Protothecosis and chlorellosis in sheep and goats: a review.

Protothecosis and chlorellosis are sporadic algal diseases that can affect small ruminants. In goats, protothecosis is primarily associated with lesions in the nose and should be included in the differential diagnosis of causes of rhinitis. In sheep, chlorellosis causes typical green granulomatous lesions in various organs. Outbreaks of chlorellosis have been reported in sheep consuming stagnant water, grass from sewage-contaminated areas, and pastures watered by irrigation canals or by effluents from poultry-processing plants. Prototheca and Chlorella are widespread in the environment, and environmental and climatic changes promoted by anthropogenic activities may have increased the frequency of diseases produced by them. The diagnosis of these diseases must be based on gross, microscopic, and ultrastructural lesions, coupled with detection of the agent by immunohistochemical-, molecular-, and/or culture-based methods.

[Disseminated protothecosis with ulcerative granulomatous colitis in a Rhodesian Ridgeback from Germany]. / Ulzerative granulomatöse Kolitis durch Prototheca spp. bei einem Rhodesian Ridgeback in Deutschland.

A 10-month-old male Rhodesian Ridgeback was presented to the Clinic of Small Animal Medicine, LMU, Germany, with a 6-month history of chronic diarrhea and hematochezia. The dog lived in Germany and had never traveled abroad. Complete blood count and serum biochemistry performed by the referring veterinarian revealed neutrophilia, hyperkalemia, and hyponatremia, with a basal cortisol of 4.3 µg/dl, which excluded hypoadrenocorticism. Since antibiotic treatment had not resulted in any improvement, a 2 week course of prednisolone administration had been initiated, leading to a marked deterioration of intestinal signs and a significant weight loss of 6 kg. At the time of referral, the patient was markedly emaciated, dehydrated, hypovolemic and had a rectal temperature of 39.6 °C. Abdominal ultrasound showed a thickened and irregular colonic wall. On colonoscopy, an irregular colonic mucosa with ulcerations was observed. Histopathologic examination revealed an ulcerative granulomatous colitis, and on Periodic acid-Schiff reaction (PAS) numerous organisms consistent with Prototheca spp. were identified. Prototheca zopfii infection was confirmed by culture and MALDI-TOF MS. In order to test for an underlying immunodeficiency, immunoglobulin levels in serum were determined. IgM was decreased, while IgG and IgA levels were within the reference interval. Due to deterioration of general condition, grave prognosis and costs of a treatment trial, the patient was euthanized one week later, and necropsy was performed. Prototheca spp. were detected on histopathologic examination in the lymphnodes, however not in the eyes or the central nervous system. Protothecosis should be considered an differential diagnosis in dogs with chronic diarrhea and ulcerative granulomatous colitis even in dogs living in Germany. Histopathologic examination of colonic biopsies with special stains such as PAS is recommended in every dog with signs of chronic large bowel disease in order to avoid missing this rare infectious disease.

Parengyodontium album Isolated from Cutaneous Lesions of a Pacific White-Sided Dolphin (Lagenorhynchus obliquidens) During Treatment for Paracoccidioidomycosis Ceti.

The prominence of seafood in Japan motivates close monitoring of its seas and marine lives for potentially pathogenic fungi. During the treatments of the male Pacific white-sided dolphin (Lagenorhynchus obliquidens) for paracoccidioidomycosis ceti (PCM-C), 5 white and floccose colonies showing identical genotype and morphological characteristics were isolated from two skin biopsy samples of cutaneous granulomatous lesions in 2018. The isolates were identified as Parengyodontium album known as one of fungal species having abilities to produce industrially important proteases, and to become a causative agent for emerging mycosis based on morphological and molecular biological characteristics. These lesions consisted of non-malignant pearl-like structures of hyperplastic keratinocytes. Interestingly, although the isolates could grow at 35 °C, their DNA sequences were phylogenetically located in a cluster consisting of environmental and clinical isolates lacking the ability to grow at 35 °C, based on previous reports. The opportunistic infection we observed in the dolphin might be caused by immune disorder due to PCM-C. Notably, although P. album is recognized as non-harmful, and has significant industrial importance and antitumor activity, it has potential to cause not only superficial but also systemic infection, and presents difficulties in treatment because of its high resistance to antifungal compounds.

Cytologic, histologic, microbiologic, and electron microscopic characterization of a canine Prototheca wickerhamii infection.

An adult dog was presented for chronic cough and a recent development of ulcerated, erythematous nares with nasal discharge. Cytology of enlarged peripheral lymph nodes revealed many intracellular and extracellular organisms. These round or rarely oval organisms measured approximately 5-9 µm in diameter and frequently contained several globular structures, ranging from deeply basophilic to magenta. A thin, clear halo was present. Smaller 1-2 µm, magenta forms were also observed. Fungal culture yielded small, wet, raised, irregularly shaped, white to pale tan colonies. Microbiologic staining of cultured material revealed features suggestive of algae. Histopathology of the lymph nodes revealed marked granulomatous inflammation with intralesional algal organisms suggestive of Prototheca. Electron microscopic findings were also consistent with protothecosis. Polymerase chain reaction, followed by direct DNA sequencing, identified the organism as Prototheca wickerhamii. A brief literature review discussing protothecosis in veterinary medicine is included.

In vitro algicidal effect of polypyrrole on Prototheca species isolates from bovine mastitisAlgicidal activity of polypyrrole on Prototheca spp.

Algae of the genus Prototheca are microorganisms involved in the occurrence of diseases in humans and animals. In bovine species, Prototheca spp. cause environmental mastitis, productive losses in dairy herds, mainly leading to the discard of infected cows. Currently, there are no effective anti-Prototheca spp. drugs to combat this infection. Thus, the search for an efficacious therapy for Prototheca spp. infections have become essential. Highly soluble polypyrrole (Ppy) is a molecule with known antimicrobial activity. This study aimed to characterize Prototheca spp. isolates from bovine mastitis as well as to evaluate the susceptibility profile and to verify the morphological alterations on Prototheca spp. isolates treated with Ppy. In this research, 36 Brazilian isolates of Prototheca spp. were characterized by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) assay for the mitochondrial cytB gene. Additionally, Ppy algicidal activity against these isolates of Prototheca spp. was assessed by minimal microbicidal concentration method in microplates. Further, scanning electron microscopy (SEM) was performed in order to verify the morphological alterations on Prototheca spp. isolates in response to Ppy. The isolates were characterized as belonging to Prototheca zopfii genotype 2 (35/36) and Prototheca blaschkeae (1/36). Ppy had an algicidal effect on all isolates tested at concentrations ranging from 15.625 µg ml-1 to 62.5 µg ml-1. SEM showed changes on planktonic and sessile P. zopfii, including a decrease of the number of cells with the presence of an amorphous substance involving the cells. The algicidal activity of Ppy suggests the therapeutic potential of this molecule in the prevention and treatment of Prototheca spp. in bovine mastitis.

Emergence of Fungal-Like Organisms: Prototheca.

The genus Prototheca consists of achlorophyllic algae that are ubiquitous in the environment and animal intestines. However, this organism has forfeited its photosynthetic ability and switched to parasitism. In 1894, Krüger described two microorganisms isolated in Germany from mucous flux of Tilia and Ulmus spp., namely Prototheca moriformis and P. zopfii. Based on their yeast-like colony morphology, Krüger classified these organisms as fungi. The genus is now included within the class Trebouxiophyceae, order Chlorellales, and family Chlorellaceae. Historically, protothecosis and infections caused by green algae have been studied in the field of medical mycology. Prototheca spp. have been found to colonize human skin, fingernails, the respiratory tract, and digestive system. Although human infection by Prototheca is considered rare, an increase in infections has been noted among immunosuppressed patients, those on corticosteroid treatment, or both. Moreover, the first human outbreak of protothecal algaemia and sepsis was recently reported in a tertiary care chemotherapy oncology unit in 2018. Prototheca is also a causative pathogen of bovine disease. Prototheca zopfii and P. blaschkeae are associated with bovine mastitis, which causes a reduction in milk production and secretion of thin, watery milk containing white flakes. Economic losses are incurred either directly via reduced milk production and premature culling of affected animals or indirectly as a result of treatment and veterinary care expenses. Thus, knowledge of this fungal-like pathogen is essential in human and veterinary medicine. In this mini-review, I briefly introduce human and animal protothecoses.

[Cutaneous infection with Orthopoxvirus bovis in a German Spaniel]. / Kutane Infektion mit Orthopoxvirus bovis bei einem Wachtelhund.

A 4-year-old female German Spaniel was presented with anorexia. Clinically, the dog showed papular to ulcerative lesions on the nasal planum and on the tongue. Hematological, bacteriological and mycological examinations did not contribute any evidence for the etiology of the lesions. Histopathological examination of skin biopsies revealed a proliferative dermatitis and folliculitis with hydropic degeneration of keratinocytes and cytoplasmatic inclusion bodies. Cowpox virus antigen was detected by immunohistochemistry, and electron microscopy showed pox virus particles in the cytoplasm of the epithelial cells. DNA of Orthopoxvirus bovis was identified by polymerase chain reaction. Consequently, in dogs with papular to ulcerative lesions in the face or on the tongue, infection with cowpoxvirus should be considered as an etiological differential diagnosis. Infected dogs represent a potential risk of infection for humans and other animals with close contact.

Donkey dermatology.

Donkeys (Equus asinus) are a species used throughout the world primarily as beasts of burden, but occasionally for other functions, as a meat source or as pets. Although closely related to other equids, they have some unique features of their own with regard to dermatologic disease. This article highlights some of the various dermatoses seen or reported in donkeys, as well as some comparisons with horses when prevalence, presentation, or treatment may differ.

Frequency of presentation of bovine cutaneous pythiosis (Pythium insidiosum) in three cattle farms in Cordoba, Colombia / Frecuencia de presentación de Pythiosis Cutánea Bovina (Pythiuminsidiosum) en tres explotaciones ganaderas de Córdoba, Colombia / Freqüência de apresentação da Pitiose Cutânea Bovina (Pythiuminsidiosum) em 3 fazendas em Córdoba, Colômbia

The skin pythiosis is a chronic granulomatous, often pruriginous, rapidly progressive illness, caused by Pythium insidiosum. The objective of this study was to determine the frequency of occurrence of bovine cutaneous pythiosis (Pythium insidiosum) in three farms in the department of Cordoba, Colombia. A prospective study in animals was performed, for convenience, between May and August 2011. 72 cattle with granulomatous skin lesions compatible with Pythiosis were evaluated clinical, epidemiological and histopathologically, from 187 cows belonging to three farms located in flood zones in the department of Cordoba, Colombia. The frequency of occurrence of bovine cutaneous Pythiosis in 3 cattle farms in Córdoba department, Colombia was 38,5%. It was concluded that clinical and epidemiological manifestations, macroscopic characteristics of the skin lesions and pathological findings, reported a median pythiosis presence of bovine dermal three farms located in flood zones of the department of Cordoba, Colombia.

La Pythiosis cutánea es una enfermedad crónica, granulomatosa, a menudo pruriginosa y rápidamente progresiva, causada por el Pythium insidiosum. El objetivo del presente estudio fue determinar la frecuencia de presentación de pythiosis cutánea bovina en tres explotaciones ganaderas del departamento de Córdoba, Colombia. Se realizó un estudio descriptivo prospectivo en animales a conveniencia, entre los meses de mayo y agosto de 2011. Fueron evaluados clínica, epidemiológica e histopatológicamente 72 bovinos con lesiones cutáneas granulomatosas compatibles con Pythiosis, a partir de 187 bovinos pertenecientes a tres explotaciones ganaderas ubicadas en zonas inundables del departamento de Córdoba, Colombia. La frecuencia de la enfermedad fue de 38.5%. Se concluye que por las manifestaciones clínico-epidemiológicas, las características macroscópicas de las lesiones cutáneas y los hallazgos histopatológicos, se informa una mediana presencia de pythiosis cutánea en bovinos de tres explotaciones ganaderas ubicadas en zonas inundables del departamento de Córdoba, Colombia.

A pitiose cutânea é uma doença granulomatosa crônica, muitas vezes pruriginosa e rapidamente progressiva, causada por Pythium insidiosum. O objetivo deste estudo foi determinar a freqüência de ocorrência de pitiose cutânea bovina (Pythium insidiosum) em três fazendas no departamento de Córdoba, Colômbia. Foi realizado um estudo prospectivo em animais a conveniência, entre Maio e Agosto de 2011. Foram avaliados clínica, epidemiológica e histopatologicamente 72 bovinos com lesões cutâneas granulomatosas compatíveis com pitiose, a partir de 187 bovinos pertencentes a 3 fazendas localizadas em zonas inundáveis, no departamento de Córdoba, Colômbia. A freqüência de ocorrência de pitiose cutânea bovina em 3 fazendas no departamento de Córdoba, Colômbia foi de 38,5%. Concluímos que as manifestações clínicas e epidemiológicas, características macroscópicas das lesões de pele e achados patológicos, relatou uma presença mediana de pitiose bovina cutânea em 3 fazendas localizadas em zonas inundáveis no departamento de Córdoba, na Colômbia.

Detection of six novel papillomavirus sequences within canine pigmented plaques.

In dogs, papillomaviruses are thought to cause oral and cutaneous papillomas and pigmented plaques. Eight canine papillomaviruses have been fully sequenced to date. Four of these canine papillomaviruses, including Canis familiaris papillomavirus (CPV)-3, CPV-4, CPV-5, and CPV-8, were amplified from pigmented plaques. Given the identification of several different canine papillomaviruses within pigmented plaques, it is likely that there are additional papillomavirus sequences that have not been previously identified. The aim of the present study was to amplify papillomavirus DNA from pigmented plaques and identify potentially novel papillomavirus sequences through nucleotide sequence analysis. Polymerase chain reaction was used to amplify DNA sequences of the papillomavirus L1 gene from 27 pigmented plaques. Identification of novel papillomavirus sequences was based on less than 90% shared DNA homology to any known papillomavirus. DNA from 10 different papillomaviruses was identified within the pigmented plaques, including 6 putative novel papillomavirus sequences. CPV-4 was detected within 41% (11/27) of the pigmented plaques, while CPV-5 was identified within 2 pigmented plaques and CPV-3 within a single pigmented plaque. A previously identified novel papillomavirus sequence was identified within 2 pigmented plaques. The remaining 11 pigmented plaques contained 6 papillomavirus DNA sequences that have not been previously reported. These putative novel PV sequences were most similar to the canine papillomaviruses that have been detected within canine pigmented plaques.

Condition-based use of antimicrobials in cats in Finland: results from two surveys.

Two surveys were carried out to investigate how antimicrobials are used in cats in Finland. Information was retrieved from 419 prescriptions and 311 questionnaire sheets concerning antimicrobial treatment for feline patients. Infected wounds, skin disorders and urinary tract infections were the most common reasons for antimicrobial treatment in cats. Compliance with prudent use guidelines was good. beta-Lactams such as amoxycillin and amoxycillin with clavulanic acid were frequently used. Fluoroquinolones were used judiciously. The median length of treatment was 10 days for most conditions. Diagnosis was mainly based on clinical signs, and bacteriological culture and sensitivity testing was rarely performed. This study provides basic descriptive information on how antimicrobials are used in cats and that could help when revising guidelines for the condition-based use of antimicrobials in animals.

Cutaneous sterile granulomas/pyogranulomas, leishmaniasis and mycobacterial infections.

Cutaneous "sterile" granulomas represent a group of uncommon skin disorders of unknown aetiopathogenesis. Many diseases are included in this group (for example, sterile granuloma/pyogranuloma syndrome and reactive histiocytosis). The definition of sterile is based on the exclusion of other possible aetiological agents (for example, microorganisms or foreign body). Many techniques are used to rule out a microbial aetiology including cytology, histology, immunohistochemistry and culture. However, some organisms are "fastidious" and difficult to culture or to identify with routine methods, and molecular studies are necessary. This is particularly true for mycobacteria (for example, canine leproid granuloma syndrome) and Leishmania. Recently, studies in human and veterinary medicine have proved the presence of microorganisms (mycobacteria and Leishmania) using a polymerase chain reaction technique in specimens previously diagnosed as sterile. Therefore, it is very important, with the development of new technologies, to use a multidisciplinary diagnostic approach to definitively rule out any microorganism before declaring a disease sterile.

Dermatite digital papilomatosa (DDP) - revisão da literatura / Papilomatous digital dermatitis: literature review

A presente revisão bibliográfica contém informações sobre a dermatite digital papilomatosa (DDP), dermatopatia podal infecciosa emergente, que acomete os bovinos leiteiros e causa inflamação com erosão, ulceração e proliferação da pele nas regiões do bulbo, espaço interdigital e na coroa do casco. Foram mundialmente descritos grandes prejuízos econômicos causados pela doença, porém, os índices específicos de incidência da DDP são desconhecidos em vários Estados do Brasil, devido à carência de informações sobre este assunto. O objetivo desta invertigação foi obter subsídios na literatura para auxiliar buiatras no reconhecimento, tratamento e prevenção desta enfermidade.

Topical tea tree oil effective in canine localised pruritic dermatitis--a multi-centre randomised double-blind controlled clinical trial in the veterinary practice.

Tea tree oil, a volatile oil, is well known for its broad antibacterial and antifungal activity. A standardised and stabilised 10% tea tree oil cream was tested against a commercial skin care cream (control cream) in the management of canine localised acute and chronic dermatitis. Fifty-seven dogs with clinical manifestations of mostly pruritic skin lesions or alterations, skin fold pyodermas and other forms of dermatitis, corroborated by predominantly positive fungal and bacterial skin isolates, were enrolled by seven practising veterinarians and randomly allocated to two study groups (28:29) and were treated twice daily with a blinded topical preparation. After 10 days of treatment, success rates of 71% for the tea tree oil cream and 41% for the control cream (over-all efficacy documented by the veterinary investigator) differed significantly (p = 0.04), favouring tea tree oil cream treatment. Accordingly on day 10, the tea tree oil cream caused significantly faster relief than the control cream (p = 0.04) for two common clinical dermatitis signs, pruritus (occurring in 84 % of dogs) and alopecia. Only one adverse event was reported in the tea tree oil group (suspected not to be causally related to the study drug) and none in the control cream group. The tested herbal cream appears to be a fast-acting safe alternative to conventional therapy for symptomatic treatment of canine localised dermatitis with pruritus.

Clinicopathologic findings associated with Lagenidium sp. infection in 6 dogs: initial description of an emerging oomycosis.

An oomycotic pathogen in the genus Lagenidium was isolated from tissues obtained from 6 dogs with progressive cutaneous disease. Initial clinical findings in 5 dogs included multifocal cutaneous lesions, subcutaneous lesions, or both associated with regional lymphadenopathy: the 6th dog initially was presented for evaluation of mandibular lymphadenopathy. Cutaneous lesions were ulcerated, exudative regions (often with necrosis and draining tracts) or multiple firm dermal or subcutaneous nodules. Two dogs subsequently developed hemoabdomen from great vessel rupture and died acutely. Four dogs were euthanized because of progression of subcutaneous lesions or lymphadenopathy. On postmortem examination, regional granulomatous lymphadenitis was found in all 6 dogs, great vessel invasion in 3 dogs, pulmonary lesions in 2 dogs. ureteral obstruction in 1 dog, mediastinal lymphadenitis in 1 dog, and hilar lymphadenitis with invasion of the distal esophagus and trachea in 1 dog. Histologically, lesions were similar to those associated with pythiosis and zygomycosis and were characterized by severe eosinophilic granulomatous inflammation (often with numerous large multinucleated giant cells) centered around broad (7-25 micro), infrequently septate hyphae. Immunoblot analysis of the serologic response of 4 dogs to a soluble mycelial extract of Lagenidium giganteum indicated that each dog's serum recognized at least 10 different antigens of L. giganteum. Culture of infected tissues yielded rapid growth of colorless to white submerged colonies. Microscopically, mature hyphae in culture were broad (25-40 micro), segmented, and occasionally branching and produced motile laterally biflagellate zoospores in water culture. This report is the 1st description of infection caused by an oomycete other than Pythium insidiosum in any mammalian species.

Severe persistent orf in young goats.

Orf (contagious ecthyma) is a viral disease of small and wild ruminants, humans, and less frequently other species. In sheep and goats, the disease is characterized by the formation of vesiculo-proliferative lesions in the skin of lips and nostril. Here, a form of generalized orf in 16 goat kids from 2 different locations in west Texas is described. The disease was characterized by multifocal, severe, proliferative dermatitis that persisted from about 2 months of age until the goat kids were euthanized 3 months later. All affected goats were Boer or Boer crosses under 1 year of age. The mean immunoglobulin concentration in sera of affected goats was elevated compared with healthy control goats. Severe to moderate lymphadenomegaly of the nodes draining the areas of the skin affected with orf lesions was present in all 16 goat kids. Suppurative arthritis, chronic fibrinous pneumonia, and premature thymic involution were found in 3, 5, and 7 of the goat kids, respectively. The skin lesions of 3 goat kids were infested with larvae of the opportunistic black garbage fly (Ophira sp.). The orf virus was identified in skin lesions by isolation in Marbin-Darby ovine kidney cells, electron microscopy, and amplification of viral DNA by polymerase chain reaction. The orf virus was not detected in peripheral blood or lymph node mononuclear cells of any of the goats. Cross-neutralization experiments showed that an ovine orf virus antiserum raised in sheep was more effective in neutralizing a sheep orf virus isolate than a caprine orf virus isolate. The clinical and epidemiological characteristics of these orf cases may be the result of susceptibility factors within some individuals of the Boer breed of goats.

Antagonistic activity of Aeromonas media strain A199 against Saprolegnia sp., an opportunistic pathogen of the eel, Anguilla australis Richardson.

A bacteriocin-like inhibitory substance (BLIS) produced by Aeromonas media strain A199 inhibited the growth of Saprolegnia sp. in vitro, an opportunistic pathogen isolated from affected eels, Anguilla australis (Richardson). The presence of BLIS in solid media inhibited the growth of the vegetative state of the aquatic mould as well as the germination of cysts. Uninhibited growth was, however, observed in the presence of inactive BLIS, suggesting that the in vitro antagonism derived from the BLIS of A199. In four independent in vivo tank observations of fish affected with saprolegniosis, the daily addition of A199 to tank water contributed to the subsequent swift recovery of affected hosts from invasion by this opportunistic pathogen.

Immunotherapy for treatment of multicentric cutaneous pythiosis in a dog.

A 4-year-old Labrador Retriever was referred for evaluation of 2 ulcerative nodular cutaneous lesions. One lesion was located on the medial aspect of the right carpus; the other was located on the medial aspect of the left tarsus. The dog had spent its entire life in the southeastern part of the United States and approximately half of its time outdoors with free access to a nearby lake. Histologic examination of full-thickness wedge biopsy specimens from both lesions revealed severe, multifocal, puruloeosinophilic to pyogranulomatous deep dermatitis with intralesional filamentous structures, fibroplasia, and neovascularization. Examination of sections stained with Gomori methenamine silver stain revealed a moderate number of wide, bulbous, irregularly septate, branching hyphae. Results of an immunodiffusion test and an ELISA for anti-Pythium insidiosum antibodies were positive. Amputation was eliminated as a treatment option because lesions involved 2 limbs. Long-term systemic antifungal treatment was also rejected because of the cost, lack of therapeutic effect in many cases, and potential for adverse effects. The dog was treated with 2 doses of an anti-P insidiosum vaccine administered 2 weeks apart. One month later, the lesions were nearly completely healed, and values obtained via the immunodiffusion test and ELISA had decreased. Results of the immunodiffusion test and ELISA were negative 1 year later, and the dog had not had any recurrences.

Cutaneous lesions.

Although not a substitute for histologic examination, lumps, bumps, and lesions of the skin and subcutis readily lend themselves to cytologic examination via FNB, fine-needle nonaspiration biopsy, imprinting, or scraping of lesions. These techniques are used to obtain cells that can be examined by a clinical pathologist or cytologist to provide a diagnosis, decide a course of therapy, or offer a prognosis. Although histologic and cytologic examinations do not always agree, many times there is excellent correlation between the two disciplines. There are few patients with cutaneous lesions that would not benefit from cytologic examination of their lesion.

Review cutaneous lesions of the canine scrotum.

Scrotal lesions are uncommon and often present a diagnostic challenge. In the veterinary literature there are no texts devoted to this subject. This study reviews and illustrates canine scrotal lesions following an aetiological layout with the aim of facilitating clinical identification and diagnosis. Infectious, immune-mediated, endocrinological and neoplastic conditions are the most commonly reported causes of scrotal lesions in the dog. They may affect the scrotum only or other parts of the body as well. The clinical presentation of the lesions, the presence of primary or secondary lesions and the presence of clinical signs of systemic disease may help in obtaining a diagnosis. In some cases further investigations are necessary to reach a definitive diagnosis. Histopathology aids in understanding pathological reactions of the scrotal skin but unfortunately this is not commonly carried out and few reports in the literature include histopathology. The list of conditions given in this review is not exhaustive and other, more rare, diseases may be encountered.