Small Ani. Med- Canine focal-multifocal alopecia (Lecture 2)

wilsbach's version from 2015-11-19 15:52

intro + Bacterial foliculitis

Question Answer
4 common pahogenesises of alopecia?(1) Auto-induced (scratch bc puritic) (2) Sequela of folliculitis (Infectious/non-infectious) (3) Disturbances of the hair growth (Hair cycle abnormalities (telogenization) Follicular dysplasia) (4) Post-scarring
3 common causes of folliculitis which can lead to alopecia?Bacterial folliculitis, Demodicosis, Dermatophytosis
Superficial bacterial folliculitis (PYODERMA)...usually happens why? which agent is the most likely culprit in this problem? (two other possible agents?)Usually secondary to another primary trigger! S. pseudintermediusis the etiologic agent in > 90% of cases; and is considered a OPPORTUNISTIC pathogen. Other possible agents: S. aureus, S. schleiferi.
Staph. pseudintermedius- what problem does this usually cause, where does this bact like to live?culprit of superficial bacteria folliculitis (pyoderma) in most cases. This bact is usually a commensal and is found on most dogs on perineum, perioral skin, nose
Superficial bacterial folliculitis is usually secondary to other problems...what are some of these primary causes which lead to inc colonization? (3 major things and their results)(1) Atopic dermatitis--> Increased adhesion to keratinocytes (Increased colonization) (2) Humidity, seborrhoea, etc.--> Changes in skin ecosystem (inc colonization) (3) Corticosteroid use, hypothyroidism, etc--> Deficiencies in skin immunity (innate, acquired) (inc colonization)
aside from alopecia, which duh this is the alopecia section, what other derm clinical signs might indicate superficial bacterial foliculitis? what is the Distribution like?Multifocal areas of alopecia, follicular papules/ pustules, crusts, scales, collarettes and hyperpigmented macules
what is the distribution of lesions with superficial bacterial folliculitis usually like?All haired skin can be affected, but glabrous regions more commonly affected
is there pruritus with superficial bacterial folliculitis?Pruritus variable, from mild to moderate or severe
If you want to do a cytological exam to try to dx superficial bacterial folliculitis where should you try to get some samples?papules, pustules, epidermal collarettes
how do you usually reach a dx for superficial bacterial folliculitis?(1) History, clinical signs (2) Cytological examination (papules, pustules, epidermal collarettes) (3) Response to antibiotic therapy (4) Biopsy / bacterial culture (these are NOT first line tests)
What are the two topical treatments you can use to tx bacterial folliculitis?(1) Chlorhexidine 2-4% (2) Benzoyl peroxide 2.5% (*can cause dry skin, also warn owners that it might bleach dark fur lighter)
what are the FIRST LINE abx you can use to tx superficial bact folliculitis?Cephalexin, Amoxicillin-clavulanate, Clindamycin
what are the SECOND LINE abx you can use to tx superficial bact folliculitis, and what should you know about moving on to use second line abx?***NEVER START THESE WITHOUT FIRST DOING A CULTURE! Flouroquinolones, Doxycycline, Chloramphenicol, TMS, Rifampin
*what should the duration of tx be like for SUPERFICIAL pyoderma? DEEP pyoderma?Superficial pyoderma– 4-6 weeks. Deep pyoderma– 8-12 weeks


Question Answer
where does demoex usually live?Demodex is a commensal in hair follicles of all dogs (Mites transmitted to nursing puppies by direct contact with mom during the first 2-3 days of life). (Innate immune system controls Demodexpopulations in the skin)
if demodex is a normal commensal of the skin, then when would you consider something "demodicosis"?increased number of mites inside the hair follicles --> folliculitis --> alopecia +/-bacterial infection--> demodicosis
what are the two species of demodex found in dogs? what is the difference between the two?(2) D. canis-commensal in hair follicles of all dogs (2) D. injai- found in sebaceous glands, mostly terriers
which is the demodex that likes to live in the sebaceous glands? esp of terriers?D. injai
how do you differentiate D. canis and D. injai?D. canis has a tail the length of it's body, but D. Injai's tail is MUCH longer
what are the 4 types of presentations of demodecosis?(1) localized (2) generalized (3) Juvenile-onset (4) Adult-onset **can have any combination of these as well
Localized demodecosis- which age group usually gets this type? WHY does this type of demodecosis tend to happen? how would you describe this presentation?Transient and focal overpopulation of Demodex mites. Tends to affect Puppies 3 to 6 months of age (juvenile onset) Because of their Immature immune system.
where, and what are the lesions like for localized demodecosis? (distribution, size, quality of lesions)1 to 4 areas of alopecia with variable erythema, with Lesions no greater than 2.5cm
will you see pruritus with localized democesosis?No pruritus, no systemic signs!!!
which type of demodex affects adults- localized or generalized?generalized can be juv OR adult, localized is only juv (puppies 3-6mo old)
how would you describe the distribution of generalised demodecosis? which age does the generalized form affect?Juvenile or adult-onset! Multifocal or generalized overgrowth of Demodex
is there puritus with generalized demodicosis?Minimal pruritus unless 2o infections also present. +/-Severe skin lesions, +/-Systemic illness (Fever, inappetance, lethargy, Peripheral lymphadenopathy)
Canine Generalized Demodicosis--> why would a JUVENILE onset occur? what ages are considered "juvenile" onset? Is there a breed disposition?Likely a genetic defect leading to a dysfunctional control of Demodex populations. Dogs 3 months to 2 years of age. Many predisposed breeds...American Staffordshire**, sharpei, French bulldog, pit bull, boxer, English bulldog, boxer, Boston terrier, min. pinscher, Jack Russell terrier
Canine Generalized Demodicosis--> why would an ADULT onset occur? what ages are considered "adult" onset? Is there a breed disposition?Dogs older than 2 years. No sex or breed predisposition! This occurs bc the dogs are IMMUNOCOMPROMISED ---> Hyperadrenocorticism, hypothyroidism, diabetes mellitus, neoplasia, immunosupressive drug therapy
*****what is the most common cause of GENERALIZED, ADULT-ONSET demodicosis?Treatment with steroids is the most common cause
does demodicosis have pruritus as a clinical sign?NOOOOOOO-- EXCEPT FOR D. INJAI WHICH DOES!!!!
what are the clinical signs of demodicosis?Multifocal or regional alopecia, Variable erythema, Papules, crusts and comedones, Pustules + collarettes + draining tracts= 2* bacterial infection, Lichenification= chronic, DEMODICOSIS is NON-PRURITIC unless there is a secondary infection present. Also, Systemic signs (anorexia, fever) occasionally seen in advanced cases with secondary infection. You can see lesions anywhere there are hair follicles
what are 2 unusual clinical presentations of canine GENERALIZED demodicosis?(1) Pododemodicosis (Pododermatitisdue to Demodex) (2) Otitis externadue to Demodex
how does Pododemodicosis (Pododermatitisdue to Demodex) present?Erythema, hyperpigmentation, swelling, +/-draining tracts on haired skin. Front paws or all four paws affected
how does otitis externa due to demodicosis present?Bilateral erythematous, ceruminous otitis externa (Mites found on ear cytology)
what kinda skin scrape to dx demodicosis?deep skin scrapings (see RBCs then you know you went deep enough)
how can you dx demodicosis?History, physical examination (multifocal alopecia), Trichoscopy, Deep skin scrapings, Cytology (bact infxns), Occasionally: biopsy and histopathologicexamination
aside from a deep skin scrape, what is another easy dx method to dx demodicosis?Trichoscopy(hair pluck)
So you do a skin scrape and find just one or two demodex. How would you know if it was just the commensal demodex or if it is demodicosis?She said: if scraping a normal animal, shouldn't find demodex. so scrape alopecia animal an find even ONE demodex= demodicosis
where does D. Injai like to live? Which dog? How does this present on the dog?Live in the sebaceous glands, Seen in terrier breeds. You will see: Greasy dorsal stripe of trunk, and also mild to severe prutitus
how do you dx D. Injai infection? How does histopath look? How is it treated?Dx with deep skin scraping (sometimes difficult) or bx. Histopath will show hyperplastic sebaceous glands. Treatment is the same than for D. canisdemodicosis
How do you tx Canine localized demodicosis? (3)(1) Benign neglect (2) Bathing with benzoyl peroxide 2.5% shampoo 1-2x/week (3) Topical antibiotics
what are some of the drugs you can use to tx canine generalized demodicosis?(1) Macrocyclic lactones PO (Ivermectin 0.4-0.6mg / kg daily) (2) Macrocyclic lactones topical (Moxidectin(Advantage Multi® / Advocate®) q weekly) (3) Amitrazdips (0.03-0.05%) weekly (4) Systemic / topical treatment for 2opyoderma
how should you be dosing the ivermectin for tx of generalized demodicosis? *what caution should you know about tx?Ivermectin-start with 0.1 mg/kg/day and increase slowly in 0.1mg/kg increments daily until you reach 0.6mg/kg/day. DO NOT USE IN COLLIES AND COLLIE CROSSES- WHITE FEET NO TREAT If you give it to collies you will see neurologic toxicity (Miosis, lethargy, ataxia, seizure, coma). The problem is a gene, you can do Genetic testing for ABCB1-Δ1 (MDR-1) @ WSU
when should the follow up for tx of generalized demodicosis be? What do you do at the follow up?Monthly follow-up: clinical examination + deep skin scrapings
**when do you maintain tx of generalized demodicosis until?**Maintain therapy until two consecutive negative deep skin scrapings achieved-- Negative skin scraping= zero mites, not dead mites
when treating for generalized demodicosis, what drug(s) should you avoid?glucocorticoids
Occasionally some patients need lifelong treatment of generalized demodicosis...what do you do for tx in this casE?(1) Pulse therapy with ivermectin (need to go up to .6mg/kg ) (2) Advantage Multi q 2 weeks or monthly
If after 4 months of treatment and lesions and/or parasites still persist, consider: (3)(1) Check ivermectinyour dosage! (need to go up to .6mg/kg ) (2) Change to different class of drug (3) Investigate hidden predisposing causes

Dermatophytosis + Summary

Question Answer
what are the three main sp of dermatophytosis involved in canine alopecia?(1) Microsporum canis (zoophilic) (2) M. gypseum (geophilic) (3) Trichophyton mentagrophytes(zoophilic)
how are dermatophytes transmitted?Transmission by direct-indirect contact (contaminated environment)
Who is it more common to see dermatophytes in? (2)(1) Young animals: < 1 year old (2) Yorkshire terriers (and maybe other terriers)
does dermatophytosis cause prutitus?variable, usually low
what is the distribution of the alopeia caused by dermatophytosis?One or multiple alopecic areas on the trunk, head or limbs
what are the 2 possible forms of dermatophytosis?(1) Squamous form: alopecia, erythema, scales, hyperpigmentation (2) Kerion: alopecic, erythematous and exudative, papule or plaque (she said "strange nodules")
wha are the 4 ways to try to dx dermatophytosis?(1) Woods lamp examination (2) Microscopic examination of (fluorescent from woods lamp) hairs (3) Fungal culture (4) bx
what should you know about using a wood's lamp to dx dermatophytosis?First off, it only will fluoresce for M. CANIS but not for M. gypseum or T. mentagrophytes. And THEN, it only fluoresces for 50% of M. canis at that. ALSO you should make sure that the part lit up is tracking along the hairs, because woods lamp can also light up dandruff and stuff as well
what are the 2 mediums used to culture fungi?DTM or plain Sabouraud’s agar
if you are going to bx a dermatophyte infected tissue, what stain will you need to do for histopath?PAS
what are the 3 options you have for topical tx for dermatophytes? how often?weekly/twice a week, clipping if necessary: (1) enilconazole0.2%, clotrimazole (2) lime sulfur 2% to 4% (3) chlorhexidine 3-4%
what are the 4 options you have for systemic tx of dermatophytes?(1) itraconazole (5-10 mg/kg/ 24h; PO with food) (2) fluconazole (10 mg/kg/ 24h; PO with food) (3) ketoconazole (10 mg/kg/ 24h, PO with food) (4) terbinafine(30-40 mg/kg/ 24h; PO)
what ENVIRONMENTAL tx can you do for dermatophytes?bleach diluted 1:10 in water- do daily to weekly
what should you be doing with the affected animal? Housemates?Quarantine affected animal to an easy-to-clean area (so whole household isnt affected), and All in contact animals including carriers without clinical signs have to be identified and treated
how do you know when to stop treating for dermatophyteS?Treatment has to be continued until 3 to 4 weeks beyond 2 consecutive negative follow-up fungal culture results performed q 2-4 weeks
generalized demodicosis VS Dermatophytosis VS Bacterial folliculitis--> number of lesions?generalized demodicosis: VARIABLE. Dermatophytosis: usually <5. Bacterial folliculitis: Many, usually over 10
generalized demodicosis VS Dermatophytosis VS Bacterial folliculitis--> Type of lesions?gen. demodex: Extensive or irregular alopecic and erythematous areas, papules, comedones. Dermatophytes: Alopecia, scaling/crusting, erythema, broken hairs. Bacterial folliculitis: Small alopecic foci, papules, pustules, collarettes.
generalized demodicosis VS Dermatophytosis VS Bacterial folliculitis--> location of lesions?Gen. Demodex: Head, trunk, legs. Dermatophytosis: Head, legs. Bact. Fol: Trunk, abdomen, glabrous skin, head is typically spared

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