Veterinary Dermatology 1996, 7, 227-233 Case Report Feline urticaria pigmentosa in three related Sphinx cats CARL0 B. VITALE,* PETER J. IHRKE,? THIERRY OLIVRYtS and ANTHONY A. STANNARDt Veterinary Medical Teaching Hospital, ?Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California 9561 6, USA (Received 17 October 1995; accepted 14 March 1996) Abstract A pruritic maculopapular eruption with clinical and histological features similar to urticaria pigmentosa of humans is reported in three related Sphinx cats. All cats shared the same grandsire, had a juvenile onset of disease, and demonstrated similar historical, clinical and histological findings. Physical examination revealed widespread bilaterally symmetrical, erythematous, partially coalescing, crusted macules and papules on the trunk, limbs, neck and head. A few macules exhibited a dark brown pigmentation. Dermatographism could not be elicited in any of the cats. Histological examination of papules revealed the presence of a perivascular to diffuse dermal and subcutaneous infiltrate of well-differentiated mast cells. In one cat where systemic involvement was pursued, evidence of internal disease was not found. Keywords: cat, mastocytosis, urticaria pigmentosa. INTRODUCTION CASE REPORTS Mastocytosis is a heterogeneous group of diseases Cats I and 2 defined as an abnormal proliferation of mast cells in A 1.5-year-old intact grey and white female Sphinx various organs including skin, liver, spleen, kidney or cat (cat 1) was presented to the University of gastrointestinal tract. 1-5 The infiltrating mast cells California Veterinary Medical Teaching Hospital may exhibit a benign or malignant behaviour. The (VMTH) with an approximately 1-year history of symptoms of mastocytosis are related to the release of pruritic papular lesions. Previous corticosteroid mast-cell mediators in various organ^.^,^,^ In humans, therapy resulted in partial reduction of pruritus and these symptoms may include vomiting, diarrhoea, a decrease in the number of papules. Overall im- nausea, abdominal pain, flushing, pruritus, headache provement was not noted with previous flea control and diz~iness.~ or an elimination diet. The classification of mastocytosis in animals and Physical examination revealed an otherwise healthy humans is based upon specific clinicopathological cat with generalized, symmetrical hypotrichosis char- findings. 1-337 In humans, mastocytosis is divided into acteristic of this breed. The hairs, where present, were the following syndromes: indolent disease, mastocy- fine and located predominately on the head and distal tosis associated with blood or bone marrow involve- limbs. Multifocal, partially symmetrical erythema- ment, aggressive disease associated with lymphatic tous, partially coalescing macules and occasional involvement, and mast cell leukaemia. Currently, crusted papules were present on the ventrum, there is no generally accepted classification to extremities, head and neck (Fig. 1). Some of the categorize mastocytosis in animals, as classification macules exhibited a dark-brown pigmentation. Dif- systems have focused on mast cell tumours. This ferential diagnoses for these skin lesions included report describes a unique skin disease in three related allergic skin disease (flea, atopy, food, contact), Sphinx cats resembling a subset of human indolent scabies, bacterial folliculitis, drug reaction, cheyletiel- mastocytosis, termed urticaria pigmentosa (UP). losis, neoplasia, xanthoma and pemphigus foliaceus. Deep skin scrapings for ectoparasites and a derma- tophyte culture were negative. Dermatographism could not be elicited with vigorous stroking of the *Present address: Department of Medicine and Epidemiology, skin. A complete blood count (CBC) was performed School of Veterinary Medicine, University of California, Davis, CA 95616, USA and revealed neutrophilia (19 840 pL-') [Normal $Present address: Department of Companion Animal and Special 2500-1 1 300 pL-'], eosinophilia (1488 pL-') [Nor-' Species Medicine School of Veterinary Medicine, North Carolina ma1 0-1400 pL-'], and basophilia (992 pL-') [Nor- University Raleigh, NC 27606, USA mal 0-100 pL-']. All parameters in a serum biochem- Correspondence: C. Vitale. istry profile and urinalysis were within established 0 1996 Blackwell Science Ltd 227 228 C.B. Vitale et al. reference values. Feline leukaemia (ELISA) and feline Dermatographism could not be elicited with immunodeficiency virus tests were negative. Skin vigorous stroking of the skin. Deep skin scrapings biopsy specimens of papules were obtained from the for ectoparasites and a dermatophyte culture were trunk and fixed in 10% neutral buffered formalin, negative. A complete blood count revealed neutro- routinely processed, and stained with haematoxylin philia (26 892 pL-') and basophilia (972 pL-'). and eosin. Results of a serum biochemistry profile and urinalysis Histopathology of the skin demonstrated a mod- were within established normal limits. Feline leukae- erate to severe perivascular to diffuse infiltrate in the mia (ELISA) and feline immunodeficiency viral tests superficial and deep dermis (Fig. 2). The infiltrate was were negative. Skin biopsy specimens taken from the comprised mainly of a homogenous population of papular lesions on the trunk were fixed in 10% large mononuclear cells, with smaller numbers of neutral, buffered formalin, routinely processed, and eosinophils and neutrophils. A few large mono- stained with haematoxylin and eosin. nuclear cells were present in the panniculus. Giemsa The results of the skin biopsy demonstrated similar stain revealed these mononuclear cells to be meta- histological changes to those seen in cat 1 (Fig. 5). chromatically staining mast cells (Fig. 3). Giemsa stain revealed many metachromatically Cat 2, a 2.5-year-old castrated male Sphinx, and staining mast cells diffusely and perivascularly in sibling of cat 1, was presented on the same day with a the dermis. 2-year history similar to cat 1. Physical examination Based upon the clinical features and histopatholo- revealed multifocal, erythematous macules and occa- gical findings, a tentative diagnosis of feline urticaria sional crusted papules similar to cat 1. Some of the pigmentosa was made for both cats. The owner of macules were pigmented dark brown. Multiple cats 1 and 2 was reluctant to pursue further diag- papules were present in a strikingly bilaterally nostic testing. Homeopathic therapy was initiated by symmetrical, linear pattern on the lateral thorax the owner and the cats were subsequently lost to and abdomen (Fig. 4). follow-up. Figure 1. Diffuse erythematous, partially coalescing papules were scattered on the ventral abdominal and inguinal regions (cat 1). Figure 2. Mast cells were arranged in an intense perivascular to diffuse pattern (H & Ex 488). 0 1996 Blackwell Science Ltd, Veterinary Dermatology, 7, 221-233 Feline urticaria in three related Sphinx cats 229 Figure 3. Geimsa stain highlighted the perivascular mast cells (Geimsa x 610). Figure 4. In cat 2, coalescing papules spanned the lateral thorax and abdomen in a linear pattern. Figure 5. High magnification of the perivascular mast cells from cat 2 (H & Ex 610). treatment with oral amoxicillin and oral prednisolone Cat 3 had diminished the number of papules and lessened An 8-month-old intact female Sphinx cat was the pruritus. presented to the VMTH with a 1-month history of Physical examination revealed generalized bilater- pruritic papular lesions. This cat had the same ally symmetrical, erythematous and brownish ma- grandsire as cat 1 and 2. Historically, simultaneous cules and erythematous papules, primarily confined 0 1996 Blackwell Science Ltd, Veterinary Dermatology, 7, 227-233 230 C.B. Wale et al. to the ventrum. A diffuse red-brown patch was The skin histopathology revealed findings similar located on the ventral neck and chest (Fig. 6). The to those seen in cats 1 and 2. Additionally, a minimal clinical similarity of the lesions to those observed in eosinophilic infiltrate within areas of mast cells and cat 2 was striking (Fig. 7). several discrete dermal lymphocytic nodules were Deep skin scrapings and dermatophyte cultures noted. A Giemsa stain highlighted the perivascular were negative. Dermatographism could not be and diffuse mast cells. A tentative diagnosis of feline elicited with vigorous stroking of the skin. A CBC urticaria pigmentosa also was made for cat 3. revealed neutrophilia (12 852 pL-'), eosinophilia Symptomatic treatment was initiated which in- (1020 pL-') and basophilia (1020 pL-I). All para- cluded oral hyroxyzine (2 mg kg-') three times daily meters in a serum biochemical profile and urinalysis and every-other-day bathing with a colloidal oat- were within established reference values. Feline meal-based shampoo. Ten days later, the macular leukaemia (ELISA) and feline immunodeficiency and papular lesions were partially resolved but viral tests were negative. Due to the presence of pruritus, although reduced, was still significant. eosinophilia and basophilia, an occult heartworm Prednisone therapy was initiated at 0.5 mg kg- ' antigen test was performed and was negative. In an given twice daily. Within 2 weeks, there was virtually attempt to evaluate the possibility of systemic in- complete resolution of the lesions and the pruritus volvement, a buffy coat examination, partial throm- was markedly diminished. Based upon beneficial boplastin time, prothrombin time, thoracic and response, the prednisone