Eosinophilic plaque in Cats (Felis) | Vetlexicon
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Eosinophilic plaque

ISSN 2398-2950


Introduction

  • Cause: various hypersensitivity disorders or heritable.
  • Signs: erythematous, raised, exudative lesions anywhere on the body including oral cavity.
  • Diagnosis: history and clinical signs, and trial treatments for underlying causes.
  • Treatment: identification and correction of underlying cause. Symptomatic.
  • Prognosis: excellent if underlying disorder is identified and treated.

Presenting signs

  • Focal area of intense pruritus.
  • Erythematous, raised, exudative lesions anywhere on the skin but particularly on the ventral abdomen or the medial thighs   Linear granuloma  .
  • May be single or multiple.
  • May have a peripheral lymphadenopathy Lymphadenopathy.

Pathogenesis

Etiology

Hypersensitivity

Ectoparasites

Infection

Other causes

  • Genetic factors.

Pathophysiology

  • Hypersensitivity thought to be causative in most cases.
  • Inflammation (typically hypersensitivity or ectoparasites)   →   cellular infiltration by mast cells and eosinophils.
  • Mast cell degranulation   →   release of eosinophil chemotactic factors.
  • Eosinophilic granules   →   down regulation of inflammation, parasite destruction and collagenolysis.
  • Self trauma   →   ulceration   →   2° bacterial infection.

Diagnosis

Presenting problems

  • Ulceration.
  • Pruritus.

Client history

  • Pruritus precedes development of lesions.
  • Single or multiple lesions anywhere on body.

Clinical signs

  • Focal area of intense pruritus.
  • Erythematous, well-circumscribed, raised lesions which are oozing and ulcerated. Round to oval 0.5-7cm in diameter.
  • Particularly ventral abdomen and medial thighs   Linear granuloma  though anywhere on the skin or mucocutaneous junctions. Also on oral cavity.
  • Ulcerated or crusted with a cobblestone appearance to the surface.
  • Peripheral lymphadenopathy is common.

Diagnostic investigation

Bacteriology
  • Carefully performed cultures are negative unless secondary bacterial infection.
  • Cultures are required if there are rods on cytology or if the cat has had previous antibiotic treatments.

Cytopathology

  • Impression smear may show eosinophils, +/- bacteria and neutrophils if secondary bacterial infection.

Histopathology

  • Spongiotic or hyperplastic epidermatitis +/- microvesicles in epidermis. Dermal infiltrate is diffuse or perivascular consisting primarily of eosinophils with fewer numbers of mast cells. There is no granuloma formation. Flame figures may be seen. There may be dermal mucinosis.

Hematology

Other

Confirmation of diagnosis

Discriminatory diagnostic features

  • Cytology.
  • Hematology.

Definitive diagnostic features

  • Histopathology.
  • Diagnosis of an underlying hypersensitivity/allergy.

Differential diagnosis

Treatment

Initial symptomatic treatment

Standard treatment

Ectoparasites

Hypersensitivity

Bacterial skin disease

Cases in which no cause can be identified
  • Oral antibiotics Therapeutics: antimicrobial drug 3-6 weeks therapy may give partial or total remission of some cases.
  • Systemic glucocorticoids Prednisolone if no response seen to oral antibiotics.
  • Injectable methylprednisolone Methylprednisolone, 4-5 mg/kg IM, max 20 mg in a dose q2 weeks until a beneficial response is seen (typically 2-3 treatments). Once in remission then q 2 months or discontinue if possible.
  • Oral glucocorticoids: High dose prednisolone Prednisolone1-2 mg/kg BID, once in remission 1 mg/kg q48h then after 2-3 weeks 1 mg/kg q 48h. Methylprednisolone Methylprednisolone 4 mg/kg q24h. Triamcinolone Triamcinolone 0.5-0.75 mg/kg q24h. If lesions resolve, taper to lowest possible alternate day dosage. (May be possible to taper triamcinolone to twice weekly.) Dexamethasone Dexamethasone (solution) 0.05-0.2 mg/kg every 1-3 days can also be used. For all these corticosteroids it is more effective to use a higher dose initially to obtain control of the lesion and to then reduce the dose only once the lesion has disappeared. Concurrent elimination of exposure to any antigen should also occur.
  • Immunomodulating drugs if no response to glucocorticoids.
    But beware serious side effects, eg bone marrow suppression.
  • Ciclosporin (cyclosporine) Ciclosporin 7 mg/kg/day (orally).
  • Chlorambucil Chlorambucil 0.1-0.2 mg/kg q24h reducing to q48h if beneficial response.
Megestrol acetate Megestrol acetate is not recommended because of potential side effects. Use only in cases unresponsive to any other therapies. Dose: 2.5-5 mg/cat q48h tapering to 2.5-5 mg q2-14 days.

Surgery

  • Surgery is not usually considered; it does not eliminate the underlying hypersensitivity and is unlikely to be curative.
  • Sharp surgical excision - may leave deformities.
  • Cryosurgery: Poor results.
  • Radiation therapy.
  • Laser therapy Laser therapy: overview .

Monitoring

  • Clinical signs.
  • If on long term glucocorticoid therapy then 6-12 monthly assessment of hematology, blood biochemistry and urinalysis to look for side effects.

Prevention

Outcomes

Prognosis

  • Variable dependent on whether an underlying cause has been found and corrected.
  • Long term symptomatic management usually required in cases where the underlying cause cannot be identified.

Expected response to treatment

  • Improvement over 3-6 weeks with treatment.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Wildermuth B E, Griffin C E & Rosenkrantz (2011) Response of feline eosinophilic plaques and lip ulcers to amoxicillin trihydrate-clavulanate potassium therapy: a randomized, double-blind placebo-controlled prospective study. Vet Dermatol 23 (2), 110-8 PubMed.
  • Lee M, Bosward K L, Norris J M (2010) Immunohistochemical evaluation of feline herpes-1 infection in feline eosinophilic dermatoses or stomatitis. J Feline Med Surg 12 (2), 72-79 PubMed.
  • Bardagí M, Fondati A, Fondevila D et al (2003) Ultrastructural study of cutaneous lesions in feline eosinoophilic granuloma complex. Vet Dermatol 14 (6), 297-303 PubMed.
  • Kimura T, Kano R, Maeda S et al (2003) Expression of RANTES mRNA in skin lesions of feline eosinophilic plaque. Vet Dermatol 14 (5), 269-273 PubMed.
  • Fondati A, Fondevila D & Ferrer L (2001) Histopathological study of feline eosinophilic dermatoses. Vet Dermatol 12 (6), 333-338 PubMed.
  • Scarampella F, Abramo F & Noli C (2001) Clinical and histological evaluation of an analogue of palmitoylethanolamide 120 (comicronized Palmidrol INN) in cats with eosinophilic granuloma and eosinophilic plaque - a pilot study. Vet Dermatol 12 (1), 29-39 PubMed.
  • Power H T, Ihrke P J (1995) Selected feline eosinophilic skin diseases. Vet Clin North Am Small Anim Pract 25 (4), 833-850 PubMed.
  • Moriello K A, Kunkle G, Miller L M et al (1990) Lack of autologous tissue transmission of eosinophilic plaques in cats. Am J Vet Res 51 (7), 995-998 PubMed.

Other sources of information

  • Miller W H, Griffin C E & Campbell K L (2013) Feline eosinophilic granuloma complex. In: Muller and Kirk's Small Animal Dermatology. Miller  WH, Griffin C E & Campbell K L (eds). Elsevier Mosby, St Louis, Missouri, pp 714.
  • Gross T et al (2005) Ulcerative and crusting dermatoses of the epidermis. In: Skin Diseases of the Dog and Cat, Clinical and Histopathologic Diagnosis. Ames Blackwell Science, pp 116.
  • Gross T et al (2005) Nodular and diffuse diseases of the dermis with prominent eosinophils, neutrophils or plasma cells. In: Skin Diseases of the Dog and Cat, Clinical and HIstopathologic Diagnosis. Ames Blackwell Science, pp 342.
  • Rosenkrantz W S (1992) Feline eosinophilic granuloma complex. In: Griffin C E, Kwochka K W, MacDonald J M (eds) Current Veterinary Dermatology: the Science and Art of Therapy. Mosby Year Book, St Louis, pp 319.