Eosinophilic granuloma in Cats (Felis) | Vetlexicon
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Eosinophilic granuloma

ISSN 2398-2950


  • Cause: various hypersensitivity disorders or heritable.
  • Signs: linear or nodular lesions on the skin or 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

  • Linear or nodular lesions, anywhere on the skin   Skin: eosinophilic plaque on flank  Eosinophilic plaque  or in the oral cavity   Skin: eosinophilic granuloma - mouth  Skin: eosinophilic ulcer on mouth - DSH  Skin: eosinophilic granuloma in lip  Mouth: eosinophilic granuloma complex  Mouth: normal  .
  • No pain or pruritus.

Age predisposition

  • 0.5-5 years.






Other causes

  • Genetic factors.


  • 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.


Presenting problems

  • Ulceration.
  • Pruritus is unusual.
  • Nodules.
  • Papules.

Client history

  • Asymptomatic chin swelling.
  • Skin lesions with associated pruritus.

Clinical signs

  • Linear or nodular lesion.
  • Raised cord-like bands 2-4 mm wide and 5-10 mm long of pink-yellow, firm, alopecic areas extending along the posterior aspect of the hindlimbs.
  • No pain or pruritus.
  • Well circumscribed papules, nodules or plaques.
  • Asymptomatic chin swelling = feline chin edema.
  • Oral lesions  Skin: eosinophilic plaque on flank   Skin: eosinophilic granuloma - mouth   Skin: eosinophilic ulcer on mouth - DSH , smooth, glistening, nodular and usually non-ulcerated, especially pharynx and tongue   Mouth: eosinophilic granuloma on tongue   Mouth: eosinophilic granuloma complex .
  • Anywhere on skin, mucocutaneous junction or oral cavity, erosion or ulceration.
  • White speckling of eroded surface - corresponds to collagen degeneration.
  • Lower limb swellings or nodules.
  • Swelling of the bridge of the nose, pinnae or foot pads (mosquito bite hypersensitivity).
  • Peripheral lymphadenopathy.
  • Lip ulceration.
  • Eosinophilic plaque.
  • Pruritus.

Diagnostic investigation


  • Carefully performed cultures are negative.


  • Impression smear, superficial skin scrape or fine needle aspirate for nodules, may show high numbers of eosinophils, +/- bacteria and neutrophils if secondary bacterial infection.


  • Nodular to diffuse, granulomatous dermatitis with multifocal areas of collagen degeneration. Eosinophils and multi-nucleated, histiocytic giant cells are common and flame figures may be seen. Mucinosis of the dermis and outer root sheath, focal eosinophilic folliculitis, furunculosis or panniculitis may be present.


  • Eosinophilia may be seen.


  • Flea comb to look for fleas or flea feces.
Many cats with flea bite hypersensitivity are overgrooming and no flea fecal material is found. It can be worthwhile checking other household cats for signs of flea presence.

Confirmation of diagnosis

Discriminatory diagnostic features

  • Cytology.
  • Hematology.

Definitive diagnostic features

  • Histopathology.

Differential diagnosis


Initial symptomatic treatment

Standard treatment



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 Prednisolone 5 mg/kg q24h, once in remission 2mg/kg q48h. 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.Megestrol acetate Megestrol acetate is not recommended because of potential side effects. Use only in cases unresponsive to any other therapies. Dose: 2.5-5mg/cat q48h tapering to 2.5-5mg q7-14 days.
  • Immunomodulating drugs if no response to glucocorticoids.
    But beware serious side effects, eg bone marrow suppression.
  • Chlorambucil Chlorambucil 0.1-0.2 mg/kg q24h reducing to q48h if beneficial response.


  • Sharp surgical excision - may leave deformities.
  • Cryosurgery: Poor results.
  • Radiation therapy.
  • Laser therapy.


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




  • Some cases in younger cats seem to spontaneously resolve over a few months.
  • Otherwise, 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


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Leistra W H, van Oost B A & Willemse T (2005) Non-pruritic granuloma in Norwegian Forrest cats. Vet Rec 156 (18), 575-577 PubMed.
  • Bardagí M, Fondati A, Fondevila et al (2003) Ultrastructural study of cutaneous lesions in feline eosinophilic granuloma complex. Vet Dermatol 14 (6), 297-303 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.
  • Mason K V & Evans A G (1991) Mosquito bite-caused eosinophilic dermatitis in cats. JAVMA 198 (12), 2086-2088 PubMed.
  • Pentlarge V (1991) Eosinophilic conjunctivitis in five cats. JAAHA 27 (1), 21-28 VetMedResource.
  • Manning T O, Crane S W, Scheidt V J et al (1987) Three cases of feline eosinophilic granuloma complex (eosinophilic ulcer) and observations on laser therapy. Semin Vet Med Surg (Small Anim) (3), 206-211 PubMed.
  • Gelberg H B, Lewis R M, Felsburg P J et al (1985) Antiepithelial autoantibodies associated with the feline eosinophilic granuloma complex. Am J Vet Res 46 (1), 263-265 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. Eds: Miller W H, Griffin C E & Campbell K L. 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: Current Veterinary Dermatology the science and art of therapy. Eds: Griffin C E, Kwochka K W, MacDonald J M. Mosby Year Book, St Louis pp 319.
  • Power H (1990) Eosinophilic granuloma in a family of specific pathogen-free cats. In: Proceedings of the Annual Members Meeting of the American Academy of Veterinary Dermatology and American College of Veterinary Dermatology.