Morphea-like lesion following topical endectocide application in a cat

Private practice, Dermatopet - Serviço de Dermatologia Veterinária, SHIS QI 28 cj 03 cs 02. 71670-230 Brasília, Brazil.
Veterinary Dermatology (Impact Factor: 1.73). 03/2012; 23(3):244-e50. DOI: 10.1111/j.1365-3164.2012.01039.x
Source: PubMed


Scleroderma is a rare chronic disease of connective tissues that may affect the skin in humans. Although still unclear, its aetiology may be related to drug reactions. To date, scleroderma has been reported in only a few dogs and one cat.
Localized (morphea-like) scleroderma was diagnosed in a 3-year-old intact male Persian cat that developed a nonpruritic, well-demarcated alopecic plaque a few days after topical application of a 'spot-on' solution containing praziquantel and emodepside. The lesion occurred at the site of application at the dorsal cervical region, and was characterized histologically by fibrosing dermatitis. There was no response to systemic treatment with pentoxifylline. Following topical therapy with minoxidil 5% for 30 days, hair regrowth occurred, and the lesion had completely disappeared after 60 days.
The relationship between the alopecic plaque and the topical application of the spot-on solution cannot be proved; however, according to the Naranjo scale, which estimates the probability of adverse drug reactions, this case could be classified as a 'possible' reaction to one of the components of the product. Sclerodermoid reactions have not been described as a cutaneous drug eruption in veterinary medicine, so this case may possibly represent the first such idiosyncratic reaction to one of the applied substances. Furthermore, to the best of the authors' knowledge, this is the second report of a morphea-like lesion in a cat.

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    ABSTRACT: A formulation containing 39.6% spinetoram resulted in a higher than anticipated number of reports of alopecia at the site of application in the first months following commercial product launch. To determine the cause of the alopecia using histopathology, including assessment for inflammation, follicular findings of physical trauma (plucking/pulling behaviour) and changes in follicular cycling. Twenty-four flea-free, male and female adult domestic short hair cats within a private research colony. Cats were treated with a single application of 39.6% spinetoram on day 0; personnel were not blinded. Observations of the skin and hair coat began immediately and were repeated at 30 min and 1, 2, 3, 4, 6, 8 and 12 h post-application and then on subsequent days at the same time as initial dosing and at 2, 4, 6, 8 and 12 h after that time, until day 5. If hair thinning or loss was observed, a skin biopsy sample was collected. Two cats not exhibiting abnormalities were biopsied on day 6. Thirty-eight per cent of cats (nine of 24) developed hair thinning and alopecia of sufficient severity within 78 h post-application of the product to warrant skin biopsy. Abnormalities in the skin were limited to the application site and were consistent with physical trauma (pulling or plucking) to the hair. Microscopic changes in the hair follicles of affected cats were consistent with self-induced trauma or barbering behaviour. All changes were reversible and paralleled findings associated with well-established, topical flea control products.
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    Full-text · Article · Jan 2014 · Acta Scientiae Veterinari
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    ABSTRACT: Background: Localized Scleroderma (morphea-like) is a rare disease in dogs and extremely rare in cats and it is an uncommon chronic connective tissue disease. There are only two reported cases of cats, dating from 1998 and 2012 and the cause is unknown. The clinical progression of the disease is unpredictable, but usually features moderate and self-limiting course. In the previously reported cases of cats, there was a clinical cure. The objective of this case report is to describe a case of Localized Scleroderma (morphea-like) in a cat that had historical and clinical progression of the disease in a distinct way from the two previously reported cases mentioned. Case: A 4 years old male cat, neutered, which belongs to the Persian breed, was presented with a history of chronic pruritus and alopecic lesions, without involving other organs. The lesions appeared with no history of trauma neither medications applied. Several treatments have been performed, but the only response found was a clinical improvement of pruritus. The presence of bruises and sores on the skin has never been observed, even before any treatment. Three lesions were observed in a specific clinical examination and they were all with the same pattern: the lesions were circular, irregular, alopecic, with peripheral halo slightly hyperemic and raised, and the lesion center with smooth, thin, opaque white skin and pigmented areas. The patient was treated with antibiotics and topical moisturizing lotion on the lesions, without satisfactory response. All differential diagnoses were discarded using additional tests and therapeutic trials. Collection of skin lesion fragments for histopathological evaluation was performed. It was concluded that the skin area showed no appendages accompanied with proliferation of dermal collagen tissue. As the lesions described in the clinical history appeared without reports of previous trauma or other local skin alteration, the histopathological pattern observed was compatible with localized scleroderma (morphea-like). It was instituted pentoxifylline therapy, in order to stimulate hair growth. After 30 days of treatment with pentoxifylline, the lesions remained unchanged. Discussion: The clinical features reported in cases of morphea include white or yellowish well-demarcated, alopecic, dry, firm and smooth glossy surface sclerotic plaques. As the cause of pruritus has not been established, a possibility to be considered is that the pruritus may be secondary to the skin lesion. The histopathological appraisal showed dermal collagen proliferation without pathological changes, compatible with morphea. As was not observed by the owner, sores and abrasions on the skin prior to the appearance of lesions, and as the follow-up period, the patient had no pruritus, it was not possible to identify the causative agent of this and could not differentiate whether the pruritus is primary or secondary to the skin sclerosis. The present case deals with localized scleroderma (morphea-like) itself, due to spontaneous appearance of lesions in a cat, without evidence of previous skins reactions (pharmacodermias or injuries caused by pruritus) to justify the establishment of scarring alopecias, proven diagnostic by histopathological appraisal of the affected skin, therefore, differentiating from scarring alopecia, the main differential diagnosis of morphea. There was no clinical resolution of the case to date. This case, unlike the cases previous described, showed no clinical resolution neither spontaneous remission after medical treatment.
    Full-text · Article · Jan 2014