fractures occur when a limb becomes entrapped in a wire cage or exercise wheel. Splinting can be performed for distal limb fractures. Surgical correction may also be performed, but any fixation device must be able to withstand the strong rolling-up mechanism. Lameness may be caused by ingrown toenails, arthritis, nutritional deficiencies, pododermatitis, constriction of a foot or digit by fibrous material, neurologic disease, or neoplasia.
Neoplasia in African hedgehogs is very common in both sexes. A variety of tumor types affecting every body system have been reported. The most common tumors are mammary gland tumors, lymphosarcoma, and oral squamous cell carcinoma. The median age at time of diagnosis is 3.5 yr, although tumors may occur in animals as young as 2 yr old. In one survey, > 80% of the tumors were malignant. Proliferative uterine tumors or polyps are common and are associated with vaginal bleeding, hematuria, and weight loss. Ovariohysterectomy allows prolonged survival of hedgehogs with uterine tumors. Some sarcomas have been associated with retroviral infection.
Signs depend on the location and severity of disease, and may include palpable masses, weight loss, anorexia, lethargy, diarrhea, dyspnea, and ascites. Diagnosis is based on cytology or histopathology. Diagnostic imaging and blood testing may be useful in determining the extent of the disease and establishing a prognosis. Treatment generally includes surgical excision and supportive care, although other treatment modalities may be helpful. Not every mass in pet hedgehogs is neoplastic; for example, abscesses, bone cysts, papillomas, and uterine polyps occur.
Neurologic signs, particularly ataxia, may be caused by torpor, demyelination, neoplasia, hepatic encephalopathy, trauma, toxins, infarcts, or malnutrition. Hedgehogs kept in cold (or sometimes excessively high) temperatures may enter a state of torpor or dormancy. In this state, the animal has a greatly diminished response to stimulation, decreased heart and respiratory rates, and possibly increased susceptibility to infection. Dormancy can last for several weeks, during which the animal may have periods of activity with ataxia.
Vestibular signs may be caused by otitis media or central neurologic disease. Hypocalcemia may result from postpartum eclampsia, malnutrition, or for unknown reasons, and usually responds to calcium supplementation. Intervertebral disk disease has been reported.
Demyelinating paralysis (wobbly hedgehog syndrome) occurs in as many as 10% of pet hedgehogs. Onset can occur at any age, but is more common in animals <2 yr old. An early sign is the inability to close the hood. This progresses to mild, intermittent ataxia. The signs gradually increase in severity and include falling, tremors, exophthalmos, scoliosis, seizures, muscle atrophy, self-mutilation, and severe weight loss. The paralysis usually ascends from hindlimbs to forelimbs and usually leads to complete paralysis within 9–15 mo after the onset of signs. Death occurs within 18–25 mo. Appetite is usually normal until the terminal stages, when most hedgehogs become dysphagic. The diagnosis is confirmed at necropsy. Histopathologic lesions include vacuolization of white matter, axonal swelling, degeneration of spinal cord ventral tracts, and axonal and myelin degeneration. Peripheral nerves may also be involved. The etiology is unknown, but a hereditary basis is suspected. Numerous treatments have been attempted without success. Euthanasia is recommended when the quality of life is compromised.
Obesity is common. Healthy hedgehogs should be able to roll up completely, without any fat deposits protruding. Treatment includes reducing high-fat foods, rationing the main diet, and increasing exercise. Weight reduction should be gradual to prevent hepatic lipidosis, and owners should monitor their pet's weight. Nutritional excess or deficiency may occur with unbalanced diets; for example, calcium deficiency may result from a diet consisting mainly of invertebrates.
Hedgehogs are prone to corneal ulcers and other ocular injuries. Diagnosis and treatment are as for other species, although administration of topical medication can be difficult. Blind hedgehogs navigate their captive environments with minimal detriment to their quality of life. Ocular proptosis is relatively common and carries a poor prognosis for viability of the eye.
Oral and Dental Diseases
Oral neoplasia, particularly squamous cell carcinoma, is common in hedgehogs. Dental disease, including calculus, gingivitis, and periodontitis, is also common. If advanced periodontal disease requires extraction of all the teeth, hedgehogs can be maintained on soft food. Tooth fractures and dental abscesses also occur. Actinomyces infection has been reported; anaerobic culture and treatment should be considered for dental abscesses in hedgehogs.
Excessive tooth wear occurs in older hedgehogs, and animals with this condition should be fed a soft diet. Hedgehog teeth do not grow continuously and should not be trimmed. Hedgehogs are susceptible to wedging of hard items (eg, peanuts) against the palate. Stomatitis may occur in males that bite their mates; treatment is with soft food and antibiotics.
Pinnal dermatitis is common; skin crusts, accumulated secretions, and a ragged pinnal margin may be observed. Dermatophytes and acariasis are important causes; other possibilities include nutritional deficiencies, dry skin, seborrhea with hyperkeratosis, and extension of ear canal disease. Ear mites (Notoedres cati) are occasionally seen; signs, diagnosis, and treatment are as for cats (see Otodectic Mange). Bacterial or yeast otitis externa also occurs; these infections are often secondary to acariasis or another cause of chronic inflammation. Signs include purulent discharge, odor, and sensitivity of the face and ear. Otic cytology, skin scrapings, cleansing, and topical antimicrobial/anti-inflammatory therapy are used as for other species. Otitis media/interna can also occur.
Posthitis may be caused by substrate entrapment in the prepuce. Hemorrhagic vulvar discharge is often caused by uterine neoplasia or endometrial polyps. Pyometra and metritis have been reported. Dystocia also occurs and is treated as in other small mammals. Premature births occasionally occur; the prognosis for young without a suckling reflex is poor. Agalactia may be suspected if neonates lose condition within 72 hr after birth. Diagnosis may be confirmed by attempting to express the mammary glands; however, this usually requires anesthesia and may cause the dam to abandon or cannibalize her young. Causes of agalactia include malnutrition, stress, lack of oxytocin, inadequate mammary development in young females, and mastitis.
Predisposing factors for upper and lower respiratory tract infection are sub-optimal environmental temperature; aromatic, dusty, or unsanitary bedding; concurrent disease causing immunocompromise; and aspiration of material from an oral infection. Signs include nasal discharge, increased respiratory noise, dyspnea, lethargy, inappetence, and sudden death. Radiographs, hematologic testing, and culture of tracheal or lung lobe aspirates are useful in diagnosis. Treatment includes antibiotics, nebulization, supportive care, and correction of underlying problems. Differential diagnoses for dyspnea are pulmonary neoplasia and cardiac disease.
Cystitis and urolithiasis occur and may cause changes in urine color, stranguria, pollakiuria, inappetence, and lethargy. Urinalysis with culture and radiographs should be obtained. Renal disease is also common and in many cases may be secondary to systemic disease. Nephritis, tubular necrosis, nephrocalcinosis, glomerulosclerosis, infarcts, polycystic kidneys, neoplasia, and various glomerulonephropathies have been identified. Signs associated with renal disease tend to be nonspecific, although polyuria and/or polydipsia may be noted. Treatment consists of correcting the underlying cause, fluid therapy, and supportive care.
Several strains of Salmonella occur in pet hedgehogs. Many cases of transmission to humans have been documented, particularly in young children. It should be assumed that all pet hedgehogs can carry and transmit Salmonella. Because infected animals may shed intermittently, a negative culture cannot rule out the carrier state. Treatment aimed at eliminating the carrier state is unlikely to be successful and may lead to antibiotic resistance.
Wild African hedgehogs are susceptible to foot-and-mouth disease. To prevent introduction of this disease to the USA, importation of African hedgehogs was banned by the USDA in 1991. Rabies has not been reported in wild or captive African hedgehogs, but the salivation that occurs during anting is occasionally mistaken as a sign of rabies. Human dermatophytosis from pet hedgehogs is also well documented.
Last full review/revision July 2011 by James W. Carpenter, MS, DVM, DACZM; Evelyn S. Ivey, DVM, DABVP