(04) - Pemphigus Foliaceous

Question 1

1. Pemphigus foliaceous and discoid lupus erythematous are the most common autoimmune diseases of dogs and cats. You will see them!
2. Autoimmunity is a condition characterized by a specific humoral or cell-mediated immune response against the body’s own tissue.

Answer 1

d

Question 2

1. Crusts, erosions, ulcers, pustules, vesicles, bulla and papules are lesions often present in autoimmune diseases.
2. What body parts are frequently affected in pemphigus foliaceous or erythematous and discoid lupus erythematous?
3. Footpads are often affected in what?
4. Mucocutaneous junctions (oral, ocular and genital) are often affected in pemphigus vulgaris and bullous pemphigoid.
5. Total body can be affected in some cases

Answer 2

2. The planum nasal and bridge of the nose

3. pemphigus foliaceous

Question 3

1. History and clinical signs (type and distribution of lesions) are very helpful.
2. Histopathology is essential and is diagnostic most of the time.
3. Cytologic exam of direct smears from intact pustules, vesicles, bulla or from recent erosions or crusted lesions can be diagnostic of pemphigus if it demonstrates nondegenerated neutrophils, +/- eosinophils and numerous acanthocytes. Remember, however, that acantholytic cells can also be seen with some cases of dermatophytosis and severe pyoderma.

Answer 3

d

Question 4

1. Direct immunofluorescence and immunoperoxidase can be helpful if histopathology was not diagnostic.
   However, many false negative results can occur. False positive results often occur when what are sampled?
2. CBC, chemistry profiles and urinalyses are important to be performed to check for what?
3. ANA is highly sensitive (positive in 90% of SLE cases) but what?

Answer 4

1. planum nasal and footpads are sampled.
2. systemic involvement (SLE) - ( to monitor for potential side effects associated with immunosuppressive therapies.)
3. has low specificity (many false positive results)

Question 5

1. Biopsy primary lesions such as intact pustules, vesicles and/or bulla when possible.
2. If these lesions are not present, biopsy an early papule, fresh erosion and/or crusted lesion (do not
   remove the crust)
3. Obtain several samples (3 to 5). It is always helpful to biopsy different stages of disease development
4. Do not prep the skin as this will destroy the lesion.

5. Do not pinch, squeeze or even grab the skin sample; this will damage the tissue and change the 
histopathologic features (I often use my fingers to grab the sample instead of a forceps). 

6. Quickly place the sample into the formalin.
7. DO NOT treat without a diagnosis – the animal will be treated for life with medications that potentially can cause severe side effects.

Answer 5

d

Question 6

1. For immunofluorescence and immunoperoxidase biopsy intact vesicles and pustules and perilesional skin (but, do not sample normal skin).
2. Do not surgically prepare the skin.
3. Avoid old and chronic lesions.
4. For immunofluorescence, place your sample in Michel’s fixative and mail at room temperature
5.  For immunoperoxidase, place your sample in what?

Answer 6

5. formalin

Question 7

1. Common reasons for false negative results on histopathology and/or immunofluorescence are what?

Answer 7

1. absence of recent lesions; improper selection and handling of biopsies; loss of antigenicity of immunoglobulin deposits; prior steroid therapy.

Question 8

1. Pemphigus foliaceus is the most common autoimmune skin disease of dogs and cats.

Answer 8

d

Question 9

1. Pustules (transient), vesicles (transient), crusts (often seen), erosions, scales and erythema are localized to what body area?
2. can total body involvement occur?
3. Footpads (hyperkeratosis) are often affected and can be the only area involved in few cases.
4. Cats often develop inflammation of what?
5. Does oral mucosal involvement occur?

Answer 9

1. dorsal of the nose, planum nasal, and ear pinnae
2. yes
3. the nail bed (paronychia).
4. NONONONONONONO

Question 10

1. History and clinical signs (crusts on dorsal nose, planum nasal, ear pinnae, and footpads) are helpful diagnostic information.
2. Cytologic exam of direct smear from an intact pustule (rarely possible) or from the exudate present underneath a recent crust reveal nondegenerated neutrophils, often eosinophils and many acanthocytes (if not present, not diagnostic).
3. What is the most important diagnostic test?

Answer 10

3. histopathology (reveals a subcorneal pustule containing neutrophils, +/- eosinophils and many acanthocytes)

Question 11

1. Direct and indirect immunofluorescence tests are not frequently used as a diagnostic tool because why?
2. Remember! Do not biopsy planum nasal or footpads for direct immunofluorescence because why?
3. CBC can show what?
4. ANA is negative

Answer 11

1. false negative results are common
2. these sites are often positive in normal dogs (false positive)
3. leukocytosis