| Condition | Description | Symptoms | Diagnosis | Treatment |
|---|
Allergic and irritant contact dermatitis | An allergic reaction following exposure to antibiotics applied to the skin; metals such as nickel; materials such as rubber, wool, and plastic; chemicals such as dyes and carpet deodorizers; or inflammation caused by irritating substances such as poison ivy. Generally requires multiple exposures. | Red skin and small bumps or blisters on the areas of skin that are sparsely haired and directly exposed to the offending substance; itching; hair loss in chronic conditions | Patch test, exclusion trials | Restrict exposure to the allergen or contact irritant in the cat's environment; steroids, antihistamines |
| Alopecia areata | Thought to be an autoimmune disorder | Patches of cat hair loss especially on head, neck, and body; no itching | Microscopic examination of hairs; biopsy | Usually recover spontaneously |
| Apocrine sweat gland cyst | Rare in cats | Single, round, smooth nodules with no hair; may appear bluish; usually filled with a watery liquid; most common on head, neck, and limbs | Physical exam; biopsy | Surgical removal is optional |
Atopy (allergic inhalant dermatitis) | Allergic reaction to something the cat inhales such as pollen, house dust mites, and mold | Licking of feet, inflamed ears, itching, redness, and cat hair loss; sometimes development of infection or hot spots | Intradermal or serologic (blood) testing for allergies | Reduce exposure to allergen (what the cat is allergic to), steroids, fatty acid supplements, biotin, antihistamines, shampoos, immunotherapy |
| Bacterial infection (pyoderma) See Folliculitis | Often occurs as a result of another condition such as a parasitic, allergic, or hormonal conditon | | | |
| Chemotherapy | Loss of hair due to chemotherapy is a concern for cat owners | Cats lose guard hairs so coat becomes soft and fuzzy; may lose whiskers | History | None, hair will regrow after chemotherapy discontinued; may regrow in a different color or texture |
Cheyletiella (rabbit fur mite) mange | Infection with the Cheyletiella mite | Itching, scaliness; some cat hair loss, if severe | Skin scraping and microscopic examination - the mite is often very difficult to find | Pyrethrin |
| Congenital hypotrichosis | Congenital lack of hair | Kittens born with little or no hair; any hair they are born with is lost by 4 months of age | Physical exam; biopsy | None |
| Cushing's disease (hyperadrenocorticism) | Caused by an increase in corticosteroids in the body - either due to increased production by the body or as a side effect of high doses or prolonged therapy with corticosteroids | Cat hair loss, thinning of skin, hyperpigmentation, easy bruising, seborrhea, comedones (black heads); lethargy, increased thirst and urination, pot-bellied appearance | Adrenal gland function tests, urinalysis, chemistry panel, CBC | If due to glandular tumors, selegiline, o,p-DDD (Mitotane), or surgical removal of tumor; if due to high steroid doses, withdraw use of steroids slowly |
Demodectic mange | Infection may be localized or generalized; the generalized form occurs in cats who have a deficient immune system | Cat hair loss, scaliness, redness, sometimes itching | Skin scraping and microscopic examination | NO Steroids! Rotenone, dilute Amitraz (Mitaban) dips, lime sulfur dips, ivermectin (off-label use*) |
| Drug or injection reaction | Rare skin reaction to a drug which is inhaled, given orally, or applied topically; more common with penicillins, sulfonamides, and cephalosporins; usually occurs within 2 weeks of giving the drug | Can vary widely and may include itching, hair loss, redness, swelling, papules, crusts, ulcers, and draining wounds | History of being treated with a drug, symptoms, biopsy | Discontinue offending drug; treat symptomatically |
| Erythema multiforme | Hypersensitivity reaction to infections or drugs; may also be caused by cancer or other diseases | Hair loss, 'bull's eye' lesions and vesicles often around mouth, ears, groin, and axilla; in some instances, ulcers develop; depression, fever | History, clinical signs, rule out other diseases causing similar signs; skin biopsy | Treat or remove underlying cause |
| Facial (preauricular) alopecia; normal hair loss above the eye | Normal decreased density of hair between the eye and ear | This decreased density of hair starts when cats are 14 to 20 months old; more prominent in short-haired, dark colored cats | No diagnostics necessary unless signs of skin disease are present such as redness or scaling | None - normal |
| Feline acquired symmetrical alopecia | Rare; originally called 'feline endocrine alopecia'; cause unknown | Symmetrical hair loss on back of thighs, abdomen, and genital areas; hair easily pulls out; no itching | Skin biopsy; tests to rule out other causes of hair loss | None |
Flea allergy dermatitis (flea bite hypersensitivity) | Severe reaction by the cat to the saliva of the flea | Intense itching, redness, hair loss papules, crusts and scales; sometimes development of infection or hot spots | Presence of fleas; reaction to intradermal testing | Flea Control in the environment and on the cat; steroids and antihistamines for the itching |
| Folliculitis | Infection of the hair follicles; symptoms usually appear on face, neck, and head | Pustules develop in the hair follicles and open and form crusts; may itch and develop hair loss | Skin scraping; culture; biopsy; look for underlying condition such as allergy or FIV | Antibiotics, usually for 3-4 weeks; treat any underlying condition |
Food allergies | Allergic reaction to something in the diet | Licking of feet, inflamed ears, itching, redness, and hair loss; sometimes development of infection or hot spots | Food elimination trials | Change in diet |
| Granulomas | May be due to infections; the body's reaction to foreign material such as plant material (e.g., foxtail) and suture material; other constant irritation; or unknown causes | Solid, firm nodules of varying sizes; those due to foreign bodies often have draining tracts; may develop hair loss, ulcers, and secondary infections | History, clinical signs, biopsy, surgical exploratory | Surgical removal of the foreign body (in the case of plant material, tracts may be extensive and require major surgery); antibiotics if infected; treat any other underlying cause |
| Hair loss during pregnancy and nursing ('blowing her coat,' telogen effluvium) | Excess shedding that can also occur in other stressful circumstances such as illness or surgery | Sudden and widespread hair loss | History, clinical signs | Treat any underlying condition; hair will grow back |
| Hyperthyroidism | Approximately 1/3 of cats with this disease will have skin lesions; caused by excess secretion of thyroid hormone | Hair loss; hair easily pulled out; seborrhea; cats may overgroom and cause 'hot spots' | Physical exam; blood testing for thyroid hormones | Remove part of thyroid; radioactive iodine therapy; methimazole |
| Injection site alopecia | Hair loss at the site of an injection of a medication or vaccine; skin may become thickened; in cats, ulcers may develop | Hair loss occurs several months after injection; area may become hyperpigmented | History and physical examination | None; the condition is permanent |
Lice | Infection with several species of lice | Variable: itching, hair loss, crusts, rough hair coat | Finding lice or nits on skin or hair | Pyrethrin, ivermectin (off-label use*) |
Malassezia | Usually follows some other underlying disease | Itching, redness, hair loss, greasy scales; if chronic develop hyperpigmentation | Skin scraping/smear and microscopic examination, culture | Treat underlying disease; oral ketoconazole; miconazole shampoos |
Psychogenic (neurogenic) dermatitis | Self-licking in cats results in self-trauma; possible causes include anxiety, boredom, stress (e.g., new member in household) | Symmetrical hair loss, sometimes ulcers, on abdomen, groin, along the back | Exclude other causes; history important | Relieve underlying cause e.g., anxiety; restrict licking; behavior modifying medication may be necessary |
| Pyoderma-superficial (see Folliculitis) | | | | |
| Ringworm | Infection with several types of fungus | Hair loss, scaliness, crusty areas; some itching | Culture | Miconazole, lime sulfur dips; oral griseofulvin or itraconazole; ringworm vaccine |
| Sebaceous adenitis | Sebaceous glands are destroyed, cause unknown; very rare in cats | Circular areas of crusts and scales on head, ears, and neck; hair pulls out easily, leaving skin exposed | Clinical signs, skin biopsy | Antiseborrheic shampoos, fatty acid supplements; in more severe cases, steroids, retinoids |
| Seborrhea | Can be primary (inherited) or secondary (resulting from other disease processes such as FeLV, FIP, FIV, ringworm, and parasites) | Scales; depending upon the type, may have a dry or oily coat; odor; some scratching; may see hair loss | Blood tests, skin scrapings, etc. to find underlying cause | Treat underlying cause if present; antiseborrheic shampoos; fatty acid supplements |
| Solar dermatosis (sunburn) | Skin reaction to sunlight; more common in cats with white ears | Redness, hair loss, and scaling on nose and ears, later crusts and ulcers | History, breed, physical exam, skin biopsy | Must avoid further sun exposure, especially 9 am - 3 pm; sunblock, steroids |
| Stud tail (tail gland hyperplasia) | A sebaceous gland (on the top of the tail near its base) enlarges; most often occurs in confined, unneutered males | Oily area, hair loss, and crusts on area over gland; may become hyperpigmented | Clinical signs | Castration usually does not resolve the condition; antiseborrheic shampoos, retinoids; if confined, allow cat more freedom |
