Dermatophytosis in cats: A comprehensive study on diagnostic methods and their accuracy.

Background: Dermatophytosis is a contagious fungal infection that affects mainly cats. It poses significant challenges in veterinary medicine due to its zoonotic potential and impact on animal and public health. Rapid and reliable diagnosis is crucial for preventing the spread of the disease, guiding treatment decisions, and monitoring disease control efforts. Although there are several studies on diagnostic methods in feline dermatophytosis, the comparison between them from the same sample lacks data. The absence of a universally accepted gold standard diagnostic method highlights the need for a multifaceted approach to diagnosing feline dermatophytosis. Aim: This study aims to assess the accuracy and efficacy of different diagnostic techniques comprehensively. Methods: For this, 48 samples of cats were analyzed by dermoscopy, direct hair examination, fungal culture using various media (Mycosel, Sabouraud, and Dermatophyte Test Medium), and polymerase chain reaction (PCR). Results: Direct examination and dermoscopy yielded unsatisfactory results. Mycosel and Sabouraud were suboptimal. DTM demonstrated superior selectivity, making it the most reliable among traditional methods. PCR was the top performer, exhibiting singular sensitivity, specificity, and accuracy. Conclusion: The study suggests that PCR may be the preferred choice for diagnosing feline dermatophytosis in clinical practice, especially when rapid and accurate results are essential.

Proliferative, lymphocytic, infundibular mural folliculitis and dermatitis with prominent follicular apoptosis and parakeratotic casts in a Labrador retriever: Clinical, histopathological and dermoscopic features and co-morbidities.

Proliferative, lymphocytic, infundibular mural folliculitis and dermatitis have been reported in six female Labrador retrievers from North America. This is the first report of the disease outside North America, describing the clinical and histopathological diagnosis and dermoscopic aspect of the verrucous plaques, treatment and co-morbidities in a female Labrador retriever dog.

La folliculite et la dermatite murale infundibulaire proliférative, lymphocytaire ont été rapportées chez six Labrador retrievers femelles d'Amérique du Nord. Il s'agit du premier rapport de cette affection en dehors de l'Amérique du Nord, décrivant le diagnostic clinique et histopathologique, l'aspect dermatoscopique des plaques verruqueuses, le traitement et les comorbidités chez une femelle Labrador retriever.

A foliculite e dermatite mural linfocítica infundibular proliferativa tem sido relatada em seis cadelas Labrador retriever da América do Norte. Este é o primeiro relato da doença fora da América do Norte, descrevendo o diagnóstico clínico e histopatológico e o aspecto dermoscópico de placas verrucosas, tratamento de comorbidades em uma cadela Labrador retriever.

Se ha publicado la descripción de una foliculitis y dermatitis mural infundibular, linfocítica y proliferativa en seis hembras de Labrador Retriever de América del Norte. Este es el primer informe de la enfermedad fuera de América del Norte, que describe el diagnóstico clínico e histopatológico y el aspecto dermatoscópico de las placas verrugosas, el tratamiento y las comorbilidades en una perra Labrador Retriever.

Dermoscopic features of benign sebaceous proliferations in dogs: Description, assessment and inter-observer agreement.

BACKGROUND: Dermoscopy is a useful, noninvasive technique also used to assess sebaceous lesions in humans. Sebaceous hyperplasia, sebaceous adenoma and sebaceous epithelioma are common cutaneous lesions in dogs; however, their dermoscopic features have not been investigated. HYPOTHESIS/OBJECTIVES: The objectives of this study are to describe the dermoscopic features of canine sebaceous lesions and to assess the interobserver agreement on dermoscopic parameters. ANIMALS: Thirty-four lesions excised from 17 client-owned dogs, histologically confirmed as sebaceous proliferations, were included in this study. MATERIALS AND METHODS: Sebaceous lesions were evaluated in vivo at ×10 magnification with a handheld dermoscope. Each dermoscopic image was assessed independently by two ECVD board-certified veterinary referral clinicians and an ECVD resident. RESULTS: Thirty sebaceous hyperplasias, two sebaceous adenomas and two sebaceous epitheliomas were included. Dermoscopically, most lesions (91%) had single or multiple, well-defined, white-yellowish structures composed of grouped ovoid areas (clods). Irregular linear and, less commonly, arborising vessels were detected at the periphery of the yellow lobular-like structures in 93% of sebaceous hyperplasias and in 50% of neoplastic lesions. Erosions were seen in 6% of sebaceous hyperplasias and 50% of neoplastic lesions. Good interobserver agreement was found for white/yellowish clods (k = 0.75), yellow scales (k = 0.83), brown/grey dots (k = 0.80), erosions (k = 0.82) and red/brownish scales/crusts (k = 0.75). There was moderate agreement for fissures (k = 0.48) and vascular pattern (k = 0.51-0.53). CONCLUSIONS AND CLINICAL RELEVANCE: Dermoscopy represents a useful technique to assess sebaceous gland proliferations in dogs, as it is in humans.

The use of dermoscopy to support the diagnosis of sarcoptic mange in two dogs.

Two unrelated adult dogs presenting with chronic pruritic dermatitis were diagnosed with sarcoptic mange through the in vivo dermoscopic visualisation of Sarcoptes scabiei mites. The species of mite was confirmed via microscopy of superficial skin scrapings taken from lesional skin. Dermoscopy offers rapid point-of-care, noninvasive screening for dogs with sarcoptic mange.

Deux chiens adultes non apparentés présentant une dermatite prurigineuse chronique ont été diagnostiqués avec une gale sarcoptique par la visualisation dermoscopique in vivo d'acariens Sarcoptes scabiei. L'espèce d'acarien a été confirmée par microscopie de raclages cutanés superficiels prélevés sur la peau lésionnelle. La dermoscopie offre un dépistage rapide et non invasif au chevet du patient pour les chiens atteints de gale sarcoptique.

Dois cães adultos apresentando dermatite pruriginosa crônica foram diagnosticados com sarna sarcóptica através da visualização dermatoscópica in vivo dos ácaros Sarcoptes scabiei. A espécie de ácaro foi confirmada por avaliação microscópica de raspados cutâneos superficiais coletados de pele lesional. A dermatoscopia é um método diagnóstico que oferece triagem ambulatorial rápida e não invasiva para cães com sarna sarcóptica.

Dos perros adultos no relacionados que presentaban dermatitis pruriginosa crónica fueron diagnosticados con sarna sarcóptica a través de la visualización dermatoscópica in vivo de los ácaros Sarcoptes scabiei. La especie de ácaro se confirmó mediante microscopía de raspados cutáneos superficiales tomados de la piel lesionada. La dermatoscopia ofrece una detección rápida y no invasiva en el punto de atención primaria para perros con sarna sarcóptica.

Evaluation of skin erythema severity by dermatoscopy in dogs with atopic dermatitis.

BACKGROUND: To estimate the extent and severity of atopic dermatitis (AD)-related skin lesions, clinical trials enrolling dogs with AD often use categorical scales such as the Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04) and Canine Atopic Dermatitis Lesion Index (CADLI). Despite recent progress in the standardization of these AD-grading scales, the evaluation of the severity of skin lesions (including erythema) remains subjective. OBJECTIVES: To validate an optical set-up with a smartphone and a dermatoscope for the objective estimation of skin erythema severity in atopic dogs. ANIMALS: Forty-three dogs with AD. METHODS AND MATERIALS: An erythema index (EI) was calculated from calibrated skin images and compared to the dermatologist's erythema severity estimate using the erythema grading scale used in the CADESI-04, as well as an ad hoc Visual Analog Scale (VAS) with a continuous palette of red shades. RESULTS: We found a strong correlation based on the Spearman rank correlation coefficient between all erythema valuations: CADESI-04 and VAS: 0.93 [95% CI: (0.85, 0.96)]; CADESI-04 and EI: 0.85 (0.72, 0.92); VAS and EI: 0.82 (0.67, 0.91). There was a good agreement between the objective EI and CADESI-04-based estimates because 71% of samples were classified in the same erythema severity category. When comparing the EI and the VAS, the standard deviation of misestimates was 12% (maximum 100%). CONCLUSIONS AND CLINICAL RELEVANCE: The proposed optical set-up has the potential to make erythema severity estimation objective, thus leading to more reliable AD severity scales for the use in experimental canine AD models or in clinical trials enrolling atopic dogs.

Acral congenital superficial dermal lymphatic malformations in two unrelated cats: clinicopathological, dermoscopic and ultrastructural findings.

BACKGROUND: Cutaneous vascular malformations (CVM) represent a spectrum of human diseases identified at birth or in paediatric patients and classified according to the type of vessel affected. Confusing classification in human medicine has led to misdiagnoses and frequent nomenclature revision. Cutaneous lymphatic malformations (CLM) are reported sporadically in humans. OBJECTIVE: To describe the clinicopathological findings of superficial dermal cutaneous lymphatic malformations (SDCLM) in two cats. ANIMALS: Two unrelated adult domestic short hair cats. METHODS: The two cats were evaluated clinically and with a dermoscope for recurrent swelling and presence of vesicles oozing serosanguineous fluid affecting the right and left hind foot, respectively, since birth. Skin biopsy specimens were collected for histopathological and immunohistochemical evaluation and electron microscopy. RESULTS: A CVM was suspected based on the age of onset, clinical signs, results of diagnostic imaging and histopathological findings. Dermoscopy was used to describe the alterations of the skin surface. The involvement of the lymphatic vessels was confirmed using immunohistochemical findings and electron microscopy. CONCLUSION AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first description of the clinical, dermoscopic, histopathological and ultrastructural characteristics of SDCLM in cats resembling the human counterpart. SDCLMs are rare conditions and appropriate histopathological and immunohistochemical confirmation is required to avoid misdiagnosis and mistreatment.

Evaluation of hair follicle parameters using TrichoScale Pro© in healthy dogs: a pilot study.

BACKGROUND: Trichoscopy, in combination with image analysis software, is a readily available, efficient diagnostic tool for assessing hair follicle parameters of people in vivo. Systems designed for use in human dermatology must be evaluated and validated with animal skin/hair before they can be used for veterinary applications. OBJECTIVES: To evaluate the use of a commercial software package for image analysis of canine hair follicles and to define hair follicle parameters. ANIMALS: Thirteen client-owned healthy dogs. METHODS: Trichoscopic images at x20 magnification were obtained from three shaved body sites (left dorsal head, left thorax, left flank) over a five day period, then analyzed by the software. RESULTS: The image analysis software was able to identify microscopic changes in hair length on a daily basis, calculating a mean hair growth rate of 0.065 mm/day. Each of the three body sites had consistent hair growth rates across all days. Anagen and telogen percentages were consistent at each body site by Day 2 (48 h post-clipping). Data for mean hair thickness, and primary and secondary hair percentages also are reported. CONCLUSIONS: Although it provides less useful data for canine hair coats than for human scalp hair, the system evaluated provides an easy, noninvasive, rapid means for assessing several important canine hair follicle parameters: daily hair growth rates, anagen and telogen percentages, primary and secondary hair percentages, and mean hair thickness. This diagnostic tool could serve to establish breed-specific hair coat standards, evaluating hair follicle changes in various canine alopecic conditions and monitoring coat-promoting treatments in dogs.

Dermoscopic analysis of the skin of healthy warmblood horses: a descriptive study of 34 cases in Italy.

BACKGROUND: Dermoscopy is a diagnostic tool that has been introduced into small animal dermatology for the evaluation of hair and the skin surface. To the best of the authors' knowledge, the use of this technique on horses and the dermoscopic appearance of equine hair and skin have yet to be reported. HYPOTHESIS/OBJECTIVES: To assess the feasibility of dermoscopy, and to describe hair and skin surface features of healthy warmblood horses. ANIMALS: Thirty four client-owned, healthy adult horses. METHODS: Six body regions (head, neck, dorsal thorax, ventral thorax, croup and mane) were examined with a smartphone-attached, hand-held polarized light dermoscope at 20-fold magnification. Smartphone-collected images were evaluated to determine the overall hair density, large and thin primary hair densities and diameters, and skin surface characteristics. Software was used to measure large and thin primary hair shaft thickness. Comparisons between body regions, breeds and sexes were made. RESULTS: Dermoscopic examination of the equine skin surface was feasible and easy to perform. At 20-fold magnification thick, straight hair shafts emerging from single follicular openings were observed. In between these, thinner straight hair shafts were present in all evaluated regions. Hair shafts of the head and the mane were significantly thicker but less dense compared to other regions. Skin pigmentation and variable perifollicular discolouration were present. CONCLUSIONS: Dermoscopy may represent a valuable technique for the dermatological examination of the equine patient.

Comparing dermoscopy and histological examination of normal equine skin.

BACKGROUND: Dermoscopy is a noninvasive diagnostic technique that allows visualization of structures of the superficial dermis not visible with the naked eye. HYPOTHESIS/OBJECTIVES: To assess the usefulness and applicability of dermoscopy for evaluation of healthy equine skin. ANIMALS: Twelve healthy horses from a research herd. METHODS: Five regions (cheek, lateral neck, dorsum, flank and abdomen) were examined with contact dermoscopy using both nonpolarized and polarized light at both 17-fold and 24-fold magnification. These findings were compared to histological features of skin biopsies cut both longitudinally and transversely. RESULTS: Using a hand-held dermatoscope with nonpolarized light, epidermal ridges were observed. Using polarized light, follicular openings and distinctly separate epidermal openings of sweat gland ducts were observed in some but not all individuals. Similarities were noted between histological and dermoscopic results. CONCLUSIONS: Although not ideal for visualizing many structures in the superficial dermis of healthy equine skin, dermoscopy allowed visualization of epidermal ridges, hair shafts in the infundibular portion of the hair follicles and sweat gland duct openings. Dermoscopy could potentially be useful in the evaluation of diseases affecting the sweat glands, epidermis and hair shaft.

The usefulness of dermoscopy in canine pattern alopecia: a descriptive study.

BACKGROUND: Dermoscopic studies evaluating noninflammatory, nonpruritic progressive alopecia attributable to pattern alopecia are currently unavailable. HYPOTHESIS/OBJECTIVES: To evaluate the dermoscopic features observed in healthy skin of short coated dogs and compare these findings with those observed in dogs affected by pattern alopecia diagnosed by clinical and dermatopathological examination. ANIMALS: Thirty male and female, healthy, breed matched, young adult, short coated dogs (controls) and 30 male and female, young adult, short coated dogs affected by pattern alopecia. METHODS: Dermoscopy was performed with a Fotofinder II videodermoscope equipped with software that allowed the measurement of structures visualized in magnified images (20×-40×-70×). Skin biopsy samples were obtained from the thorax and evaluated dermoscopically for dermoscopic-histological correlation in affected dogs. RESULTS: Dermoscopic findings in canine pattern alopecia were hair shaft thinning, circle hairs and follicular keratin plugs; in the affected sun exposed areas there was a honeycomb-like pattern of pigmentation. Arborizing red lines reflecting vascularization were classified as a nonspecific finding because they were also common in healthy dogs. Dermoscopic features correlated with histology for selected hair follicle abnormalities. CONCLUSIONS AND CLINICAL IMPORTANCE: Although canine pattern alopecia is a visually striking disease, this study supports the value of dermoscopy for clinical examination and also opens promising perspectives for the identification of diagnostic dermoscopic patterns that may be useful for other skin disorders.

Evaluation of dermoscopy in the diagnosis of naturally occurring dermatophytosis in cats.

BACKGROUND: A rapid, accurate screening test for dermatophytosis in cats is desirable in clinical and shelter medicine. In human dermatology, dermoscopy is used to identify dermatophyte-infected hairs by their characteristic comma hair appearance. Similar "comma-like" hairs have been observed in infected cats. HYPOTHESIS/OBJECTIVES: The purpose of this study was to evaluate the usefulness of dermoscopy for the diagnosis of naturally occurring dermatophytosis compared to fungal culture. ANIMALS: A total of 67 cats were enrolled. METHODS: This was a descriptive field study. All cats were evaluated by dermoscopy and fungal culture. Dermoscopy was performed with a hand held nonpolarized light dermoscope. RESULTS: Three dermatophyte pathogens were isolated via fungal cultures in 36 cats: Microsporum canis (n = 31), Microsporum gypseum (n = 3) and Trichophyton mentagrophytes (n = 2). Dermoscopy was positive in 21 of 36 cats with culture-confirmed dermatophytosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Dermoscopy may be a useful point-of care-test to identify infected hairs to sample for dermatophyte cultures, but a definitive diagnosis for dermatophytosis should be based on clinical signs and the results of multiple diagnostic tests.

Dermoscopic features in 12 cats with dermatophytosis and in 12 cats with self-induced alopecia due to other causes: an observational descriptive study.

BACKGROUND: Dermoscopy is a noninvasive technique allowing rapid magnified in vivo observation of the skin and structures that lie beneath the skin surface. Various congenital and acquired hair shaft abnormalities may also be evaluated by dermoscopy. Additionally, characteristic features of Microsporum canis-induced tinea capitis and trichotillomania in humans have been reported. OBJECTIVES: To describe the dermoscopic findings observed in cats with patchy alopecia due to M. canis infection and in cats with self-inflicted hair loss. ANIMALS: Twenty-four client-owned cats presented at a veterinary referral practice. METHODS: Dermoscopy was performed with a hand-held nonpolarized light dermoscope at 10-fold magnification. The glass plate of the dermoscope was applied gently to the lesions and no sedation was required. RESULTS: Twelve cats were diagnosed with dermatophytosis and 12 with self-induced alopecia due to other causes. At 10-fold magnification, the most characteristic findings observed in circumscribed lesions of cats with dermatophytosis were opaque, slightly curved, broken hairs of a homogeneous thickness (comma-like structures) and a variable amount of brown-to-yellow greasy scales. In cats with self-induced alopecia, multiple hairs with a normal shaft cleanly broken at different lengths, short tufts of hairs broken at an equal level and hook-like and coiled hairs were observed. CONCLUSIONS AND CLINICAL IMPORTANCE: This observational descriptive study suggests that dermoscopy may represent a helpful noninvasive in vivo technique in the differential diagnosis of patchy alopecia in cats.

Dermoscopic evaluation of skin in healthy cats.

BACKGROUND: Dermoscopy is a diagnostic tool that can reveal morphological structures not visible upon clinical examination. HYPOTHESIS/OBJECTIVES: To assess the usefulness and applicability of dermoscopy for the examination of healthy cat skin. ANIMALS: Twenty-one domestic short-haired cats from a feline rescue association. METHODS: Four regions (head, dorsal neck, sacral and abdominal regions) were examined with both a contact hand-held nonpolarized light dermoscope at 10-fold magnification and a videodermoscope at 70-fold magnification. Findings were assessed using histological analysis of skin samples cut both longitudinally and transversely, set as the gold standard. RESULTS: With a hand-held dermoscope at 10-fold magnification, thick, straight primary hairs surrounded by multiple secondary hairs were observed. With a videodermoscope at 70-fold magnification, hair shaft thickness was measured and the follicular openings and arrangement of vessels were clearly observed. Correspondence was observed between dermoscopic and histological results. CONCLUSIONS AND CLINICAL IMPORTANCE: Dermoscopy represents a valid noninvasive and reproducible technique that could be helpful in clinical examination.