Gross chapter 16/71 - Pustular and nodular diseases of hair follicles

Question 1

True luminal neutrophilic folliculitis is often not evident in feline dermatophytosis, true or false?

Answer 1

True

Question 2

True or false, it is not uncommon for only a single hair to be affected in a given biopsy specimen of feline dermatophytosis.

Answer 2

True

Question 3

Which special stain should be considered in any uninflamed specimen of feline skin if scaling or alopecia are reported clinically?

Answer 3

PAS/GMS for dermatophytes

Question 4

A nodular lesion of focally extensive furunculosis due to dermatophytes in a dog is referred to as a what?

Answer 4

Kerion

Question 5

At which level(s) of the hair shaft can pustules form in canine pemphigus foliaceus?

Answer 5

Follicular infundibula or less commonly as deep as the isthmus.

Question 6

What does panfollicular pemphigus mean?

Answer 6

Follicular pustules often form in a ‘subcorneal’ location, i.e. beneath the keratin lining the outer root sheath, and may extend through the entire wall of the follicle

Question 7

In large furuncules in deep bacterial folliculitis, neutrophils, eosinophils, and macrophages tend to localize at the center of these inflammatory foci, whereas which cells are found at the periphery?

Answer 7

Plasma cells

Question 8

In deep bacterial folliculitis and furunculosis, bacteria can be seen where?

a) in the keratin of superficial follicles
b) in severely inflamed foci

Answer 8

In the keratin of superficial follicles

Question 9

Frank cellulitis more often accompanies furuncles in which disease process?

Answer 9

Demodicosis

Question 10

At which body sites does GSD pyoderma typically begin?

Answer 10

The lateral surface of the hindlegs and the lumbosacral region

Question 11

Which body sites are most typically affected in GSD pyoderma?

Answer 11

The lateral thighs, rump, back, ventral abdomen, elbows, and distal extremities.

The chest wall and neck are additional severely affected sites, and the perioral region also may be affected.

Question 12

Hemorrhagic bullae, the hallmark feature of GSDP, consist of what histopathological findings?

Answer 12

Large pustules in the superficial to middle dermis, accompanied by severe hemorrhage. Early hemorrhagic bullae may exclude follicular involvement and are often localized strikingly in interfollicular spaces

Question 13

Which body site is most severely affected in post-grooming furunculosis?

Answer 13

The dorsal midline of the trunk often is most severely affected, supporting back-grooming as a trigger, as larger dorsal hairs may perforate hair follicles more readily.

Question 14

Within what time frame do lesions of post-grooming furunculosis appear?

Answer 14

24-48 hours

Question 15

In post-grooming furunculosis, furuncules are often surprisingly

a) deep
b) superficial

Answer 15

Superficial

Question 16

Name two histopathological features of acral lick lesions.

Answer 16

Severe acanthosis, ulceration, vertical streaking fibrosis, and perihidradenitis. There may be traumatic furunculosis. Free keratin and hair shafts are often displaced well beneath the level of the hair follicles (hair may be found in the superficial subcutis). Inflammation is generally deep as well, and may progress to cellulitis (diffuse inflammation of the subcutis) in severe cases.

Question 17

Name two breeds of dog that are more likely to develop actinic furunculosis.

Answer 17

Dalmatians, Whippets, Italian Greyhounds, Greyhounds, American Staffordshire Terriers, Bull Terriers, Beagles, and Basset Hounds

Question 18

Which feature can be used to identify the skin of the chin?

Answer 18

Large sebaceous glands

Question 19

Which species of dermatophyte is most typically associated with kerion formation in dogs?

Answer 19

M. gypseum

Also seen with T. mentagrophytes and M. canis

Question 20

What histopathological findings are associated with occult demodicosis in dogs?

Answer 20

Discrete parafollicular granulomas or pyogranulomas, often containing giant cells, may organise adjacent to or beneath hair follicles, or within sebaceous glands or ducts.

Question 21

In cats, luminal pustular folliculitis is most often associated with:
Dermatophytosis
Demodicosis

Answer 21

Dermatophytosis

Question 22

Can Pelodera dermatitis be diagnosed on skin scrapings?

Answer 22

Yes - Skin scrapings should readily reveal motile nematode larvae measuring approximately 600 um in length.

Question 23

Which other body sites have reportedly been affected in cases of eosinophilic furunculosis of the face?

Answer 23

Lesions commonly are localised in a somewhat bilaterally symmetric pattern on the dorsal and lateral muzzle and periorbitally. However, similar lesions may be seen on the comparatively glabrous skin of the axillae and ventral abdomen, thoracic wall, distal legs, lips, and pinnae.

Question 24

How can you differentiate eosinophilic furunculosis of the face from facially-orientated autoimmune skin diseases such as PF?

Answer 24

Eosinophilic furunculosis is a fulminant, peracute dermatosis, whereas autoimmune skin diseases commonly develop gradually from subtle beginnings.