Framework for dermatology

• What are the main dermatological presentations?

  Pruritus

  Ulcerative disease

  Non-pruritic

  Draining sinuses

  Ear disease

  Cutaneous masses.

  Crusting

  Claw disease
• Primary lesion morphology

  E.g. Papules, pustules, follicular casts.

  Often transient.
• Secondary lesion morphology

  e.g. Crusts

  • Result from primary lesion or external factor.
  • May be useful diagnostically.
• What does bilateral distribution of lesions mean?

  If bilateral then the lesion is much more likely to be a systemic problem originating from inside the animal.
• What does unilateral distribution of lesions mean?

  Asymmetric, irregular distribution of a lesion indicated the problem was caused by an external factor. External factors are very unlikely to cause a bilateral problem.
• What are common dermatological diagnoses in dogs?

  Ectoparasites

  Infections

  • Staphylococci
  • Malassezia
  • Dermatophytes (ring worm)
  • Viral/protozoal
  • Allergic
  • Neoplastic
  • Endocrine
• What are common dermatological diagnoses in cats?

  Ectoparasites

  Infections:

  • Dermatophytes
  • Viral
  • Staphylococci
  • Malassezia

  Allergic

  Neoplastic
• What does a coat comb/brush test show?

  Surface parasites/fleas.

  With or without liquid paraffin.
• What pathogens do you see with an acetate strip?

  Surface parasites.

  Use liquid paraffin, view on x4-10
• What pathogens do you see with deep skin scrapings?

  Deep parasites.

  Use liquid paraffin, view on x4-10
• What pathogens do you see with superficial skin scrapings?

  Surface parasites.

  Use liquid paraffin, view on x4-10
• What pathogens do you see with Trichograms?

  Demodex canis/cati, louse/Cheyletiella eggs.

  Dermatophytes on shaft (low sensitivity).

  Anagen/telogen bulbs, shaft/tip abnormalities (hair structure).

  Use liquid paraffin and view on x4-40.
• What pathogens do you see with Cytology (stained acetate strip/impression smear/ear smear)?

  Bacteria, yeasts.

  Other cells (e.g. inflammatory/epithelial/neoplastic).

  Stain the slide.

  View on x4-100 (oil).
• What pathogens do you see with Wood’s lamb?

  Some Microsporum canis
• What pathogens do you see with McKenzie coat brush?

  Dermatophytes for culture.
• What pathogens do you see with microbiological swab for culture?

  Bacteria, yeasts
• What sample would you take if you have a wet/greasy lesion that is inaccessible with a slide?

  Indirect impression smear

  • Use a cotton bud in the ear Cana,, roll onto the slide not drag.
• What sample would you take if you have a wet/greasy lesion that is accessible with a slide?

  Direct impression smear - press slide onto the lesion.
• What sample would you take if you have a dry lesion?

  Stained acetate tape strip:

  • Scale, erythema, lichenification
  • Non-greasy skin folds
  • Interdigital
• What sample would you take to investigate the presence of bacteria on the surface of an exudation plaque?

  Direct impression smear.