Dermatology cases Flashcards
Case 1:
Tigger is a 5 year old (MN) DSH cat.
His owner had noticed that the metatarsal pad of his left hind foot had become soft, swollen and paler in colour than normal.
Recently, he had been licking it and there was an ulcerated area on the pad.
On physical examination all other feet were normal.
- He is quiet, alert and responsive.
- Heart rate = 140bpm, Respiratory rate 25bpm, Temperature 39.5C.
- No other abnormalities detected on
What are you differentials for this case?
- Bacterial or fungal granuloma
- Collagenolytic (eosinophilic) granuloma
- Squamous cell carcinoma
- Feline herpesvirus or calicivirus respiratory infection
- Plasma cell pododermatitis
- Burns e.g. caustic or thermal
- Immune Mediated Disease e.g. pemphigus foliaceus
Case 1:
Tigger is a 5 year old (MN) DSH cat.
His owner had noticed that the metatarsal pad of his left hind foot had become soft, swollen and paler in colour than normal.
Recently, he had been licking it and there was an ulcerated area on the pad.
On physical examination all other feet were normal.
He is quiet, alert and responsive.
Heart rate = 140bpm, Respiratory rate 25bpm, Temperature 39.5C.
No other abnormalities detected on
The clinical appearance of this case is highly suggestive of plasma cell pododermatitis.
What should you do next?
What is the prognosis?
- Biopsy is required for definitive diagnosis.
- Early lesions show perivascular dermatitis with numerous plasma cells.
- Older lesions demonstrate diffuse plasmacytic dermatitis. Oedema may be visible vessels may appear more prominent. Exudative ulceration and erosian may be present. High levels of neutrophils may reflect secondary infection.
- Biopsy’s are useful at ruling in/out differentials. For example with herpesvirus/calicivirus you would expect viral inclusion bodies to be present.
What is the prognosis?
- Good
Is pododermatitis due to immune mediated pathogenesis?
Can plasma cell pododermatitis can resolve without any treatment in certain cases?
Is pododermatitis due to immune mediated pathogenesis?
Yes
Can plasma cell pododermatitis can resolve without any treatment in certain cases?
Yes some cases resolve spontaneously without treatment
Does plasma cell pododermatitis only affect the foot pad?
Can initial lesions be painless and often unnoticed?
Does plasma cell pododermatitis only affect the foot pad?
No, although it primarily affects the feet, (metacarpal and metatarsal pads), lesions can be seen on the tip of the nose
Can initial lesions be painless and often unnoticed?
Yes
Case 2:
Scruff is a 1 year old crossbred dog.
He presented in August with a two week history of chewing and licking at his front feet.
His owner thought that he was sensitive to grass so had stopped walking him across the fields, with no improvement.
What questions would you like to ask Scruff’s owner?
Family history
- Dietary history
- Pets normal environment
- Any recent environmental changes
- Drug/insecticide history
- Areas of the body historically affected
- Type of lesions that originally occurred
- Response to previous therapies
- Exposure to possible irritants
- Pruritus status of other family members and pets
Case 2:
Scruff is a 1 year old crossbred dog.
He presented in August with a two week history of chewing and licking at his front feet.
His owner thought that he was sensitive to grass so had stopped walking him across the fields, with no improvement.
On further questioning, Scruff’s owner reveals he has had mild episodes of otitis which responded to routine treatment
On general physical examination there are no abnormalities detected.
What are your top three differentials for this case?
What are your top three differentials for this case?
HAS TO BE ON THE LIST:
Atopy
Any of two from the following:
Neotrombicula autumnalis infestation (Harvest mite)
Contact or irritant dermatitis
Cutaenous Adverse Food Reaction
Case 2:
Scruff is a 1 year old crossbred dog.
He presented in August with a two week history of chewing and licking at his front feet.
His owner thought that he was sensitive to grass so had stopped walking him across the fields, with no improvement.
On further questioning, Scruff’s owner reveals he has had mild episodes of otitis which responded to routine treatment
On general physical examination there are no abnormalities detected.
However whilst having a more thorough look at Scruff’s feet, you observe the following:
Harvest mite infestation is typically seen in the late summer and autumn.
Diagnosis is based on visualisation of the orange mites.
It can also affect the head and flank.
What are your treatment options?
Many antiparasitic agents are effective against Neotrombicula autumnalis (although not licensed). E.g. Fipronil and Selamectin
Other considerations to make:
If a persistent hypersensitivity reaction exists or the mites cannot be eliminated, you may consider prescribing anti-inflammatories.
Antibiotics may be required if secondary infection is present.
Link the parasites with the findings:
Discuss Microsporum dermatophytosis infection:
Some strains of microsporum canis can be diagnosed with the use of an ultra-violet source to detect apple green fluorescence. However care should be taken to distinguish green fluorence from the bluish appearance of dust and scale. False negatives are also common therefore material should also be collected from the advancing margin of lesions, for microscopic examination and for fungal culture.
Discuss Sarcoptes scabiei infestation:
Diagnosis can be supported with a positive pinnal scratch reflex. Scabies is caused by Sarcoptes scabiei canis. Deep skin scrapings can be diagnostic, but be aware false negatives are very common as even small numbers of the mite can result in significant pruritus. Serum IgG titres can also be a useful diagnostic test, but false positives and negatives can occur.
Discuss Cheyletiella infestation:
Cheyletiella mite is visible to the naked eye. It is highly contagious and commonly causes problems in kennels, pet shops etc. Coat brushings, superficial skin scrapings or examination of unstained acetate tape strips can help in diagnosis, but false negatives can still occur.
Discuss Flea infestation:
Flea infestation often show pruritus affecting the dorsal and caudal aspect of the animal.
Flea faeces can also be detected as brown/black dirt that forms a reddish-brown colour when placed on wet paper. However, false negatives can be common.
Discuss Hookworm infestation:
Definitively diagnosed by nematode eggs in faeces. However a history of poor hygiene or use of grass runs will also support diagnosis.
Despite diagnostic testing sarcoptes scabiei, cheyletiella and flea infestations can only be ruled out after therapeutic trials.
Case 3: Canine alopecia Elsie
You see on your computer that your next appointment is an 8 year old female neutered Staffordshire Bull Terrier named Elsie.
Today’s appointment was booked as a 3 month medication check for Epiphen tablets.
What is the active ingredient of these tablets? Knowing this, what condition does Elsie most likely have?
Elsie has idiopathic epilepsy and so is on daily phenobarbital.
You see on your computer that your next appointment is an 8 year old female neutered Staffordshire Bull Terrier named Elsie.
Today’s appointment was booked as a 3 month medication check for Epiphen tablets.
What is the active ingredient of these tablets? Knowing this, what condition does Elsie most likely have?
Elsie has idiopathic epilepsy and so is on daily phenobarbital.
You invite Elsie and her owners into your consult room and determine that Elsie’s seizures are being well controlled and you can safely prescribe more phenobarbital.
While chatting with her owners, you discover they are concerned that Elsie has some recent onset hair loss.
You determine that Elsie is not pruritic.
Although not the case with Elsie, alopecia due to the animal licking, scratching, or chewing off the hair is very common.
Think about the most likely causes of this. If Elsie was pruritic, what would your top differentals be for alopecia secondary to pruritus?
Allergies eg. atopy, food allergy, contact allergy, fleas (flea allergy dermatits)
Ectoparasites eg. mites, lice
Microbial infections e.g. Malassezia dermatitis and pyoderma (doesn’t always cause pruritus)
Dermatophytosis - variably pruritic
Elsie has non-pruritic alopecia, this can be subdivided into inflammatory and non-inflammatory causes. Can you divide these causes into their categories?
