Clin Med - Derm 1

drraythe's version from 2016-03-15 00:39


Question Answer
**What is a 1° lesion?Initial eruption that occurs due to an underlying dz which occurs spontaneously
**What is a 2° lesion?Lesions which evolve from a 1° lesion or are czd by some exogenous factor such as the PTx or medications
What is a Macule? 1° or 2° lesion?Non-raised, circumscribed, area of discoloration that is up to 1cm in diameter. 1° lesion
What is a Patch?Similar to macule (non-raised, circumscribed, area of discoloration), but larger than 1 cm. 1° lesion
What is a Papule?Solid erythematous (red) elevation in the skin up to 1 cm in diameter. 1° lesion
What is a Plaque?Flat-topped elevation in the skin, larger than a papule (papule is up to 1cm, so plaque is >1cm). 1° lesion
What is a Nodule?Small, circumscribed elevation >1cm in diameter that extends into dermis or below. 1° lesion
What is a Tumor?Mass of varying size that can involve any layer of the skin and/or subcutaneous tissue. 1° lesion
What is a Pustule?Small, circumscribed elevation w/in epidermis filled w/ purulent exudate; often preceded by a papule. 1° lesion
What is an AbscessAccumulation of purulent exudate w/in dermis or subcutaneous tissue; lesion often fluctuant, but can be firm. 1° lesion
What is a Vesicle?Elevation of the epidermis filled w/ clear fluid that is up to 1 cm in diameter. 1° lesion
What is a Bulla?Vesicle(elevation of the epidermis filled w/ clear fluid) larger than 1 cm in diameter. 1° lesion
What is a Cyst?Cavity filled w/ either fluid or semi-solid material, lined by epithelium. 1° lesion
What is a Wheal?Circumscribed, edematous raised lesion. 1° lesion
What is a Epidermal Collaret? 1° or 2° lesion?Circular ridge of scale that represents the remnants of a pustule, papule, vesicle or bulla that has regressed. 2° lesion
What is a Scar? 1° or 2° lesion?Area of fibrous tissue at site of previous trauma or lesion; often alopecic & depigmented. 2° lesion
What is a Erosion? 1° or 2° lesion?Superficial lesion w/in epidermis that does not penetrate into the dermis. 2° lesion
What is a Ulcer? 1° or 2° lesion?Deep lesion through epidermis extending into dermis. 2° lesion
What is a Fissure? 1° or 2° lesion?Linear lesion (crack) into or through epidermis. 2° lesion
What is Excoriation? 1° or 2° lesion?Self-inflicted lesion (scratching, biting, rubbing) causing removal of epidermis. 2° lesion
What is Lichenification? 1° or 2° lesion?Thickening & hardening of the skin causing exaggerated skin markings; associated w/ chronic inflammation or trauma. 2° lesion
What is Hyperkeratosis? 1° or 2° lesion?Thickened horny layer of epidermis; ie. callus. 2° lesion
What is a Scale? 1° or 2° lesion?Accumulation of cornified cells; can vary in consistency, color & size. Could be 1° or 2°.
What is a Crust? 1° or 2° lesion?Composed of dried exudate, blood, serum, scales. Could be 1° or 2°
What is Alopecia? 1° or 2° lesion?Hair loss. Could be 1° or 2°
What is a Comedo? 1° or 2° lesion?Dilated hair follicle filled w/ cells & sebaceous secretions. Could be 1° or 2°
What is Hyperpigmentation? 1° or 2° lesion?Due to ↑ melanin w/in epidermis +/-dermis. Could be 1° or 2°
What is Hypopigmentation? 1° or 2° lesion?Loss of epidermal melanin. Could be 1° or 2°
**Which direction should skin scrapings be done in, relative to hair?Skin scrapes should always be performed in the direction of the hair growth
**Which direction should skin scrapings be done in, relative to yourself?Skin scrapes are best performed when the scrape is performed in the direction towards yourself (not away from you)

Intro to Derm

Question Answer
DAMNIT-V acronym - D?Degenerative, Developmental
DAMNIT-V acronym - A?Anomalous, Allergic, Autoimmune
DAMNIT-V acronym - M?Metabolic
DAMNIT-V acronym - N?Neoplastic, Nutritional
DAMNIT-V acronym - I?Infectious (bacterial, fungal, viral, parasitic), Inflammatory, Immunemediated, Idiopathic, Iatrogenic
DAMNIT-V acronym - T?Trauma, Toxic
DAMNIT-V acronym - V?Vascular
What are the 3 layers of the skin? Where is adipose located? Where is dense irregular CT located? Where are dermal papillae located?Epidermis
Adipose is in the hypodermis
CT is in the dermis & the dermal papillae are small, nipple-like extensions (or interdigitations) of the dermis into the epidermis
1⁰ dermatological lesions can be due to what 3 things?Idiopathic
Endocrine dz
(directly associated w/ whatever dz is goin on)
2⁰ dermatological lesions can be due to what 2 things?Exogenous factors, Self-inflicted (excoriation)
*What 4 1⁰ (or *1⁰ & 2⁰) lesions are related to color changes?Macule
What is Diascopy, what is it used for & how to you perform it?Diascopy is a way to determine if a reddened area is a macule (local inflammation) or ecchymosis/petechia (bleeding problems). You take a glass side & you press it against the lesion. If it blanches, it is bc they BVs are just engorged from inflammation & you were able to push the blood out. If it doesnt blanch, it's bc the blood is extravascular, which indicates a bleeding disorder. So diascopy is a test of BLANCHABILILTY
In short words, difference btwn 1° & 2° lesions?1° is bc of a dz
2° is bc of an exogenous factor (tme, sun, etc) or it's self-inflicted
What are 4 raised lesions?Papule
W/ 1° lesions, thinkColor change
Coalescing papules form?A flat-topped plaque
Vesicles/Bulla are often associated w/ what kinda dz? (Not a virus)Autoimmune
Who can ulcers be a 1° lesion on & what is this called?Shetland sheep dogs, it's called ulcerative dermatosis
What are 2 things that papules can be associated w/?Can be associated w/ mites-demodex & sarcoptes
What are some things that a nodule can contain?Inflammatory cells &Neoplastic cells. Some sort of infiltrate, either inflammatory or neoplastic
What does a wheal indicate?It is a 1° manifestation of an allergic rxn
What are 4 fluctuant lesions?Pustule
Papule → ____ → ____ what is this progression?Papule → Pustule → Epidermal collaret
What are pustules full of?PURULENT EXUDATE!!! NOT PUSS - bc otherwise you have to describe it as "pussy" lol
Who do you see vesicles/bullae more often in & why?More common in LARGE animals, bc they have thicker skin-in small animals, it forms & usually pops right away
What is the difference btwn an Erosion & an Ulcer?An ulcer is when the lesion is through the epidermis & starting into the dermis
If you see Lichenification, what are you thinking?CHRONIC conditions
If you see a Epidermic Collaret, what do you think it came from?Probably either a pustule or a vesicle was here
What are 3 dzs which might cz there to be Comedos?Demodex
1° Schnauzer Comedo Syndrome
Crusts (scabs) might be 1° to what & 2° to what?1° - Zinc responsive dermatosis (zinc deficient or unable to mobilize it, 1° lesions are crusts)
2° - Pustular dz
What does AD, AS & AU stand for?AD - Rt ear
AS - Lt ear
AU - Both ears
How can Hyperpigmentation be 1°? 2°?1° = Hyperadrenocorticism
2° = Chronic inflammation
How can Hypopigmentation be 1°? 2°?1° = Genetic
2° = Acute inflammation
Hyper vs Hypo-pigmentation. Which is a result of chronic & which is a result of acute inflammation?Hyper = Chronic
Hypo = Acute
Alopecia can be associated 1° w/, 2° w/?1° = Cushing’s
2° = Pruritus
What are the 2 kinds of Seborrhea?Seborrhea sica (dry) & Seborrhea oliosa (oily)
What is the false neg rate of Demodex on skin scrapes?0%!!!! As long as you did the scrape right. The exception is sharpeis tho
What is the false neg rate for Sarcoptes on skin scrapes?50%!!!! Hard to see on a skin scrape (if you see them, can ID bc they have really stubby legs)
What does OD, OS, OU stand for?OD - Rt eye
OS - Lt eye
OU - Both eyes
When describing a lesion, what 2 big things must you keep in mind?The LOCATION (diffuse/generalized? multifocal? focal?) & the SEVERITY(mild, moderate, severe)
Demodex vs sarcoptes → which is a superficial skin scraping for dx, which is a deep?Superficial Sarcoptes
Deep Demodex
How do you know you've properly gone deep enough for a deep skin scrape?You will see capillary bleeding
5 methods for hunting for parasitesSkin scraping (deep or superficial)
Coat brushing
Trichogram (hair pluck)
Tape test
Cotton swab w/ oil
When would you wanna use a deep or superficial skin scrape?MITES! Demodex or scabies
What is a trichogram & what would you wanna use it for?Aka hair pluck, you can use this to dx Ringworm (fungal infxn), or find lice eggs which are usually cemented onto hairs. You can find Demodex attached to hair follicles (rarely find mites on pluck or scrape if healthy animal)
Why might you want to use a tape test?Might find cheyletiella or a nymph or a tick or something
When would you use a cotton swab w/ oil as a diagnostic tool?Put in ear, roll into microscope slide & look for otodectes (ear mites)
If you have done skin scrapes, but can't find demodex & you SWEAR it's demodex (or it's a sharpei), what can you do?Skin biopsy (however, false neg rate w/ a proper skin scrap is SUPER LOW-should be able to get them)
Look at slide 17 for "name that bug" exerciseGood to know
*Be sure to look over example cases/picturesHelpful
If pawpads are involved, what might you think?Autoimmune
Whats the little mite that likes the feet?Demodex
How would a yeast infxn of anywhere usually present?Brown/waxy substance w/ no draining tracts (this appearance would lead you towards yeast more than bacteria)
Why can you only use purple stain for impression smears w/ dogs, but you want the red dye too w/ cats?Bc cats have lots of problems concerning EOSINOPHILS, which need the red dye to show up
What are 3 methods you can use for diagnosing microscopic problems?Impression smear, cotton swab, tape test
If you are doing a tape test, what should you avoid using while you process the tape to look at it?Avoid the fixative step of the stain - it contains alcohol which ruins the tape's adhesive side
If you think you are going to be looking at yeast, what part of the processing should you avoid?The fixative, which contains alcohol
look at "name that microbe" on slide 20Helpful
What is the type of Staph which animals get?Staph pseudintermedius (NOT aureus, that more for ppl)
Which 2 diagnostic methods can you use for looking at cytology?Tape test & impression smear
If you see a bunch of eosinophils, who did this prolly come from?A cat
Acantholytic keratinocytes - when do you usually see these?Usually find in Pemphigus Folaceaous (autoimmune to desmosomes)
How would you describe Ringworm?Multifocal alopecia w/ severe/complete alopecia at each lesion, moving outward over time
What are the 3 Ddx for patchy Alopecia?Dermatophytosis (ringworm)
Superficial pyoderma
If you are trying to get a culture of a dermatophyte, where do you scrape?At the EDGE of the lesion, NOT the center!! the edge is where the active infxn is
What are the 2 fungal culture mediums?DTM (Dermatophyte Test Medium) & Sabaroud’s agar
What are the 3 major dermatophytes we will be looking at?Trichophyton mentagrophytes
Microsporum canis
Microsporum gypseum
Look at slide 23 for pics of the dermatophytesWoohooo
How can you tell the difference btwn Microsporum canis & Microsporum gypseumGypsum will have less than 6 cells in its structure, canis will have greater than 6 & have thicker walls, as well as have a terminal bud (Canis (dogs) are THICK skinned & can take more than 6 hits, that's why they're our BUDS)
Strands of fungi are called?Hyphae
Trichophyton mentagrophytes → what does this look like to identify it?Thin walled & rounded ends w/ more microconidia than macroconidia (more tiny crap)
What does a TVT cell look like?Round cell w/vaculoles
1 way you know you're looking at an Acantholytic Keratinocyte?(d.iii.2) Normal keratinocytes lose nucleus as moves up through the diff keratin cell layers as it develops - These cells have separated too early - still have nucleus (while all the cells around it dont)