Feline Information Bulletin Cornell Feline Research Laboratory Number 3, February 1978

nonexistent for the cat. Bacterial skin always cause one to suspect a Feline Skin diseases of the cat include abscessation- concurrent feline leukemia virus cellulitis, atypical mycobacterial (FeLV) infection. FeLV infection may Disorders infection, dermatophilosis (strepto- be associated with suppression of the thricosis), actinomycosis, nocardiosis, cat's immune responses and predis­ Danny W. Scott, D.V.M., and tuberculosis. Only the first two pose it to recurring infections of d .a .c .v .i .m . will be discussed here. many organ systems. Prevention of AC would necessi­ Abscessation-cellulitis (AC). AC is one tate avoidance of cat fights; it has of the most common of feline skin been shown that castration of male Feline dermatology is in its infancy; disorders and may affect any breed, cats, even in adulthood, is 80 to 90 much information has been gathered sex (but especially intact males), or percent effective in preventing in the last five to ten years. This age. AC is almost always a secondary fighting. bulletin will present a brief overview occurrence to bites and scratches of the current status of some of the from cat fights, the most common Atypical mycobacterial infection (FL, more common feline skin disorders areas affected being the face, limbs, leprosy). Feline leprosy (FL) is caused and attempt to point out where base of the tail, and back. The bacteria by bacteria that are thought to be research is sorely needed. In a few involved are invariably those that mainly soil and water inhabitants and skin disorders, such as abscesses and normally reside in the cat's mouth cause infection by wound contamina­ nutritional steatitis, the cause, (Pasteurella multocida, Streptococcus spp., tion. There are apparently several diagnosis, treatment, and even pre­ Fusiformis spp.). species of mycobacteria involved. A vention are well established. In other An abscess is an infection charac­ cat of any breed, sex, or age may be disorders, such as dermatophytosis terized by a focal accum ulation of pus. affected. and flea allergy, the cause and Cellulitis is a diffuse infection of the Signs of FL include one to multiple diagnosis are fairly straightforward, skin characterized by swelling, pain, nonpainful, nonpruritic (nonitching) but many questions about treatment and failure to "come to a head." Signs nodules (tumors) in the skin that and prevention remain unanswered. of AC are quite variable, from the frequently ulcerate. These lesions In yet another group of cutaneous classic abscess (swelling, heat, pain, may occur anywhere on the body. diseases, such as the eosinophilic eventual drainage) to swelling with-, Regional lymphadenopathy may be granuloma complex and feline endo­ out heat or pain to severe pain present, but the cat usually appears crine alopecia, diagnosis is easy and without much swelling. Affected cats healthy otherwise. control is possible with maintenance will often have fevers, elevated white Diagnosis is made by history, drug regimes, but little is known blood cell counts, depression, leth­ physical, and surgical biopsy. The concerning cause and prevention. argy, and lack of appetite. AC must be different mycobacteria involved are treated with respect, as more serious very difficult to culture, and culturing Bacterial Skin Diseases infectious sequelae may include requires special laboratory tech­ Normal skin is a good culture medium pyothorax, otitis media, osteomy­ niques. Treatment is by surgical for bacteria. Bacteria are normally elitis, sinusitis, rhinitis, septic removal. To date, drug therapy with found on the surface of the skin and arthritis, and bacteremia. various antileprosy and antituber­ m the outer portions of hair follicles Diagnosis is usually made by culosis agents used in man has been down to the depth of sebaceous gland history, physical examination, and disappointing in the cat. ducts. Although knowledge concern­ surgical drainage. Treatment usually Much remains to be learned about ing normal and abnormal skin bac­ includes surgical drainage and topical FL. It has only been recently recog­ teria in m an is quite advanced, it is and systemic antibiotics. Recurrent, nized in the United States, and minimal for the dog and virtually chronic, or poorly healing AC should questions as to the exact mode of transmission, the number and types lesions or the entire body), topical indirect contact and may also produce of mycobacteria involved, and the fungicide dips (such as lime sulfur or transient skin disease in humans. No relationship to murine and human captan) once weekly, and griseofulvin breed, sex, or age predilections of leprosy must be answered. orally. Such therapy is continued these parasites are known. until clinical or mycologic cure is Signs of C are quite variable and in­ achieved (four to twelve weeks). Gris­ clude seborrhea sicca, miliary eczema, Fungal Skin Diseases eofulvin should not be given to preg­ and the asymptomatic carrier. In the Fungi may be responsible for super­ nant queens, as teratogenicity (birth case of the cat with asymptomatic ficial (as is most common) or deep defects) may result. Treatment of infection, the only clue may be the infections of the skin. Fungal skin exposed animals should include iso­ red, itchy dermatitis in its owner. diseases of the cat include dermato- lation, dips, and griseofulvin for two Diagnosis includes history, physi­ phytosis, pityrosporiasis, sporotri­ weeks. If no signs of disease have cal examination, skin scrapings, and chosis, mycetoma, phaeohyphomy­ occurred, drug therapy may be fecal flotation. Treatment includes (l) cosis, blastomycosis, coccidioidomy­ stopped and isolation continued. the affected cat (parasiticidal dips, cosis, cryptococcosis, and histo­ Treatment of the environment in­ shampoos, or powders, weekly for plasmosis. Only dermatophytosis will cludes weekly thorough vacuuming three to four weeks), (2) in-contact be considered here. and emptying or discarding vacuum animals (same), and (3) the environ­ bag and weekly fungicidal washings ment (thorough vacuuming, parasiti­ Dermatophytosis (D, dermatomycosis (iodophors, formaldehyde, Clorox, cidal washes, weekly for three to four tinea, ringworm). D is one of the more etc.) where feasible (floors, walls, weeks). Parasiticidal agents contain­ common feline skin disorders and is kennels, etc.). Every infected hair that ing almost any of the organophos- caused by a number of fungi, the most falls off the cat and comes to rest in phates or the chlorinated hydro­ common of which are Microsporum the environment is a source of carbons are to be avoided in cats. canis, Microsporum gypseum, and Tri­ infection for over a year. Prevention requires avoiding contact chophyton mentagrophytes. M. canis is the Important questions concerning with infected animals, which may be most common cause of feline D, and therapy and prevention remain. problematical in the outdoor cat. the main source of infection is carrier There is currently much confusion cats; M. gypseum is found in soil, and T. and concern over what the effective Otodectic mange (OM, ear mites). O M is mentagrophytes is carried by rodents. dose and frequency of administration caused by the mite Otodectes cynotis. These fungi are transmitted by direct of griseofulvin in cats should be. This mite infects cats and dogs and and indirect contact (environment, Preliminary studies in other animal may produce transient dermatitis in fomites, air, etc.) and are readily species suggest that vaccination humans. OM is quite contagious, by passed from animal to animal, and against D may be beneficial. To date, direct or indirect contact. from animal to man. A cat of any prevention is possible only by avoid­ Signs of OM include (l) otitis breed, sex, or age (but especially ing infected animals and humans. externa (external ear infection), with young cats) may be affected. resultant head shaking, ear scratch­ Signs of D are extremely variable, ing, creation of sores and ulcers which is often confusing and mis­ around the head and ears, and a leading. Skin lesions vary from the Parasitic Skin Diseases discharge from the ears, which may classic ringworm (circular area of Parasites are one of the more vary from a coffee-ground appear­ alopecia, scaling, crusting, with or common causes of skin disease in the ance to a waxy brown; (2) seizures without inflammation) to pigmentary cat. These parasites may be on the (unusual severe cases); and (3) the changes of skin or hairs to broken skin (ectoparasites) or within the asymptomatic carrier. hairs to seborrhea sicca ("dandruff") body (endoparasites). Parasitic skin Diagnosis includes history, physi­ to miliary eczema to the asympto­ diseases in the cat include cheyletiel- cal, otoscopic examination, and matic carrier. Lesions may occur losis, demodectic mange, trombicu- microscopic examination of ear anywhere but are especially common lidiasis (chiggers), otodectic mange swabs. Treatment must include (l) on the face, head, and extremities. (ear mites), fleas, pediculosis (lice), the affected cat (miticidal otic prepa­ Diagnosis is by history, physical, ticks, cuterebriasis (grubs), myiasis rations, twice weekly for four weeks, and fungal culture. The Woods light (maggots, "fly-strike"), and intestinal and flea powder, total body, once (ultraviolet light) examination and parasitism. Only a few of these will be weekly for four weeks); and (2) in­ KOH preparation are quick, easy, discussed here. contact animals (same). It must be inexpensive diagnostic aids but offer remembered that ear mites reside on no better than 50 percent accuracy. Cheyletiellosis (C, ‘‘walking dandruff"). C the skin, as well as in the ears. T reatm ent m ust include (1) the is caused by three species of a fairly Environm ental contam ination is not a affected animal, (2) in-contact ani­ large mite: Cheyletiella parasitivorax, C. problem with this parasite. Preven­ mals, and (3) the environment. blakei, and C. yasguri. These mites may tion requires avoiding infected ani­ Treatment of infected animals in­ also be found on dogs and rabbits. mals. Flea and tick collars and cludes isolation, clipping (single They are transmitted by direct and medallions are of no benefit in OM. Fleas and flea allergy dermatitis (FAD). Flea collars and medallions are helpful Allergic Skin Diseases but do not prevent fleas from Flea infestation and FAD are probably Allergic skin diseases of the cat tbe most common cause of skin jumping on cats and biting them. include urticaria-angioedema ("hives"), disease in the cat. Several species of Thus, for the cat with FAD, they are food allergy, allergic contact derma­ fleas may infect cats, including of minimal benefit. Prevention, then, titis, drug eruption (drug allergy), flea Ctenocephalides felis (cat flea), C. canis is the outstanding problem as con­ allergy dermatitis, and those asso­ (dog flea), and Pulex irritans (hum an cerns fleas and FAD. Research on flea ciated with intestinal parasitism. Flea flea). Any of these fleas may attack repellents and hyposensitization allergy (the most common cause of cats, dogs, and humans. Transmis­ (allergy shot) products is urgently allergic dermatitis in cats), and sion is by direct and indirect contact. needed. Already, reports of flea intestinal parasitism have already No breed, sex, or age predilections of populations resistant to most avail­ been discussed. The others are fleas are known. able pesticides are surfacing from uncommon to rare, and only food Signs of the flea infestation are around the country. allergy will be discussed. variable. Cats with simple flea infestation may exhibit minor pru­ Pediculosis (lice). Lice are an uncom­ Food allergy (FA). FA is an uncommon ritus (itching) and dermatitis or no mon cause of skin disease in the cat, cause of skin disease in the cat. signs at all, in spite of harboring m any being more common in areas of Virtually every conceivable foodstuff fleas. The cat with FAD, however, crowding and socioeconomic depres­ has been reported to cause FA in the has developed an allergy to flea saliva, sion and where sanitation and clean­ cat. Over 70 percent of the cases of and the bite of a single flea can liness are poor. The cat louse is Felicola feline FA have been consuming the Produce pruritus and dermatitis subrostratus and appears to be quite offending diet for over two years lasting for twenty-four to ninety-six host-specific. Transmission is by prior to the onset of signs. No breed, hours. FAD usually results in papules direct and indirect contact. No breed, sex, or age predilections have been (little red bumps), scabs, excoria­ sex, or age predilections exist. noted. tions (self-mutilation), alopecia (hair Signs of lousiness are variable, Signs include (1) miliary eczema, (2) loss), licking, biting, and scratching including (1) mild to moderate itching pruritic, ulcerative dermatitis about around the neck, back, posterior and without skin lesions, (2) miliary the head and neck, (3) pruritus medial thighs, and the abdomen eczema, and (3) the asym ptom atic without skin lesions, and (4) urticaria- (miliary-eczemalike). These signs carrier. These signs tend to be most angioedema. Gastrointestinal signs tend to occur during the spring, severe during cold weather. (vomiting or diarrhea) are rare. summer, and fall in the northern Diagnosis is by history and physi­ Diagnostic techniques include United States and year-round in the cal examination. Treatment includes history, physical, elimination diet, South. (1) the affected cat (flea shampoos or and test-meal feedings. Elimination Diagnosis includes history, physi­ powders weekly for four weeks); (2) diets must consist of foods that the cal examination (fleas or flea dirt), in-contact cats (same); and (3) the cat does not eat with any regularity. and finding tapeworm segments in environment (thorough vacuuming, One cannot simply switch to a the cat's stool, haircoat, or environ­ sprays). Lice do not usually persist in different brand, flavor, or consis­ ment. Treatment must include (1) the the environment for more than three tency of cat food. Boiled chicken, affected cat (parasiticidal shampoos to seven days. long-grain rice, and water are often and powders, weekly for at least four used. Salt, preservatives, food color­ weeks; cortisonelike drugs to sup­ Intestinal parasitism (IP). Many of the ings, and other condiments must be press the allergic reaction for seven to intestinal parasites of cats may avoided. Signs usually improve ten days); (2) in-contact cats and dogs occasionally be associated with skin dramatically within seventy-two (same); and (3) the environm ent disease. No breed, sex, or age hours after the offending diet is (thorough vacuuming and vacuum predilections of these parasites are discontinued. bag disposal, sprays, "bombs," pro­ known. Signs may include (1) itching Treatment includes introducing fessional exterminators). It is im­ without skin lesions, (2) seborrhea single dietary items, seven days at a perative to address vigorous therapy sicca, and (3) miliary eczema. Intes­ time, until variety and economy are to the environment, as the flea spends tinal parasites associated with such achieved. Daily vitamin and mineral 90 percent of its lifetime off the host in skin disorders have included round­ supplements should also be pre­ the host's environment. Unfed fleas worms, hookworms, and tapeworms. scribed. will survive for months in homes. How these parasites produce skin Prevention, at present, can be disease is not known, but allergic accomplished only by avoiding in­ reactions are suspected. Diagnosis is Autoimmune Skin Diseases (ASD) rested animals and environments. by history, physical, and fecal flota­ Autoimmune skin diseases (ASD) Obviously, this is impossible for tion (one to three samples). Treat­ are those in which the animal begins °utdoor animals, as there is no known ment includes eliminating the para­ to attack and destroy its own skin. 'vay of eliminating fleas outdoors. site involved. These disorders tend to be quite severe, and their causes are un­ abnorm alities in sebaceous (oil) and physical examination. Treatment is known. The diagnosis of ASD re­ apocrine (sweat) gland function. dependent on the stage at which FSD quires rather sophisticated labora­ Thus, SSDs are often referred to as is recognized and may include (1) tory testing, and, thus, these entities seborrhea sicca (dry and flaky), and keeping the cat indoors between 8:00 are only now beginning to be recog­ seborrhea oleosa (greasy and flaky), a.m. and 4:00 p.m., (2) topical nized in cats. Examples of ASD and seborrheic dermatitis (greasy, sunscreens, (3) cortisonelike drugs, recognized in cats include pemphigus flaky, red, inflamed, and itchy). and (4) amputation of the pinnae. vulgaris, pemphigus foliaceus, and The important question to be FSD must be recognized and treated lupus erythematosus. These diseases answ ered w hen one is presented w ith early, as neglected cases can undergo are undoubtedly rare, and only time a cat having SSD is w hether the malignant transformation, especially and improved technology will allow disorder is primary (cause unknown) into squamous cell carcinoma. understanding of their importance. or secondary (associated with some other disease). Secondary SSD may Psychogenic Skin Disease be seen with (l) endocrine skin Endocrine (Hormonal) Skin Diseases diseases (FEA, hypothyroidism , hy- Feline hyperesthesia syndrome (FHS, neuro- Endocrine skin diseases of the cat peradrenocorticism), (2) parasitic skin dermatitis). FHS is usually seen in the include feline endocrine alopecia, diseases (cheyletiellosis, lice, fleas, Siamese, Burmese, Abyssinian, Hi­ hypothyroidism, and hyperadreno- intestinal parasites), (3) fungal skin malayan, and crosses thereof. No sex corticism (Cushing's disease). These disease (dermatophytosis), (4) dietary or age predilections are reported. FHS diseases are uncommon to rare. Only deficiencies (protein, fats, vitamin A), may be caused by any stimulus that feline endocrine alopecia will be (5) liver disease, (6) intestinal malab­ would cause a cat to constantly worry discussed. sorption, (7) autoimmune skin dis­ a particular area of skin, such as ease (pemphigus foliaceus), and (8) parasites, allergy, anal sac problems, Feline endocrine alopecia (FEA). The environment (high ambient tempera­ joint, muscle, or bone pain, matted cause of FEA is unknown, although its ture with low humidity, excessive fur, foreign matter in the coat, etc. exclusive occurrence in neutered cats bathing or powdering). However, in over 90 percent of the and its good response to sex hormone Diagnosis includes history, physi­ cases, FHS is precipitated by psycho­ therapy suggest that it is related to cal examination, and testing for genic trauma and displacement sex hormone deficiency or imbalance. causes of secondary SSD. Treatment phenomena. Examples would include Ninety percent of the cases are seen of secondary SSD is directed at the a new pet, baby, or guest in the home; in castrated males, the other 10 underlying cause. Treatment of a favorite family member leaving the percent in ovariohysterectomized primary SSD is symptomatic (anti- household; or the cat being boarded females. No breed or age predilec­ seborrheic shampoos as needed) and or hospitalized. tions are reported. continued for the life of the cat. Coal Signs include either (l) localized Signs include alopecia affecting the tar shampoos must not be used on areas of alopecia, excoriation, ulcera­ abdomen, genital region, and poste­ cats. tion, and crusting, or (2) localized rior and medial aspects of the thighs. Feline acne and stud tail are other, areas of alopecia without skin lesions. Hairs in the affected areas can be localized forms of SSD in the cat. Favorite areas include the abdomen, easily epilated. flank, medial thigh, back, and front Diagnosis includes history, physi­ leg. cal examination, and response to Diagnosis includes history and Actinic Skin Disease therapy. Treatment methods include physical examination. An exhaustive (FSD, Photodermatitis) injections of the androgen-estrogen history is mandatory in these cases, or progesteronelike drugs as needed Feline solar dermatitis (FSD). FSD is for only if the inciting cause can be or maintenance doses of megestrol caused by ultraviolet light (sunburn) detected and remedied can the FHS acetate (Ovaban). in susceptible cats. White cats or cats ever be cured. Treatment includes (1) As may be noted from the above with white ears, noses, and eyelids correcting the underlying cause, and discussion, research is needed on the are predisposed. No sex or age (2) antianxiety drugs, such as pheno- cause and prevention of FEA. Like­ predilections are reported. FSD barbital or progesteronelike drugs wise, no diagnostic laboratory test is occurs most commonly in the south­ (Ovaban, for instance). available. Studies of the blood and ern regions of the United States. urine androgen-estrogen levels in Signs include reddening of the tips Congenital-Hereditary Skin Diseases of the ears, and occasionally the nose normal and FEA cats might be (CHSD) extremely enlightening. and eyelids, and then progress to alopecia, scaling, ulceration, and CHSD of the cat include alopecia crusting. Latter stages of FSD are universalis (Sphinx cat), cutaneous Seborrheic Skin Diseases (SSD) accompanied by head shaking and ear asthenia (Ehlers-Danlos syndrome), Seborrhea refers to abnormal skin scratching. dermoid cysts, and epitheliogenesis keratin production, with or without Diagnosis includes history and imperfecta. These diseases are rare. Nutritional Skin Diseases (NSD) all breeds, sexes, and ages. Although acid deficiency. Depending on what NSD described in the cat include the cause of this group of skin lesions area of the country you are in, these deficiencies of iodine (hypothyroid­ is unknown, one of the types, the entities may account for 40 to 85 ism), vitamin A (seborrhea), ribo­ eosinophilic ulcer ("rodent ulcer"), is percent of all MEC cases. Obviously, flavin, biotin (miliary eczema), vita­ frequently associated with concur­ depending on geographic location and min E (steatitis), fatty acids (sebor­ rent FeLV infection. cause, MEC may be seasonal or rhea, miliary eczema), and protein Signs include (1) one or multiple nonseasonal. (seborrhea). These are extremely rare nonpruritic ulcers, especially on the Diagnosis includes history, physi­ upper lip (eosinophilic ulcer), (2) one to nonexistent today, because cats are cal, and tests for known causes of usually fed good commercial diets. or multiple raised, red, pruritic MEC. Again, depending on where plaques, especially on the abdomen, you live, 15 to 60 percent of the cases flank, or medial thigh (eosinophilic of MEC may be idiopathic, of un­ Physicochemical Skin Diseases plaques), and (3) one or multiple known cause. (PCSD) linear, raised, firm, nonpruritic, Treatment of MEC of known cause PCSD reported in the cat include yellowish pink lesions, especially on involves specific therapy for that contact dermatitis (kerosine, flea the posterior thighs and in the mouth cause. Idiopathic MEC, however, collars, other chemicals and irritants), (linear granuloma). responds well to only one type of decubital ulcers (bedsores), frostbite, Diagnostic techniques include his­ drug, progesteronelike compounds burns, and thallium poisoning. These tory, physical examination, and (such as Ovaban). Unfortunately, disorders are rare in cats. biopsy. Treatment includes corti­ maintenance therapy usually needs to sonelike drugs or progesteronelike be continued for the life of the cat. Neoplastic Skin Diseases (Tumors) drugs (such as Ovaban). About 25 to Many questions need to be an­ 50 percent of these cases will require swered about idiopathic MEC. What Skin tumors are common in cats; in long-term maintenance therapy. causes it? Is there a specific diagnostic fact, the skin is the second most Obviously, research is desperately test that could be used for it? Why are common site for cat tumors. Most cat needed on the cause of EGC, espe­ progesteronelike drugs so effective, skin tumors are malignant. Thus, cially the viral and immunological and how might this shed light on the they should be subjected to exfolia­ aspects of it. cause? tive cytology or surgical biopsy as soon as possible. Therapy may include surgery, radiation, or drugs. Miliary eczema complex (MEO. MEC is a common group of diseases that result in a skin disorder characterized by Further Information Feline Skin Diseases of papules, crusts, excoriations, alope­ Undetermined Cause For more information about the work cia, and pruritus. MEC usually begins of the Cornell Feline Research These include the eosinophilic granu­ over the back and may spread to Laboratory, write to loma complex, nodular panniculitis, involve the entire body. MEC may Cornell Feline Research Laboratory and some diseases in the miliary affect cats of any breed, sex, or age. eczema complex. Known causes of MEC include flea New York State College of allergy dermatitis, pediculosis, chey- Veterinary Medicine Eosinophilic granuloma complex (EGO. letiellosis, intestinal parasitism, Cornell University EGC is a group of common, apparent­ dermatophytosis, food allergy, drug Ithaca, New York 14853. ly related skin lesions seen in cats of eruption, biotin deficiency, and fatty

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