Atopic dermatitis treatment

Question 1

How is atopic dermatitis diagnosed?

Answer 1

By exclusion:
you rule out ectoparasites(sarcoptosis,
otodectosis, pediculosis, cheyletiellosis,
trombiculiasis, demodicosis),

treat all possible secondary infectons (Staphylococcus
pseudintermedius ja Malassezia spp),

then you rule out food allergy,

and then, if everything else has been ruled out - you can call it atopic dermatitis.

Consider Clinical signs and history. Favrot. Allergy testing.

Question 2

Name allergic skin diseases. (5)

Answer 2

atopic dermatitis
food allergy
flea allergy
mosquito bite allergy
contact dermatitis

Question 3

What is atopic dermatitis? (3)

Answer 3

Atopic dermatitis is genetically predisposed
inflammatory skin disease - interplay
between allergen sensitization, microbial
dysbiosis and skin barrier abnormalities.

Question 4

What is allergy? (4)

Answer 4

Allergy is HYPERsensitivity.

In case of atopic dermatitis,
* there are IgE antibodies
* Epidermal barrier defects
* Sometimes secondary infections

If you find the IgE antibodies, its called atopic dermatitis, but if you can’t find them then its called atopic-like dermatitis.

Question 5

When is it called atopic dermatitis and when is it called atopic-like dermatitis?

Answer 5

If you find the IgE antibodies its called atopic dermatitis, but if you can’t find them then its called atopic-like dermatitis.

Question 6

Typical areas of the body affected by atopic dermatitis?

Answer 6

lips
periocular
ears (pinnae and canal)
antecubital fossa
paws
axillas
groin
perianal area

Other areas possible too.

Question 7

Pediculosis in animals.

Answer 7

Pediculosis in animals refers to an infestation of lice leading to symptoms such as itching, hair loss, skin irritation, anemia (in severe cases), and reduced productivity in farm animals.

Lice are species-specific, meaning they typically do not transfer between different animal species or to humans.

Infestations are more common in conditions of overcrowding, poor hygiene, and cold weather when animals have thicker coats.

Treatment involves topical insecticides, medicated shampoos, or systemic treatments such as oral or injectable antiparasitics, alongside improved sanitation and management practices to prevent reinfestation.

Question 8

Cheyletiellosis, also known as

Answer 8

“walking dandruff,” is a contagious skin disease in animals caused by Cheyletiella mites.

These mites primarily infest dogs, cats, and rabbits, living on the surface of the skin and feeding on keratin and tissue fluids.

The condition is characterized by excessive scaling, itching, hair loss, and skin irritation, with the mites appearing as moving dandruff flakes.

Cheyletiellosis is zoonotic, meaning it can temporarily affect humans, causing itchy, red bumps.

Question 9

Explain Favrot criteria.

Answer 9

The Favrot criteria are a set of diagnostic guidelines used to help identify canine atopic dermatitis (CAD). You need 6 or more to diagnose atopic dermatitis.

1. age of onset under 3 y
2. mostly indoor
3. corticosteroid responsive pruritus
4. chronic or recurrent yeast infections
5. affected front feet
6. affected ear pinnae
7. non-affected ear margins
8. non-affected dorso-lumbar area

Sensitivity (58.2%): If a dog truly has canine atopic dermatitis (CAD), there is a 58.2% chance that the Favrot criteria will correctly identify it as positive. This means some cases may be missed (false negatives).

Specificity (88.5%): If a dog does not have CAD, there is an 88.5% chance the criteria will correctly identify it as negative. This means fewer false positives, making it a good rule-in test.

These criteria are not definitive but serve as a useful clinical tool.

Question 10

Pruritus scoring:

Answer 10

visual-analog scale

10 = extremely itchy, needs to be restrained to keep from scratching

2 = very mild, occasional itching

Question 11

What is the pruritus threshold?

Answer 11

Different factors that contribute to the pruritus meaning if you have e.g. mild allergy you may not see signs but with stronger allergy, you’ll get signs.

Or a mild allergy that wouldn’t be pruritic on its own is combined with fleas which cause the pruritic threshold to be crossed.

That’s the idea with all atopic animals always being treated with antiparasitics.

So take care of these from the get-go:
1. Parasites
2. Dry skin
3. Secondary infections

Question 12

Treatment phases can be either

Answer 12

Long term treatment which is proactive treatment to keep the allergy under control.

or

Treatment of acute flares (allergens, parasites,
infections, dry skin).

Tx is always tailored individually!
Atopic dermatitis is for life!

Question 13

4 main options/points for atopic dermatitis tx

Answer 13

1) Allergen avoidance (if possible)

2) Allergen specific immunotherapy - ASIT (is lifelong regular injections)

3) Barrier function enchancement (lipids, ceramides, omega 3, supplemental oils, derm food etc.)

4) Anti-inflammatory treatment (most important)

Question 14

Allergen avoidance can involve (2)

Answer 14

• Environmental allergy testing and avoidance
• Flea treatment

Ectoparasite control should be continuous, not intermittent.

Question 15

Why do we favor edible isoxazolines vs spot-on tx in allergic dogs?

Answer 15

Allergic dogs may need frequent washing so oral isoxazolines are a better option in these cases.

Afoxolaner – Found in NexGard (for dogs)

Fluralaner – Found in Bravecto (for dogs and cats)

Lotilaner – Found in Credelio (for dogs and cats)

Sarolaner – Found in Simparica (for dogs)

Selamectin + Sarolaner – Found in Revolution Plus (for cats)

Question 16

Allergens can be tested for by (2)

Answer 16

1. Skin test
2. Serum test for antibodies

Question 17

Describe ASIT pros and cons.

Answer 17

Allergen specific immunotherapy (ASIT) requires a skin or serum test first in order to identify allergens from which to make the therapy-drug product.

More efficient in younger animals, who don’t have chronic skin changes. Is Something you can try in every atopic animal (dog) if the owner is motivated.

Usually a once monthly inj. (dogs/cats), sublingual also available for dogs but not for cats.

Pros:
- Is cheap for large dogs. One bottle lasts like 9 months.
- Might relieve all symptoms.

Cons:
- can be used only in case of positive
allergy testing
- takes time for onset of effect, might start to work in 12 months - other treatments needed while you wait.
- helps about 60-75% of dogs
- usually needs life long therapy if it works

Question 18

Describe Enhancing epidermal barrier.

Answer 18

Weekly shampooing (skin friendly shampoos or chlorhexadine for secondary infections (e.g. douxo pyo), conditioner use also possible), purpose: cleaning, rehydrating, allergen removal.

Give Essential fatty acids by mouth or topically:

• Allerderm spot-on® (Allerderm is a unique blend of cerumides and fatty acids which helps to restore the skin’s natural defences.)
• Dermoscent spot-on ® (contains various oils)
• Retopix spot on ® (contains Adelmidrol, an aliamide able to normalize the function of cutaneous mast cells (degranulation))

Question 19

Anti-inflammatory drugs are the most important tx for pruritus. Name 6 options.

Answer 19

1) Topical corticosteroids
2) Systemic corticosteroids (broadest effect)
3) Systemic cyclosporine
4) Systemic oclacitinib (Apoquel)
5) Lokivetmab injections (Cytopoint) (narrow effect, only against 1 cytokine)
6) (Antihistamines) (in parantheses because they aren’t that effective for pruritus compared to the other options / only work against histamines)

NB systemic corticosteroids also inhibit/decrease cerumen production!

Question 20

anti-inflammatory vs anti-itch drugs, give examples

Answer 20

corticosteroids/cyclosporine are anti inflammatory

oclacitinib is both

lokivetmab/antihistamines are anti itch

Question 21

Describe topical corticosteroids pros and cons.

Answer 21

Pros:
+ cheap, safe
+ suitable if few body parts affected
+ very good for interdigital space, ears!
+ reduces lichenification

Cons:
- can’t use if hairy dog or many body parts need treating
- can cause skin atrophy

e.g. Cortavance spray (hydrocortisone)

NB don’t use excessive topical steroids in cats cause their skin is so much thinner, the sprays aren’t licensed for cats and they may lick the product up. You can use them in some special cases, e.g. acute flare, in the ears etc.

Question 22

Answer 22

skin atrophy in a dog

in other cases, you can see blood vessels through the skin, it gets very dry etc.

steroids inhibit collgen and elastin etc.

Question 23

Pros and cons of Systemic corticosteroids.

Answer 23

Pros:
+ Cheap, effective, fast acting, good for edema,
stenosis of ears, chronic inflammation, fights
inflammation very well

Cons:
- Side effects (all corticosteroid side effects like adrenal suppression, PU/PD, polyphagia, + watch out for calcinosis cutis, demodicosis etc.)

NB cats with latent herpes can develop coughing and sneezing etc. on steroids as the herpes reactivates.

Question 24

Answer 24

Demodicosis due to immunosuppression due to steroid use.

Question 25

Answer 25

Calcinosis cutis + pyoderma due to overuse of steroids.

Question 26

Answer 26

Calcinosis cutis, on fna you'd get a granular texture from the plaques/thickened skin. ## Footnote DMSO (industrial solvent) can technically dissolve calcinosis cutis but is not available in some countries. You would apply it topically, it absorbs through the skin.

Question 27

What is the mechanism behind why steroid use induces calcinosis cutis? How do steroids affect calcium homeostasis in animals?

Answer 27

Steroids cause dermal atrophy by breaking down proteins and collagen in the skin which exposes negatively charged phospholipids that attract calcium ions, leading to calcium salt deposition. Chronic steroid use can lead to increased serum calcium and tissue mineralization. Steroids impair fibroblast function and slow wound healing, making skin more susceptible to dystrophic calcification. Glucocorticoids can increase skin pH, which promotes calcium phosphate precipitation. Steroids inhibit vitamin D activation, reducing calcium absorption from the gut. They promote urinary calcium loss, potentially leading to hypocalcemia. Chronic steroid use increases osteoclast activity, leading to bone demineralization and calcium release into the bloodstream.

Question 28

Describe Corticosteroid use, dose, frequency. (3)

Answer 28

* Prednisolone (for dogs), methylprednisolone (for humans and cats) * 0,5 mg/kg once or twice daily or even EOD (every other day) * For control: blood test, urine sample ever 6-12 months (avoid iatrogenic cushings and diabetes)

Question 29

Pros and cons for Systemic cyclosporine.

Answer 29

+ good for pruritus + inflammation, is as effective as steroids Cons: - takes 3-4 weeks before you see effect - nausea, vomiting in the beginning of treatment - hypertrichosis, gingival hyperplasia - cost NB cats may develop toxoplasmosis when on cyclosporine so test the cat first, you want them to have antibodies. If the cat does not have toxo titers, they would get immunosuppressed on cyclo and then maybe catch toxo outside and it could kill them. ## Footnote 5 mg/kg dog, 7 mg/kg cats with a smaller start that is slowly increased in order to avoid side effects and given with food.

Question 30

Name two cyclosporine products. Describe their use.

Answer 30

cyclavance (liquid), atopica (pill) * Immunomodulator * 5mg/kg daily in the evening * Half the dose if effective * Start with full stomach, in the evening, later give on empty stomach when animal acclimatized. * you can increase the dose slowly to reduce side effects in the beginning. * blood test once a year ## Footnote Optimmune is an example of a topical cyclosporine product.

Question 31

Pros and cons of Oclacitinib. How does it work?

Answer 31

Works through interleukin modulation. Pros: + fast acting + very few side effects Cons: - side effects: diarrhea, papillomatosis - cost - not effective in every dog - doesnt always work for full 24 hours so consider BID adminn. instead of SID - check blood test regularly (once a year) | Might work in cats but is off label so use caution. ## Footnote Apoquel: Start with double dose and then reduce to maintenance dose so 0,4-0,6mg/kg twice a day for 2 weeks, after that 0,4-0.6mg/kg once daily.

Question 32

Pros and cons of Lokivetmab (Cytopoint).

Answer 32

Works against a specific interleukin. You need at least 2 inj. to gauge whether it will work in an individual animal. Works in approx. 75% of dogs. Pros: + fast acting + easy for the owner (no pills given at home) injection once a month/up to 12 weeks. + great for pruritus + few side effects, if any Cons: - cost (130+ euros 40kg) - doesn’t work in every dog - veterinary visits needed monthly

Question 33

Pros and cons of Antihistamines toward pruritus.

Answer 33

Cons: - works in only about 10% of dogs Pros: + may help to reduce corticosteroid dosage needed to reduce pruritus if used together + a few side effects (sleepiness) Cetirizin 0,5-1mg/kg Loratadine 0,5mg/kg

Question 34

When Flare ups occur, do what?

Answer 34

* Confirm no Infections, parasites, new allergens. * Do Cytology always. * Topical steroids, systemic corticosteroids good for acute flare ups; maybe consider oclacitinib, lokivetmab if there isn't too much inflammation.

Question 35

Treatment for skin infections. (5)

Answer 35

1) Antiseptics such as chlorhexidine 3-4% works against yeast and bacteria 2) Topical antibiotics/antifungals 3) Systemic antifungal 4) Systemic antibacterial in certain cases. 5) Epidermal barrier enhancement (Pyospot, fatty acids, Atop7 spot-on, Allerderm etc.)

Question 36

Treatment options for cat allergies. (6)

Answer 36

1) Topical steroids (NB skin is thin!) 2) Systemic corticosteroids (higher doses than in dogs; prednisolone 2mg/kg q24h) Long acting steroids? 3) Cyclosporine (higher dose 7mg/kg q24h). Consider testing for toxoplasmosis, FIV. 4) Antihistamines (cetirizine, higher dose 1mg/kg 24h) 5) Immunotherapy injections 6) Oclacitinib? Off label, higher doses, is it safe? Questionable. | Prednisolone is the first-line drug choice in cats. ## Footnote Fatty acids either orally or spot-on.

Question 37

Flea allergy dermatitis tx.

Answer 37

Simply persistant flea therapy for the patient and other in-contact animals all year around. Treatment of the environment too (Indorex). It may take months to resolve