5. Atopy, Flea allergy, Food sensitivity Flashcards
What does atopy mean?
An exaggerated production of IgE immune response against otherwise harmless substance in the environment
What is atopic dermatitis?
A genetically determined chronic pruritus dermatitis
What is atopic dermatitis sensitive / have a predisposition for?
Developing an immediate type I hypersensitivty to specific allergens
What is one of the most common causes for development of chronic recurring inflammatory skin disease?
Atopic dermatitis:
Involving complex interactions of
- environmental
- genetic
- microbial
- immunological
- pharmacological factors
What are the general age predisposition in atopic dermatitis?
Between 6months - 3 years
BUT there is a great variability so should not be ruled cause of age.
Mention a few breeds which are predisposed for atopic dermatitis
Golden-, Labrador retriever, Beagle, Dalmatian, Cocker Spaniels. French Bulldogs
What are 3 typical signs of atopy?
- Atopic dermatitis - one of most typical signs. Other two sometimes occur and not always together
- Atopic rhinitis
- Atopic conjunctivits
What are the forms of atopic dermatitis and what do they mean?
External form - Production of IgE
Internal form - Without production of IgE
Name a few intrinsic factors that can influence onset of dermatitis
- Genetical predisposition
- Immune response
- Specific features of skin barrier hydrolipid barrier which pathogens can have an affinity for.
Name a few extrinsic factors that can influence onset of dermatitis
- Mites
- Mold spores
- Pollens
- Epithelial cells of different species that can act as a provoking allergen: Food allergens is seen in about 30% of atopic dogs and Pseudointermedius or Malassezia spp.
What are clinical signs of atopic dermatitis and where on the body are the distributed?
Most commonly presented as
- pruritus
- erythema
- secondary microbial infections (Staphy. or Malassezia pachydermatis frequent findings in atopic dermatitis)
- papules (very small 1mm)
- Otitis externa (seen in 4/5 cases)
Pruritus and lesions typically involve:
- face
- around eyes
- lateral ear plot (concave ear)
- ventral abdomen
- perianal regions
- interdigital areas
- Lateral symmetry is common.
What are clinical signs of atopic dermatitis in CATS?
- Facial or ear pruritus
- Miliary dermatitis
- Eosinophilic granuloma complex (granuloma, ulcer plaque)
- Symmetrical alopecia
- Generalized pruritus
How many criterias should be fulfilled for diagnosis of atopic dermatitis?
5 to confirm atopic dermatitis
How can we diagnose atopic dermatitis?
NR 1 - According to history
But also according age, breed, recurrent infections, if any concomitant signs as AR, AC (typical signs of atopy) and seasonability
- In vitro diagnostic - Easier and more reliable. Polyclonal Ab for detection of allergen specific IgE in serum
- Intradermal skin test
What are differential diagnostics to keep in mind before diagnosis with atopic dermatitis?
- Sarcoptic mange - similar to atopy and has to be ruled out before with skin scraping and treatment
- FAD
- Bacterial pyoderma
- Malassezia dermatitis
- CAFR (Cutaenous Adverse Food Reactions)
- Demodicosis
How is atopic dermatitis treated?
There is no cure and the condition needs a life long management as a combination of treatments
- Allergen specific immunotherapy by application of allergen extracts in arising levels by skin test or serology – causing a modulation of suppressor and T-helper cells and a shift of immune response, in 60-80% its effective in young dogs.
- Antihistamines – Not as effective in dogs as in humans but can be given to patient with not so bad pruritus.
- Glucocorticoids – Methylprednisolone. Only used in cats since showing less side effects than dogs.
- Oclacitinib – Recommended for allergy, atopy, flea dermatitis. Good drug to stop it quickly. Not so common with side effects and drug of choice many times. Give 0,4 – 0,6mg/kg x2 a day for 14 days P.O, then 1 tablet a day. Very effective already after one pill.
- Lokivetmab – caninised monoclonal Ab targeting IL-31. Decreases pruritus and inflammation in body. Very effective. Given S.C. In patients up to 1 year and less than 2kg it is not used as antiallergic treatment and instead corticosteroids.
- Essential fatty acids – Used as supportive treatment in combination with antihistamine to enhance the effect, long term treatment. Effective to leukotrienes and prostaglandin synthesis – changing skin lipids and modulation of lymphocyte function.
What is flea allergy?
- Combination of type I and IV hypersensitivity reaction.
- No breed disposition
- Can be trigged by presence of only one fly
What is the age predisposition of flea allergy?
Develop usually between age 3 - 6 years old
What are clinical signs of flea allergy?
Popular-crust lesions
- Often found on tail, on lumbosacral regopin
- In chronic course can se HYPERPIGMENTATION
What type of hypersensitivity is food hypersensitivity?
Type I hypersensitivity (allergy)
What type of hypersensitivity is contact dermatitis and why does it occur?
- Hypersensitivity type IV (allergy)
- Sensitivity induced by bacteria, viruses, chemical substances parasites, that bind to body proteins and thus form new antigens that are responsible for skin reaction.
*The slow reaction occurs in 24 – 72h.
