ATIENTALDKaren L Campbell DVM MS DACVIM DACVDProfessor Emerita U - PDF document

ATIENTALDKaren L. Campbell, DVM, MS, DACVIM, DACVDProfessor Emerita, University of IllinoisClinical Professor of Dermatology, University of Missouri Definitions Alopecia = loss o

f hairHypotrichosis = presence of less than the normal amount of hairMost commonly used in reference to congenital disorders Causes of AlopeciaFailure of hair growthEndocrine dis

easeHypothyroidismHyperadrenocorticismSex hormone abnormalitiesGrow hormone deficiencyEctodermal dysplasiaDecreased # hair folliclesHair cycle arrestHereditaryDisease or drugsNut

ritional deficiencies Causes of AlopeciaDamage to hair follicleInfectionsDermatophytesBacteriaParasitesDemodexPeloderaFollicular dysplasiaVascular damageImmunemediated damageNeop

lasiaTrauma First decision = Pruritic?HistorySalivary stainingBroken hairs (other ddx: dermatophytes and follicular dysplasia)Hair in fecesElizabethian collarresponsive Hair Loss

with PruritusARASITES: fleas, sarcoptesnotoedrescheyletiellaotodectespelodera, hookworms, chiggers, lice, etc.LLERGIES: environmental (atopy, contact), dietary, parasitic, drugN

FLAMMATORY: Infectious, Immunemediated, irritantsEUROTIC: Neurogenic, neoplastic, nutritional Non - pruritic Next decision = distribution: (1) localized, (2) patchy (multifocal),

(3) symmetrical or generalized NonPruritic Localized AlopeciaDemodicosisDermatophytosisBacterial infectionsDiscoid lupus erythematosusInjection site reactionContact reactionAlo

pecia areataTractionCicatricialalopeciaIatrogenic (e.g. postclipping) Localized Alopecia:Bacterial Infections Localized Alopecia: Dermatophytosis Common Localized Alopecia: Derm

atophytosis Localized Alopecia: Demodex Common PostInjection Alopecia (Rabies Vaccine)SQ rabies vaccinationSQ depomedrol injectionUsually 23 months postinjection, up to 8 months

in some dogsRabiesVaccine induced Vasculitis & AlopeciaPredisposed breeds:Miniature and Toy Poodles, Bichon Frise, Shih Tzu, Lhasa Apso, Chihuahua, Yorkshire Terrier, Maltese, Ma

nchester Terrier, Silky Terrier, American Eskimo Rabies Vaccine - Induced Alopecia: Pathogenesis Antigenantibody deposits in blood vessels Localized vasculitis impaired blood s

upply to hair follicles (ischemic vasculopathy) atrophy of hair follicles alopecia (usually localized to skin over injection site) Rabiesvaccine induced alopecia: treatmentObserv

ationTopical tacrolimus (0.1%; ProtopicPentoxifylline(20 mg/kg q 812 hrsSurgical excision (must include SQ)Check titers rather than vaccinations Alopecia Areata↑Dachshunds (?)F

ocal or multifocalHead, neck, trunkImmunemediatedAntifollicular antibodies and cytoxic T lymphocytes Alopecia AreataBiopsy“swarm of bees” = lymphocytes and plasma cells surro

unding hair bulbTreatments: topical corticosteroids or tacrolimus Localized Alopecia: TractionHair bows Rubber bands Photo above from pg 196 Small Animal Dermatology: A Color A

tlas PostClipping AlopeciaPlushcoated breedsChow chow, Siberian huskyHairs may not regrow for 12 years after clippingCatagen arrestHistory and r/o other causesTry Melatonin (36 m

g/dog q 12 hr) Pruritic: Patchy (multifocal) alopecia“motheaten” hair coatStaphylococcal folliculitisDermatophytosisDemodicosisDermatomyositisSebaceous adenitis*Endocri

nopathiesAlopecia areata*Follicular dysplasiaCongenital alopeciaPemphigus/SLEEpitheliotrophic lymphoma (CTCL, MF)These may also be diffuse (symmetrical) Patchy Alopecia: Staphylo

coccal Folliculitis (COMMON) Patchy Alopecia: Dermatophytosis Patchy Alopecia: Demodicosis Canine Familial Dermatomyositis Canine DermatomyositisManagement: avoid traumapentoxiph

ylline 20 mg/kg q 8 hrsVitamin E 100400 IU BIDTetracycline + NiacinamideCorticosteroids (prednisolone 0.5 mg/# BID)treat secondary infections, neuter Non - pruritic: Patchy Alope

cia: Sebaceous adenitis Sebaceous AdenitisBreedsStandard poodle (autosomal recessive)Akita Vizsla Samoyed otherAgeyoung to middleaged Sebaceous AdenitisLongcoated dogssymmetrica

l alopecia, scaling, dry coat on dorsum, nose, tail, pinnae, trucklater follicular casts and mattingShortcoated dogs“motheaten”alopeciasecondary pyoderma Sebaceous Aden

itisDiagnoseR/O other diseasesClinical signsSkin biopsyAbsence of sebaceous glands or periadnexal pyogranulomatous inflammation Sebaceous AdenitisTreatmentFollicle flushing shamp

oos (Ethyl lactate)Moisturizers (“soakoil treatment”)Isotretinoin(1 mg/kg)Vitamin A (1000 IU/kg)Tetracycline + NiacinamideCyclosporine 5 mg/kgTreat secondary infections

Client education: goal is to minimize symptoms; no cure, is hereditary Congenital HypotrichosisMultifocal forms due to ectodermal defectAutosomal recessive or Xlinked recessiveA

genesis of hair follicles in affected areasProtection from uv light damage neededMore generalized forms will be discussed under symmetrical alopecia Patchy Alopecia: Pemphigus Fo

liaceous Lesions may be multifocal or generalizedDiagnose with cytology & skin biopsy Patchy Alopecia: Cutaneous T cell Lymphoma Hair loss may be localized, multifocal or general

ized; biopsy for diagnosis Nonpruritic Symmetrical AlopeciaHereditaryCongenital alopeciaDermatomyositisPattern baldnessCyclic flank alopeciaColor dilution alopeciaAlopecia X?Misc

ellaneousFeline symmetric alopeciaTelogenanagendefluxionOften generalized (Diffuse)Endocrine HypothyroidismHyperadrenocorticismSex hormone imbalancesAlopecia X?Pituitary dwarfism

InfectiousDemodecosisDermatophytosisNeoplasticCTCLParaneoplastic alopecia Endocrine Alopecia: HypothyroidismCommon DisorderLymphocyctic thyroiditisMany breed predispositionsIdiop

athic thyroid atrophyIatrogenic (sulfa antibiotics, other drugs, surgery) Endocrine Alopecia: HypothyroidismCommon signsThin, dry haircoat, scalingFailure of hair regrowth after

clippingSecondary infectionsWeight gainLethargy, heat seekingDiagnosisHistory and physical examTT4, fT4, cTSH, TSH stimTreatmentT4 supplementationMonitor for therapeutic levels E

ndocrine Alopecia: HyperadrenocorticismCommon in dogs, uncommon in catsPredisposed breedsDachshunds, Boxers, Boston Terriers, poodlesCausesIatrogenicBilateral adrenal hyperplasia

Excessive ACTH production from pituitaryAdrenocortical tumor Endocrine Alopecia: HyperadrenocorticismClinical signsPU/PD/PP/PantingMuscle lossPendulous abdomenThin skin, hair lo

ssCalcinosis cutisComedonesHyperpigmentationEasy bruisingSecondary infectionsmany others Endocrine Alopecia: HyperadrenocorticismDiagnosisHistory, physical examScreening bloodwor

k & UAneutrophils, lymphocytes & eosinophilsCorticosteroidinduced isoenzyme of alkaline phosphataseHypercholesterolemiaLow urine specific gravity Adrenal function testingACTH sti

mulation testDexamethasone suppression testsEndogenous ACTHAbdominal ultrasoundMRI/CT (pituitary & adrenals) Endocrine Alopecia: Sex Hormone Imbalances HyperestrogenismSertoli c

ellOvarian cystsSymmetrical alopeciaVariable pigmentationSeborrheaNipple enlargementDiagnosisEstrogen levelsUltrasonographyTreatmentneuter Endocrine Alopecia: Pituitary DwarfismG

erman shepherd dogs & Karelian bear dogs predisposedAutosomal recessivePersistent cysts of Rathke'spouch compress pituitary gland growth hormone, TSH, may FSH, LH & ACTH Endocrin

e Alopecia: Pituitary DwarfismProportionate dwarfsRetain puppy coat and teeth; over time develop alopecia and secondary infectionsDiagnose with history, examination, radiographs

show persistence of growth plates in bones, CT or MRI to find pituitary cyst, pituitary function testsTreat secondary infections, thyroid supplementation if concurrent hypothyroi

dism Alopecia XVariety of hormonal imbalancesElevated progesterone (common)Low androgensVariable estrogensMild increases in cortisolBreed predispositionsPomeranianChow chowKeesho

ndSamoyedAlaskan MalamuteMales may be predisposed, also seen in femalesCoat changes usually start 1yrsof age Alopecia X: Clinical SignsDull, dry coatLoss of guard hairs (leaving

a "wooly” or puppylike coat)Spares head and extremitiesFrictional areas loose hair firstAlopecic areas become hyperpigmentedHairs do not regrow after clipping Alopecia X: Di

agnosisRule out other endocrinopathies and other causes of generalized alopeciaDocument abnormalities in sex hormonesSkin biopsies Alopecia X: ManagementNeuter intact animalsMela

tonin 36 mg/dog BID for 23 moMelatonin implants “observation”MicroneedlingMethyltestosterone(may cause cholestasis, monitor liver enzymes)Ketoconzole1015 mg/kg BIDop

46;DDD1525 mg/kg daily for 57 days and then twice weeklyTrilostane10 mg/kg daily or 3 mg/kg bid(inhibits 3 hydroxysteroiddehydrogenase) Alopecia X Generalized Alopecia: Dermatoph

ytosis Generalized Alopecia: Demodex Sebaceous AdenitisSee previous discussion Cutaneous T cell Lymphoma Alopecia may be localized, multifocal or generalized; diagnose with biops

y. Paraneoplastic alopeciaAssociated with pancreatic adenocarcinoma and bile duct carcinomasOlder cats Sudden onset of malaise and hair lossMarked exfoliation of hairShiny appear

ance to skin Paraneoplastic AlopeciaDiagnosisRule out other diseases (thyroid and adrenal function tests)Skin biopsies: miniaturization of hair folliclesAbdominal ultrasonography

may find pancreatic or hepatic tumorsManagementNot successful to dateConsider euthanasia Recurrent (Seasonal) Flank Alopecia Canine Recurrent Flank Alopecia Genetic deficiency of

melatonin?Melatonin influences production of other hormones involved in hair growth:ProlactinAndrogensEstrogensGrowth hormone Canine Recurrent Flank Alopecia Diagnosis: r/o othe

r causes of multifocal alopeciaSkin biopsyMarked follicular hyperkeratosis Follicular plugging results in distortion of the hair follicles, keratin plugs extend from primary foll

icles into secondary ones“witches feet” Canine Recurrent Flank AlopeciaManagementObservationMelatonin6 mg q 812 hours Treat approximately 2 monthsDiscontinue when good

hair regrowthMay be used prior to anticipated onset of hair loss to prevent future recurrenceEffective in 5075% of casesMelatonin implant Color Mutant AlopeciaDobermans (blue, so

me red and fawn)Dachshunds (blue)Whippets (blue)Standard Poodles (blue)Great Danes (blue)Chow Chows (blue)Irish Setters (fawn) Color Mutant AlopeciaMelanin clumping in hair bulbs

and shafts results in brittleness (* DIAGNOSTIC CLUE)Hairs breakSecondary infections commonManagement includes use of follicle flushing shampoos (BP, ethyl lactate), antibiotics

for secondary infections, topical emollients and humectants Black hair follicle dysplasiaHair loss and scaling only affects blackhaired regionsSkin biopsies show follicular dysp

lasia with clumping of melanin in hair bulbs and shafts Canine Pattern BaldnessHair loss typically begins around 6 Affected areas includeEar pinnaeVentral neckVentral chest and a

bdomenCaudal thighsPerineal regionAffected breeds includeDachshundBoston terrierChihuahuaWhippetItalian greyhoundGreyhoundBoxerMiniature pinschersManchester terriers Canine Patte

rn BaldnessDiagnosisRule out other causes of symmetric alopeciaBiopsyHair follicles are atrophicResidual hairs have small diameterManagementTry Melatonin ?Observation Congenital

Hypotrichosis Breeds developed to appear hairless, on skin biopsy the hair folliclesare dysplastic and hairs do not reach surface of skin. Feline Symmetrical AlopeciaDifferential

DiagnosesPsychogenic alopeciaAllergies food, flea, environmentalEctoparasitesDermatophytesEndocrinopathiesTelogen /Anagen defluxion Feline Symmetric Alopecia Management Identif

y and treat causeElizabethan collar or sweater trialCorticosteroid trialHormonal therapythyroxineProgesterone (numerous side effects!!!)Antianxiety drugs if suspect psychogenic T

elogenDefluxionStressful circumstance or drug results in all hairs entering telogenWhen new hairs start to grow see a massive shedding of the old hairsCommon example is the postp

artum shedding seen in many breeds of dogs about 6 weeks post whelping Diagnose with history, rule out other causes of alopecia AnagenDefluxionSudden loss of hair within days of

a severe illness or chemotherapyResult of interruption of hair growthHairs are misshapenedDiagnose with history + rule out other causes of alopeciaChemotherapy predisposes to inf

ections and demodicosis From: Secrets in Small Animal Dermatology: page 288 Thank you to Dechrafor Sponsorship!NAVDF provides update Dermatology CE (NAVDF.ORG) 2019 meeting in

Austin, TXWCVD9 in Sydney, Australiaan experience of a lifetime!(October 2024, 2020) Karen L. Campbell, DVM, MSDiplomate, American College of Veterinary Internal MedicineDiploma

te, American College of Veterinary DermatologyUniversity of Missouri Veterinary Health CenterWentzville1092 Wentzville ParkwayWentzville, MO 63385(636) 332(636) 3276400 fax campb