Additional Examination Methods In Dermatology

Question 1

What are the basic diagnostic way of dermatology

Answer 1

History –> clinical examination -> additional examinations –> diagnosis

Question 2

What are the most important additional diagnostic methods in dermatology

Answer 2

Skin scraping, biopsy and cytology most imp

- knowing the indication, method, evaluation of result

Question 3

What can we examine in dermatology

Answer 3

 parasites, bacteria, fungi
 hair, skin
 Other organs
(immune-, hormonal system)

Question 4

What methods can we use to examine the skin for the physical exam

Answer 4

inspection / palpation / smelling / percussion

Question 5

Name the additional examinations we can do

Answer 5

• flea comb / Wood-lamp / Otoscopy
• skin scraping + pluged hairshuft sending to laboratory
  (Microscopy, microbiology, sterike swabs, cytology)
• cytology (impression/swab, ear/cytobrush smear, FNA, scraping, biopsy, scotch tape)
• biopsy sampling
• allergy tests
• blood tests
• immunological tests
  –> (histopathology: immunfluorescency, immunhistochemistry)
  (Urine)

Question 6

What additional method would you do in suspicion of fleas

Answer 6

Flea comb and flotation!
Comb, on paper
Flea dirt: digested blood
If few - hard to find, they are fast!
Cat: self cleaning away feces, may not find. If suscpision - treat!

Question 7

What is a woodlamp used for

Answer 7

Nanometer light: ringworm flourescence (not specific, sensitive) but may help to guide you in direction of ringworms!

Question 8

Why are gloves important to use in derma investigations!

Answer 8

Gloves - zoonotic skin diseasaes! Scabies, cayletiella, fungi, ringworm; microspora trichomonas …
Bacteria: staphylococci, pseudomonas - Multiresistant strains! MRSA

Question 9

Why is a camera used during examinations?

Answer 9

Take pictures!
Compairing first with second (control) examination - change, what hasnt changed
Asking help from collegues - owner see everyday - hard to see changes

Question 10

How do we approach sampling and sending samples to a lab?

Answer 10

 Ask: what type of sample is needed for the given examination to not have to do it again if use wrong tube.
 Ordering/ buying of the sampling instruments of the given laboratory (sterile swabs/ tubes with test medium/ solutions for biopsy sampling etc.)
 Accompanying documents and sample labeling to avoid mixing!

Question 11

How do we approach sampling for own examinations

Answer 11

 If we’ got microscope 
– Skin scraping (Paraffin oil on skin surface to get more str corneaum, parasites etc. If send to lab to culture, microbio etc dont do this!!)
– trichogram (eval of hair roots)
– Cytology
 Instruments and materials 
– Scalpel blade, glass slide
– Paraffinoil
– Diff-Quick for staining
– Immersion oil

Question 12

What do we have to remember before performing a sample and evaluating it?

Answer 12

 Appropiate method
– For example: if only superficial skin
scrape was taken - Cannot find demodex - live deep in follicle
- For example: if we are looking for
Sarcoptes mites - Not in lesion - run far away - scrape sample may not find any in scraping
 Correct evaluation of the results
– the possibility of finding Demodex mites is less, we will have only 10-50% possibility of finding them even if we took the sample really from huge region
- Compairing the finding to lesion - eg staph aureus (normal skin flora) but no pyoderma - can negl this result

Question 13

What is the method for skin scraping (for microscopic evaluation and culturing)

Answer 13

We should do all if have no idea of whats going on.
– Superficial (str. Corneum) / deep (Untll first amount of blood is seen - small erosion is made)
pushing out of hair follicle / pulling out hair shufts (trichogram) (If see anything filling the follicles
Also pull out hair shaft on border of healthy and skin lesion part - most fresh, most infected part)
– Huge surface / many region / border of the lesion and healthy skin (Sarcopes - fast)
– Crusts are not needed but sampling from the str. corneum (feline demodex(other demodex live in hair follicles), Ringworm - dermatophytosis
Can live on str. Corneum or they can live on hair shaft
–> need sample from both! Take sample beneath crust formation in str corneum!!!!

Question 14

How do we evaluate the skin scraping (for microscopic evaluation and culturing)

Answer 14

– Sensitive method for ectoparasites, except Sarcoptes mites
– Bacterial culture: the antibiotic resistance is important
– Fungal culture: the only sure method for proving Dermatophytosis (Scrape + culture is the basis of diagnosis of ringworm! (PCR yes, suscpicion woodlamp no diagnosis)

Question 15

What are the basic materials for own and lab sampling

Answer 15

Lab - swab etc. sample in sterile syringe

Own exam: slide, paraffin oil

Question 16

For what infectious causes do we need multiple supf scrapings?

Answer 16

• (mange)Sarcoptes scabiei (var. canis, ear pinnae cat)
• (mange)=Notoedres cati (ususally found on cats ear pinnae first)
• (mites)Otodectes cynotis (ear mite, cat)
  These we def find if correct sampling:
• Linognathus setosus; Cheyletiella yasguri; Neotrombicula
• sucking louse (pediculosis);cheyletiellosis; trombiculosi
• ringworm/dermatophycosis: Gold standard scrape + micr culturing. Hair shaft cuticle no longer intact!!

Question 17

As we should take skin scraping for sarcoptes from a huge area - what areas are the most important to do?

Answer 17

• Multiple supf scrapings - Predlection sites: thin skin (ear pinnae, hock, elbow, Ventral
• Overgrowth - will probably find
  May only find eggs - also good for diagnosis

Question 18

What is typical for dermatophycosis signs?

Answer 18

Patchy alopecia, caryion/inflammation,

Question 19

Multiple deep scrapings - when, how

Answer 19

Demodicosis!
Until first capillary bleeding - demodex -> onto slide
Sharpei - thick skin - may not be able to do this sample! Biopsy may be needed
Microscopy - found on/around hair shaft/root/follicle!
(Face, back, btw toes, neck ventral/dorsal)

Question 20

When do we use swabs

Answer 20

In case of pus

Question 21

Trichocram - how do we sample for it, what are we looking for?

Answer 21

Hair sampling - looks like just cut some hairs off, tape on skin, (demod. Probably with root imp too)
 Demodicosis: on shaft (follicle)
 Dermatophytosis/ringworm: we see the hair shaft is no longer intact
 Cheyletiella: eggs are found on the hair shaft.

Question 22

Trichogram - how can we differentiate alopecia?

Answer 22

• primary vs secundary(licking etc) alopecia - easily pullable shaft indicates primary. Symmetric alopecia abdomen cat, no skin lesion indicates no licking.
• Distal end trauma indicates pruritis. (Distal end - should be sharp, if self trauma - pruritis. CAT!! Owner may not be able to see if incr self groowning, done at nigh.)
• Radix: thick radix of shaft - anagen/growth phase. 2´Alopecia due to pruritis - it grows back!
• Telogen phase: thin, primary alopecia (hormonal, aquired foll. Dysplasia) Spontanious loss. (Sligtly widened end, resting phase of hair growth - fall out)

Question 23

Method of cytology

Answer 23

• impression-smear (glass-slide; scotch tape) Sensitive: malessia, staph, bact pyoderma (staph)
• aspiration (FNA) Nodule: inflamm vs neopl or both
• swab smear (from extarnal ear canal) Any pus, fluidy.. do a smear!!
• ”cytobrush” (PCR: papilloma/herpes etc.)
  (- from skin scraping or biopsy sample)

Question 24

Evaluation of dermatological cytology

Answer 24

– Sensitive method: bacterial and Malassezia owergrowth (easy to spot if present)
– (FNA?) Differentiation of inflammatory (septic / non septic) and neoplastic skin lesions:
– Fast, but not always giving exact final diagnosis

Question 25

Describe the different smear methods

Answer 25

 Direct smear (placing sample direcly on slide with eg a pipette; blood, or placing feces on slide and adding saline)  Impression smear (placing slide directly on surface to be sampled)  Swab smear (rolling swab with sample on slide)

Question 26

Cytology - FNA

Answer 26

Aka fine needle biopsy - Make vacuum inside nodule – needle in center, until we see something aspirating - When pulling out the needle no NOT have vacuum! Contamination with skin cells.. - Big needle used - Take off needle, aspirate a bit, put needle back on, and blow it on slide. If too thick – smear

Question 27

How can you stain a scotch tape slide sample?

Answer 27

Same as with normal slide! (Diff quick)

Question 28

Diagnostic value of HP - which skin diseases need HP for their diagnosis?

Answer 28

(Biopsy) - skin tumors - inherited/congenital diseases - autoimmune dermatopathies - aquired alopecia - follicular dysplasia - keratoseborrhoeatic skin diseases - any case where we dont know whats going on - do biopsy!

Question 29

Diagnostic value of HP - which skin diseases DOESNT need HP for their diagnosis?

Answer 29

- Ectoparasitosis - pyoderma - supf. Mycosis - allergodermatitis (typically food allergy!) - endocrinodermatopathies (eg. Thyroxine suppr/stim)

Question 30

Cytology - how can you differentiate deep from sterile pyoderma

Answer 30

- Bacteria present in deep pyoderma - p. Aeruginosa, or staph spp. Which is most common, intermedius!) - in sterile pyoderma you wont see any infectious casue, and rather a bunch of NG..

Question 31

How can you recognize Malassezia pachydermatis in cytology

Answer 31

A yeast, they make "foot step" lesions in microscope. Greasy skin surface typical, Rancid Impression smear is made.

Question 32

Cytobrush

Answer 32

Collection of cells used for cytology and PCR | Spoolie

Question 33

Biopsy

Answer 33

- local anasthesia at site - Scalpel – at border of healthy-disease area (we cut) - Biopsy punch – do only at disease area!! Cant be sure the horisontal incision is taken only from healthy if 50:50 like with scalpel - Min. 3 biopsy from each lesion + 1 from healthy region - Cut (twist) punch in one direction only - after: o May get stuck in punch – pull out with needle -> put in formalin o Cut end with scissors o Suture with 1-2 suture (dep on the diameter tho) o Disinfect with betadine, aluminium spray o Can also push the biopsy onto slide then stain – not so informative

Question 34

Intradermal skin test, metadodic allergy test

Answer 34

- ONLY after excluding all other diseases, esp sarcoptes. - A lot of false positives.. wrongly give steroids – may cause huge problem!! - we inject different allergens in skin to check for allergic reactions (inflamm, red, hevelse..)

Question 35

Blood sampling in dermatology - what can it detect?

Answer 35

- allergies - serology - Sarcoptes: IgG-serology - Blood count, biochemistry, hormones (endocrinobathies..)

Question 36

Demodex mite occurance

Answer 36

- demodectic mange - all mammals have them! Transmission from mother at birth. - Immunosuppr -> clinical lesion (overgrowth) - Indicator disease (indicates immunosuppr.) - Pyoderma – always look for them (=heavy immunosuppression!) - common in dog, less common in cat

Question 37

Diagnosis of pyoderma

Answer 37

Must check microscopy aswell to confirm – NG, babcteria. (Lines are seen, strands on slide – dna pushed out from NG! Pushed too hard during sampling)