Pruritis and Alopecia Flashcards
(29 cards)
Axons that mediate the ‘sensation’ of pain or itch are _______ ______.
Unmyelinated axons [C fibers]
Cell bodies for itch are located in the ________ ________ _______ of spinal nerves & the _______ ________ of CN V for the face.
Dorsal root ganglia, Trigeminal ganglion
In the white matter of the dorsal horn, there are bundles of cords called the ________ ______ that receive incoming action potentials (for pain) and transmit them to the brain.
Spinothalamic tract
The brain’s itch processing centers have been preliminarily identified as the ________ ________ _______.
Primary somatosensory cortex
Itch neurons intersect or intercommunicate with other neurons, esp. those that mediate _______.
Pain
The mediator of pruritis is _______; released by mast cells but we know there are other mediators involved as well.
Histamine
The 3 major causes of pruritis in a dog are?
- Allergies, 2. Ectoparasites, 3. Infections
The 4 major allergies that cause pruritis?
- Flea allergy
- Atopic dermatitis
- Cutaneous adverse food reaction
- Insect bite hypersensitivity/contact dermatitis
The 5 major ectoparasites that cause pruritis in a dog are what?
- Sarcoptes
- Demodex (although pyoderma is what triggers the itch in dogs)
- Cheyletiella [walking dandruff]
- Lice
- Chiggers
The 3 major infections that cause pruritis in a dog is?
- Pyoderma, 2. Yeast (mallazessia) and 3. Dermatophytes (Trichophyton and Microsporum)
The two common locations on the body effected by Sarcoptic mange are?
- Elbows and 2. Ears (they will have a positive pinna-pedal reflex)
Are flea allergy, atopy, and insect allergy considered seasonal?
Yes, except flea allergy and atopy which can occur year round in states without seasons like FL and CA.
T/F: When grading pruritis on a scale of 1-10, 10 would be considered the absolute worst.
True [this type of pruritis is the kind that wakes the owner up in the middle of the night, and is digging on him/herself in the exam room, despite the fact that endogenous cortisol is typically released from stress at the vet, this is the time the pet should be least itchy, these grade 10 dogs will be itchy no matter what!]
The top 3 causes of the most severe pruritis 10/10 are:
- Scabies
- Flea allergy
- Food allergy
If pruritis came before the lesions you can expect it might be caused by which 2 things?
- Allergies
2. Scabies
If the lesion showed up before the pruritis, you can expect it might be from which 3 things?
- Demodicosis
- Dermatophytes
- Pyoderma
What are the 3 different types of skin lesions in cats?
- Bilaterally symmetrical hair loss with normal skin: non-inflammatory
- Miliary dermatitis
- Eosinophilic granuloma complex
What are 3 different inflammatory diseases that can effect the hair follicle?
- Folliculitis/pyoderma
- Ringworm
- Demodex
What are 2 different non-inflammatory diseases that can effect the hair follicle?
- Endocrine
2. Follicular dysplasias
Vibrissae and whiskers are a type of ________ hair.
Sinus [b/c they have an endothelium lined blood sinus, with rich nerve supply.]
Tylotrichs are specialized hair scattered among other hairs that act as ______ _______ ________.
Rapid acting mechanoreceptors
______ hairs are well anchored and do not pull out easily.
Telogen [this cycle dominates in most dogs, can remain in telogen for months to years.]
T/F: The presence of telogen indicates a pathologic state.
False
Hair replacement occurs in a ______ pattern.
Mosaic
