FELINE PLASMOCYTARY PODODERMATITIS. AN UPDATED VISION.

Pododermatitis plasmocitaria
 

Author: Laura Ordeix Esteve

Lda. Vet., MSc., PhD., Dipl. ECVD, EBVS® European Diploma Specialist in Veterinary Dermatology, Head of the Dermatology Service of the Fundació Hospital Clínic Veterinari – UAB and Associate Professor of the Department of Animal Surgery and Medicine of the UAB .

In this article, Laura Ordeix Esteve reviews the clinicopathological characteristics as well as the diagnosis and treatment of feline plasma cell pododermatitis (PPF). An immune-mediated entity that, although rare, represents a specific cutaneous reaction pattern of the feline species with probably different triggering causes. We aim pododermatitis plasmocytaria It is a rare disease of cats.1,2. However, it has two characteristics that make it a very interesting entity. On the one hand, It is a very specific condition of the feline species because there is no comparable clinical situation in the dog. This may suggest that either the cause is some event that only happens in cats, or the way in which the organism reacts to the same cause is different between the two species. On the other hand, this condition usually presents as a single episode, and affected cats rarely present recurrent symptoms. This can suggest that the triggering cause is related to a specific event.

Etiology and Pathogenesis of Plasmocyte Pododermatitis.

Unfortunately, the etiology and pathogenesis are unknown.1,2 of plasma cell pododermatitis. This sickness typically characterized by marked plasma cell infiltration into the adipose tissue and dermis of the palmar/footpads of the cat. Plasma cells are mature B lymphocytes that become activated and secrete antibodies, usually in response to antigenic stimulation, such as infection or an inflammatory process.1. Besides, This condition is usually associated with hypergammaglobulinemia and responds to immunomodulatory treatment, which is why a dysfunction of the immune system is suggested as the most probable pathogenesis.1. The location of the lesions on the footpads may suggest close contact with an external stimulus as the cause of the disease. Many infectious organisms have been investigated as causative agents of PPF, but no clear associations have been found.3,4. There is evidence to suggest that retroviruses may be important triggers of this disease.5,6. In fact, published data suggests feline immunodeficiency virus (FIV) positivity rates of 44 to 63%.3,7. In one case, FIV was identified in inflammatory cells by immunohistochemistry (IHC).5. In another case, an association with the feline leukemia virus (FeLV) was described, also by IHC.6. The age of affected cats ranges from 6 months to 12 years and can be of any sex or breed, although Common European cats are generally the most affected1,7. Clinically, plasma cell pododermatitis characterized by softening and swelling of the pads1,2,7. In most cases, there is more than one pad affected. Typically, the pads affected are the metacarpals or central metatarsals, although the digital pads can also be affected. The swollen pads, soften in the center, are very pink or sometimes even purplish-violet in color with white streaks (Photos 1-2).
Pododermatitis plasmocitaria
Photo 1
Pododermatitis plasmocitaria
Photo 2
Pododermatitis plasmocitaria
Photo 3
In the most severe cases, ulceration with herniation of the underlying inflamed fatty tissue appears (Photo 3-4). In some cats, lameness is observed, probably associated with pain, lymphadenomegaly, fever, or apathy.1,2. Plasma cell infiltration has occasionally been described in regions other than the footpads, such as the oral mucosa (plasmacytic stomatitis) or the bridge of the nose, which is swollen, firm with or without ulceration.1,8,9 (Photos 5-6).
Pododermatitis plasmocitaria
Photo 4
Photo 5
Pododermatitis plasmocitaria
Photo 6

Diagnosis of Plasmocyte Pododermatitis.

The diagnosis of PPF is quite clinical because its appearance is very characteristic. Sometimes eosinophilic granuloma can be considered a differential diagnosis, as well as some infectious granulomas (especially fungal) the neoplasms, however, these diseases usually cause solitary lesions and not multi-pad lesions as in PPF. Faced with clinical suspicion of a feline PPF it will be advisable to carry out a screening test for retroviral infections as well as a serum hematological and biochemical analysis and a urinalysis, since a cat with concomitant immune-mediated glomerulonephritis and renal amyloidosis has also been described1. Faced with clinical suspicion of a feline PPF it will be advisable to carry out a screening test for retroviral infections as well as a serum hematological and biochemical analysis and a urinalysis, since a cat with concomitant immune-mediated glomerulonephritis and renal amyloidosis has also been described1. Faced with clinical suspicion of a feline PPF it will be advisable to carry out a screening test for retroviral infections as well as a serum hematological and biochemical analysis and a urinalysis, since a cat with concomitant immune-mediated glomerulonephritis and renal amyloidosis has also been described1.
Pododermatitis Plasmocitaria
Photo 7
Pododermatitis Plasmocitaria
Photo 8
Currently first-line treatment is doxycycline (10 mg/kg or 25 mg/cat) given daily and orally until pads appear normal, which can sometimes take 10 weeks.3,10. The beneficial effect is probably related to its immunomodulatory properties, however an anti-infective effect cannot be excluded due to its antibiotic activity. Doxycycline produces complete remission in one third of cats and improvement of lesions in 80%.3,10. Some cats require continuous treatment with doxycycline, while others require only sporadic treatment.. If a favorable response to doxycycline is not obtained, other options such as oral prednisolone or dexamethasone at immunosuppressive doses or oral cyclosporine may be an alternative. Surgical excision may be a last option for those cases with a single affected pad that does not respond to immunomodulatory treatments.1. The prognosis is usually good, except in cases of concomitant immune-mediated glomerulonephritis or subsequent renal or hepatic amyloidosis.1. In some cats, the disorder resolves spontaneously without treatment.1.

References

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