Intro to Dermatology and Diagnostic methods Flashcards
- Pruritus and causes.
- With what disorders can scale be seen?
- What is alopecia?
- What is a bulla?
- Itching - allergy, parasites, microbial infection/overgrowth, otitis.
- Keratinisation disorders.
- Hair loss - can be secondary.
- Localised collection of fluid >1cm in diameter and larger than a vesicle.
- What is erythema?
- What is a macule?
- A diffuse or localised redness of the skin which disappears with diascopy.
- A flat circumscribed skin discolouration <1cm in diameter without surface elevation or depression.
- 2 main causes of skin being red?
- How can these be differentiated?
- Erythema = blood in blood vessels. Haemorrhage = blood outside of blood vessels.
- Diascopy - place glass slide over the area of redness.
Erythema will blanch as vessels are compressed, haemorrhage will not blanch.
- What is a nodule?
- What is a papule?
- Circumscribed solid elevation greater than 1cm usually extending into the dermis, large nodules may be referred to as masses.
- A small solid elevation of the skin up to 1cm in diameter, feels solid and is due to the infiltration of inflammatory cells, fluid or foreign material, w/ oedema and epidermal hyperplasia.
- What is a patch?
- What is a plaque?
- What is a pustule?
- A localised flat change in the skin pigmentation larger than 1cm in diameter (big macule).
- Flat topped elevation of the skin >0.5cm formed by a coalition of papules; flatter than a nodule.
- A small circumscribed elevation of the epidermis filled w/ purulent material.
- What is a vesicle?
- What is a wheal?
- Small circumscribed elevation of the epidermis fille with a clear fluid <1cm in diameter.
- A sharply circumscribed raised lesion consisting of oedema; usually appears and disappears w/in minutes to hours.
Causes of secondary lesions.
Scratching, chewing, other trauma.
- as a result of infections or may evolve from regressing primary lesions.
- What is a comedone?
- What is crust?
- What is an epidermal collarette?
- Dilated hair follicle filled w/ cornified cells and sebaceous material. Blackheads.
- Dried exudate, cells, pus and scale adherent to the surface.
- A circular lesion w/ a marginal rim of scale.
- Excoriation/ erosion?
- Fissure?
- Hyperpigmentation.
- Hypopigmentation.
- Superficial damage to the epidermis.
- Linear cleavage into the epidermis.
- Too much pigment.
- Too little pigment.
- Hyperkeratosis?
- Lichenification?
- Increase in thickness of the cornified layer of the skin.
- Thickening of the skin as a whole resulting in cobblestone appearance.
- What is scale?
- Scar?
- Ulcer / ulceration?
- Accumulation of loose fragments of cornified layer of the skin.
- Fibrous replacement tissue formed when there has been trauma.
- Full thickness loss of epidermis, exposing the dermis.
Diagnostic approach of a dermatological case.
General history:
- other body systems affected.
- concurrent disease.
- lifestyle and exposure:
– environment.
– contagion.
- in-contact people and animals.
– contagion and zoonosis.
- diet.
Ectoparasite control.
Identify primary problem.
First sign?
Progression?
- lesion development.
- severity.
Chronic disease.
- seasonal.
- wax and wane.
Response to Tx.
- used appropriately?
Diagnostic techniques in dermatology.
Acetate tape:
- Malassezia, bacteria, inflammatory cells.
Skin scraping:
- Deep – demodex mites.
- Superficial – Cheyletiella, Sarcoptes, Chorioptes, Psoroptes (livestock).
Cytology.
Flea comb - fleas, Cheyletiella.
Trichogram (hair pluck) - demodex, anagen, telogen, mite and lice eggs, evidence of pruritus, dermatophytosis (ringworm), hair shaft abnormalities.
Advantages of cytology.
Quick, easy, cheap.
Gives a lot of info about what dealing with.
How would a skin scrape be taken from a larger animal e.g. horse w/ itchy distal limb.
Wooden tongue depressors to scrape material from skin surface into a petri dish.