Sarcoptic Mange in a Tasmanian Devil (Sarcophilus harrisii) and Bennett's Wallaby (Notamacropus rufogriseus).

Sarcoptes scabiei mites and skin lesions consistent with severe sarcoptic mange were identified in a Tasmanian devil (Sarcophilus harrisii) and Bennett's wallaby (Notamacropus rufogriseus) from Tasmania, Australia. The devil and wallaby both had severe hyperkeratotic skin lesions. All stages of mite development were identified in the devil, suggesting parasite reproduction on the host. The devil was also affected by devil facial tumor disease and several other parasites. This expands the global host range of species susceptible to this panzootic mange disease.

Prevalence and clinico-pathology of PSOROPTIC mange in buffaloes of the Amazon region.

Scabies is an important skin disease in several species of domestic and wild animals; however, few reports in Brazil have emphasized its occurrence in buffaloes. This article describes the epidemiological, clinical and pathological aspects and diagnosis of psoroptic mange in buffaloes in a property in the municipality of Castanhal, PA, Amazon region. Of the 41 buffaloes examined, 38 males and females of the Murrah, Baio, Mediterranean and Carabao breeds and their crossbreeds, aged between 2 and 20 years, had a history of pruritus. Clinical examination was performed to map the lesions, skin scrapings were collected to identify the mites, and a biopsy was performed for histopathological examination. Clinical signs, from mild to severe intensity, varied according to the system of creation and handling of the animals and were more severe in buffaloes raised in bays than those raised under a collective regime (pastures and collective troughs). The characteristic clinical signs were intense itching, extensive areas of alopecia, periocular edema, and thickening of the epidermis with exudative crusts covering the face, chamfer, neck, scapular region, back, base of the horn, thoracic and pelvic limbs and chest. The behavior of rubbing the affected regions of the body against structures (troughs, fence posts, gates) or with the horns was frequently observed and provided relief from itching. In the most severe cases, mites were also noted in the crusts, which were identified as Psoroptes natalensis. Histological skin lesions exhibited alterations consistent with immune-mediated dermatitis, which is typical of hypersensitivity to mite-derived allergens.

Assessment of the in vitro acaricidal activity of Bravecto® (fluralaner) and a proposed orange oil-based formulation vehicle for the treatment of Sarcoptes scabiei.

BACKGROUND: Sarcoptic mange is a serious animal welfare concern in bare-nosed wombats (Vombatus ursinus). Fluralaner (Bravecto®) is a novel acaricide that has recently been utilised for treating mange in wombats. The topical 'spot-on' formulation of fluralaner can limit treatment delivery options in situ, but dilution to a volume for 'pour-on' delivery is one practicable solution. This study investigated the in vitro acaricidal activity of Bravecto, a proposed essential oil-based diluent (Orange Power®), and two of its active constituents, limonene and citral, against Sarcoptes scabiei. METHODS: Sarcoptes scabiei were sourced from experimentally infested pigs. In vitro assays were performed to determine the lethal concentration (LC50) and survival time of the mites when exposed to varying concentrations of the test solutions. RESULTS: All compounds were highly effective at killing mites in vitro. The LC50 values of Bravecto, Orange Power, limonene and citral at 1 h were 14.61 mg/ml, 4.50%, 26.53% and 0.76%, respectively. The median survival times of mites exposed to undiluted Bravecto, Orange Power and their combination were 15, 5 and 10 min, respectively. A pilot survival assay of mites collected from a mange-affected wombat showed survival times of < 10 min when exposed to Bravecto and Orange Power and 20 min when exposed to moxidectin. CONCLUSIONS: These results confirm the acaricidal properties of Bravecto, demonstrate acaricidal properties of Orange Power and support the potential suitability of Orange Power and its active constituents as a diluent for Bravecto. As well as killing mites via direct exposure, Orange Power could potentially enhance the topical delivery of Bravecto to wombats by increasing drug penetration in hyperkeratotic crusts. Further research evaluating the physiochemical properties and modes of action of Orange Power and its constituents as a formulation vehicle would be of value.

Co-infection patterns in the ectoparasitic community affecting the Iberian ibex Capra pyrenaica.

BACKGROUND: Sarcoptic mange is one of the main parasitic diseases affecting the Iberian ibex Capra pyrenaica. Scabietic animals suffer a decline in body condition and reproductive fitness and in severe cases may die. Although several previous studies of the pathology of this disease and the physiological changes it produces in ibex have been carried out in recent years, our knowledge of the relationship between Sarcoptes scabiei and other ectoparasites of this host is still limited. METHODS: We analysed 430 Iberian ibex skin samples. Ectoparasites were removed, counted and identified. Mite (S. scabiei) numbers were obtained after digesting the skin samples in a 5% KOH solution. We modelled mite numbers in terms of host sex and age, site, year, season and the presence of other ectoparasites such as ticks and lice using generalized linear mixed models (GLMMs) and ectoparasite co-occurrence patterns using two different models: the probabilistic model species co-occurrence and the generalized linear latent variable model (GLLVM). RESULTS: The ectoparasite community was mainly composed of S. scabiei, six ticks (Haemaphysalis sulcata, Haemaphysalis punctata, Rhipicephalus bursa, Rhipicephalus turanicus, Dermacentor marginatus and Ixodes ricinus) and two lice (Bovicola crassipes and Linognathus stenopsis). Adult male ibex harboured more mites than females. Mite numbers varied greatly spatially and seasonally and increased with the presence of other parasites. Some positive co-occurrence relationships between pairs of different ectoparasites were observed, particularly between ticks. The presence of S. scabiei negatively affected lice and H. sulcata numbers. CONCLUSIONS: Sarcoptic mange has spread above all in ibex populations in and around the Mediterranean Basin, where it is now found in almost a third of its host's range. Mite numbers varied seasonally and spatially and were higher in male hosts. The presence of S. scabiei had a negative effect on lice numbers but favoured the presence of ticks.

Effects of Sarcoptes scabiei Translationally Controlled Tumor Protein (TCTP) on Histamine Release and Degranulation of KU812 Cells.

Scabies is a common parasitic dermatological infection worldwide that is often neglected. Scabies mites stimulate host inflammatory symptoms via secreted and excreted proteins, which induce basophil and mast cell degranulation and host histamine release. However, the mechanism of degranulation and histamine release is unclear. Moreover, the Sarcoptes scabiei translationally controlled tumor protein (TCTP) is predicted as an excreted protein, which may be involved in host inflammatory response regulation. First, we evaluated S. scabiei TCTP gene (SsTCTP) transcription in larvae, nymphs, and adults by qRT-PCR, and SsTCTP transcription was highest in larvae, followed by nymphs. Second, we found that the S. scabiei TCTP recombinant protein (rSsTCTP) promoted mice histamine release in vivo by Evans blue Miles assay. Therefore, to further explore the possible role of S. scabiei TCTP in host inflammatory response regulation, we established a degranulation model of KU812 cells. The results of the degranulation model suggested that rSsTCTP could induce enhanced degranulation of KU812 cells and increase the secretion of histamine and the expression of IL-4, IL-6, and IL-13 in vitro. In conclusion, we speculate that scabies mites could stimulate host histamine release and Th2 response by excreting S. scabiei TCTP.

Prevalence of Sarcoptes scabiei in Patients with Suspected scabies

Objective: Scabies is caused by an ectoparasite called Sarcoptes scabiei (S. scabiei), which penetrates the epidermis through skin folds and burrows in the stratum corneum, following the development of tunnels (sillion). The disease is specifically characterised by keratosis, allergy and itching that increases at night-time. This study aimed to investigate the frequency of S. scabiei in patients with a pro-diagnosis of scabies. Objective: Between January 2012 and December 2019, a total of 746 [n=388 (52%), female; n=358 (48%) male] patients aged 0-80 years were admitted to Firat University Hospital Parasitology-mycology Laboratory. Skin scrapings were taken from suspected lesions on anatomic regions such as the hands (wrist, interdigital skin, fingertip and palm), abdomen, penis and legs (thigh and bottom foot). They were examined under a light microscope after adding 15% potassium hydroxide solution. Results: S. scabiei was positive in 139 (18.63%) of 746 patients including a mother and her daughter and a married couple, where 68 (9.11%) were female and 71 (9.52%) were male. Conclusion: To our best knowledge, this is the first comprehensive study of scabies in Elazig. Despite the recent socio-economic and cultural developments observed in our country, scabies and all other parasitic infestations still remain to be important problems. We believe that improvement of the public vigilance together with early diagnosis will improve sanitation and provide protection against scabies and parasitic infestations.

A unique group of scabies mite pseudoproteases promotes cutaneous blood coagulation and delays plasmin-induced fibrinolysis.

BACKGROUND: Scabies, a highly contagious skin disease affecting more than 200 million people worldwide at any time, is caused by the parasitic mite Sarcoptes scabiei. In the absence of molecular markers, diagnosis requires experience making surveillance and control challenging. Superficial microthrombi in the absence of vasculitis in scabies-affected skin are a recognised, yet unexplained histopathological differential of scabies infection. This study demonstrates that a family of Scabies Mite Inactivated Cysteine Protease Paralogues (SMIPP-Cs) excreted by the mites plays a role in formation of scabies-induced superficial microthrombi. METHODOLOGY/PRINCIPAL FINDINGS: A series of in vitro and ex vivo experiments involving two representative recombinant SMIPP-Cs was carried out. In the presence of SMIPP-Cs, the thrombin clotting time (TCT), fibrin formation and plasmin induced fibrinolysis were monitored in vitro. The ultrastructure of the SMIPP-C-modulated fibrin was analysed by Scanning Electron Microscopy (SEM). Immuno-histological analyses were performed ex vivo, to localise the SMIPP-C proteins within scabies infected skin biopsies. SMIPP-Cs displayed pro-coagulant properties. They bound calcium ions, reduced the thrombin clotting time, enhanced the fibrin formation rate and delayed plasmin-induced fibrinolysis. The SMIPP-Cs associated with fibrin clots during fibrinogen polymerisation and did not bind to preformed fibrin. Scanning electron microscopy revealed that the fibrin clots formed in the presence of SMIPP-Cs were aberrant and denser than normal fibrin clots. SMIPP-Cs were detected in microthrombi which are commonly seen in scabietic skin. CONCLUSIONS/SIGNIFICANCE: The SMIPP-Cs are the first scabies mite proteins found in sub-epidermal skin layers and their pro-coagulant properties promote superficial microthrombi formation in scabetic skin. Further research is needed to evaluate their potential as diagnostic or therapeutic target.

Treatment of sarcoptic and chorioptic mange in an alpaca (Vicugna pacos) herd with a combination of topical amitraz and subcutaneous ivermectin.

Clinical history: An outbreak of intense pruritus and weight loss in a herd of 40 alpacas (Vicugna pacos) in the south-west of France was investigated after the death of 14 adults. One alpaca was referred to a veterinary teaching hospital for diagnosis and treatment but died soon after and one of the dead alpacas was submitted for necropsy. Clinical findings: The remaining alpacas were intensely pruritic with variably severe and extensive alopecia, erythema, lichenification and crusting on the face, ventral abdomen and distal limbs. Superficial skin scrapes from five animals revealed large numbers of Sarcoptes scabiei mites, and less frequent and numerous Chorioptes bovis mites. Coproscopic examinations revealed a median of 1,350 (min 500, max 8800) strongyle epg. The alpaca admitted for treatment was anaemic and hypoalbuminaemic. Skin scrapes revealed copious S. scabiei and C. bovis mites. The two alpacas examined post-mortem had similar skin lesions to those examined on-farm and were cachexic. One had lung lesions attributed to protostrongylid infestation and its liver contained numerous Dicrocoelium spp. adults. Diagnosis: Sarcoptic and chorioptic mange with secondary superficial bacterial skin infection, associated with severe internal parasitism and underfeeding. Treatment and outcome: All 25 alpacas were treated topically with a 3% chlorhexidine shampoo followed by a 0.025% amitraz wash at the initial visit and then 1, 2, 3, 7 and 9 weeks later. A systemic treatment with S/C 500 µg/kg ivermectin was administered at the initial visit and then 2, 7 and 9 weeks later. The alpacas were treated orally with 50 mg/kg praziquantel to control dicrocoeliosis. Nutritional measures, including increased pasture area and supplemental feeding were simultaneously implemented. Pruritus was reduced 1 week after the start of treatment and had resolved after 2 weeks. After 9 weeks, skin lesions were markedly improved. Six months after the initial visit, skin lesions entirely resolved and superficial skin scrapes, taken from half of the animals, were negative for mites. Clinical relevance: This is the first report of the use of two acaricides combined with a chlorhexidine shampoo to successfully treat simultaneous sarcoptic and chorioptic mange in alpacas.

A Tissue Digestion Protocol for Measuring Sarcoptes scabiei (Astigmata: Sarcoptidae) Density in Skin Biopsies.

Sarcoptic mange is a parasitic skin disease caused by the burrowing mite Sarcoptes scabiei that affects a diversity of mammals, including humans, worldwide. In North America, the most commonly affected wildlife includes wild canids, such as coyotes and red foxes, and more recently American black bears in the Mid-Atlantic and Northeast United States. Currently, surveillance for sarcoptic mange in wildlife is syndromic, relying on detection of clinical signs and lesions, such as alopecia and crusting of skin. When possible, skin scrapes are used to identify the causative mite. While skin scrapes are a valuable diagnostic tool to identify mites, this approach has significant limitations when used for quantification of mite burden. To further investigate mite burden in cases of sarcoptic mange, 6-mm punch biopsies were collected from affected skin of red foxes (Vulpes vulpes Linnaeus [Carnivora: Canidae]), a species historically affected by sarcoptic mange, frequently with high mite burdens and severe skin disease, and validated on skin tissue from mange-affected American black bears (Ursus americanus Pallas [Carnivora: Ursidae]) and coyotes (Canis latrans Say [Carnivora: Canidae]). Biopsies were digested by incubating the tissue in potassium hydroxide (KOH) at 55°C. The greatest tissue clearance and lowest mite degradation resulted after 12 h of tissue digestion. The purpose of this manuscript is to describe a methodology for host tissue digestion and mite quantification in cases of sarcoptic mange. This method will provide a valuable surveillance and research tool to better understand sarcoptic mange in wild and domestic animals, with applications to a diversity of other ectoparasitic diseases.

Scabies and impetigo in Timor-Leste: A school screening study in two districts.

INTRODUCTION: Scabies and impetigo are common and important skin conditions which are often neglected in developing countries. Limited data have been published on the prevalence of scabies and impetigo in Timor-Leste. Sequelae including cellulitis, bacteraemia, nephritis, acute rheumatic fever and rheumatic heart disease contribute significantly to the burden of disease. METHODS: School students were recruited from schools in Dili (urban) and Ermera (rural) in Timor-Leste for an epidemiological study in October 2016. A standard questionnaire was used to record demographics, anthropometry and skin examination results. Impetigo and scabies were diagnosed based on clinical examination of exposed surfaces, and clinical photographs were reviewed for correlation by an infectious diseases paediatrician. Prevalence of scabies and impetigo were calculated and binary risk factor associations were described using relative risks and 95% confidence intervals. Adjusted odds ratios were calculated using logistic regression multivariate analysis. Continuous variables were analysed for associations using the Mann-Whitney Rank Sum test. RESULTS: The study enrolled 1396 students; median age 11 years (interquartile range (IQR) 9-15). The prevalence of scabies was 22.4% (95% CI 20.2-24.7%) and active impetigo 9.7% (95% CI 8.3-11.4%); 68.2% of students had evidence of either active or healed impetigo. Students in Ermera were more likely than those in Dili to have scabies (prevalence 32.0% vs 5.2%, aOR 8.1 (95% CI 5.2-12.4), p<0.01). There was no difference in the prevalence of active impetigo between urban and rural sites. More than a third of participants were moderately or severely underweight. Stunting was markedly more common in the rural district of Ermera. CONCLUSION: Scabies and impetigo are common in Timor-Leste, with very high prevalence of scabies in the rural district of Ermera. Improvements in prevention and treatment are needed, with prioritised activities in the rural areas where prevalence is highest.

Phylogenetic relationships, stage-specific expression and localisation of a unique family of inactive cysteine proteases in Sarcoptes scabiei.

BACKGROUND: Scabies is worldwide one of the most common, yet neglected, parasitic skin infections, affecting a wide range of mammals including humans. Limited treatment options and evidence of emerging mite resistance against the currently used drugs drive our research to explore new therapeutic candidates. Previously, we discovered a multicopy family of genes encoding cysteine proteases with their catalytic sites inactivated by mutation (SMIPP-Cs). This protein family is unique in parasitic scabies mites and is absent in related non-burrowing mites. We postulated that the SMIPP-Cs have evolved as an adaptation to the parasitic lifestyle of the scabies mite. To formulate testable hypotheses for their functions and to propose possible strategies for translational research we investigated whether the SMIPP-Cs are common to all scabies mite varieties and where within the mite body as well as when throughout the parasitic life-cycle they are expressed. RESULTS: SMIPP-C sequences from human, pig and dog mites were analysed bioinformatically and the phylogenetic relationships between the SMIPP-C multi-copy gene families of human, pig and dog mites were established. Results suggest that amplification of the SMIPP-C genes occurred in a common ancestor and individual genes evolved independently in the different mite varieties. Recombinant human mite SMIPP-C proteins were produced and used for murine polyclonal antibody production. Immunohistology on skin sections from human patients localised the SMIPP-Cs in the mite gut and in mite faeces within in the epidermal skin burrows. SMIPP-C transcription into mRNA in different life stages was assessed in human and pig mites by reverse transcription followed by droplet digital PCR (ddPCR). High transcription levels of SMIPP-C genes were detected in the adult female life stage in comparison to all other life stages. CONCLUSIONS: The fact that the SMIPP-Cs are unique to three Sarcoptes varieties, present in all burrowing life stages and highly expressed in the digestive system of the infective adult female life stage may highlight an essential role in parasitism. As they are excreted from the gut in scybala they presumably are able to interact or interfere with host proteins present in the epidermis.

Scabietic vasculitis: Report of 2 cases.

BACKGROUND: The infectious causes of cutaneous vasculitis are well known and include streptococcal infections among others. Cases resulting from parasitic infection are less frequent. Scabies, which is currently on the increase, has only been reported in a few isolated cases. Herein, we report two noteworthy cases of profuse scabies complicated by cutaneous vasculitis. PATIENTS AND METHODS: Case 1: a 90-year-old woman, residing in a nursing home, was admitted to our dermatology department complaining of pruritus, present for one month, predominantly on the inside of the thighs and on the buttocks, associated with purpuric lesions on the lower limbs. A skin biopsy revealed leukocytoclastic vasculitis. A diagnosis of scabies was based on severe pruritus and hypereosinophilia and was confirmed by microscopic examination of the parasitology sample and the skin biopsy sample. Despite thorough investigation, no other cause of vasculitis could be found. Complete regression of the skin lesions was achieved with scabies treatment only, without any specific treatment for the vasculitis. Case 2: a 74-year-old man, living in a nursing home, was hospitalized for purpuric papules on the lower limbs, present for one month. Physical examination revealed linear patterns in the interdigital spaces associated with scabies evident on dermoscopic examination. The skin biopsy revealed signs of vasculitis. As in our first case, no aetiology of vasculitis was found and a favorable outcome was achieved by means of scabies treatment alone with no specific treatment for vasculitis. DISCUSSION: Both of our patients presented scabies and vasculitis. In view of the absence of other causes of vasculitis and of the complete regression of lesions due to vasculitis without recurrence achieved with the scabies treatment alone, a diagnosis was made of scabietic vasculitis, probably as a result of cutaneous hypersensitivity reaction to humeral mediators.

Scabies in a bilateral hand allograft recipient: An additional mimicker of acute skin rejection in vascularized composite allotransplantation.

Vascularized composite tissue allografts include skin, which frequently undergoes, in the early post-graft period, acute rejections. The diagnosis of acute rejection may be difficult as it can be mimicked by several dermatoses. We present a bilateral hand allograft recipient who developed, 16.5 years post-graft, cutaneous lesions raising suspicion about rejection. Physical examination and skin biopsy were diagnostic of scabies. This ectoparasitosis should be added in the list of dermatoses that can mimic allograft rejection in vascular composite allografts.

Vaccination of rabbits with immunodominant antigens from Sarcoptes scabiei induced high levels of humoral responses and pro-inflammatory cytokines but confers limited protection.

BACKGROUND: Vaccination is an attractive ecological alternative to the use of acaricides for parasite control. However, effective anti-parasite vaccines against sarcoptic mange have not yet been developed. The purpose of this study was first to identify Sarcoptes scabiei immunodominant antigens and second to evaluate them as vaccine candidates in a rabbit/S. scabiei var. cuniculi model. METHODS: The S. scabiei Ssλ15 immunodominant antigen was selected by immunoscreening of a S. scabiei var. hominis cDNA. The full-length cDNA was sequenced and cloned into the pGEX vector and the recombinant protein expressed in BL21 (DE3) cells and purified. A vaccination trial was performed consisting of a test group (n = 8) immunised with recAgs (a mix of two recombinant antigens, Ssλ15 and the previously described Ssλ20∆B3) and a control group (n = 8) immunised with PBS. All analyses were performed with R Statistical Environment with α set at 0.050. RESULTS: The full-length open reading frame of the 1,821 nt cloned cDNA encodes a 64 kDa polypeptide, the sequence of which had 96 % identity with a hypothetical protein of S. scabiei. Ssλ15 was localised by immunostaining of skin sections in the tegument surrounding the mouthparts and the coxa in the legs of mites. Rabbit immunisation with recAgs induced high levels of specific IgG (P < 0.010) and increased levels of total IgEs. However, no significant clinical protection against S. scabiei challenge was detected. Unexpectedly, the group immunised with the recAgs mix had significantly higher lesion scores (P = 0.050) although lower mean mite densities than those observed in the control group. These results might indicate that the lesions in the recAgs group were due not only to the mites density but also to an exacerbated immunological response after challenge, which is in agreement with the specific high levels of pro-inflammatory cytokines (IL-1 and TNFα) detected after challenge in this group. CONCLUSIONS: The selected antigens delivered as recombinant proteins had no clinical protective efficacy against S. scabiei infestation although immunisation reduced mite density. However, these results pave the way for future studies on alternative production systems, adjuvants, delivery methods and combinations of antigens in order to manage stimulation of clinical protective immune responses.

Serie parasitosis en dermatología: escabiosis / Series parasitosis in dermatology: scabies

La escabiosis es una ectoparasitosis pruriginosa producida por el ácaro Sarcoptes scabiei, variedad hominis, específica del ser humano. Si bien su distribución es universal, con frecuencia es subdiagnosticada por asociarla únicamente a hacinamiento y malos hábitos de higiene. Se transmite por contacto directo con una persona afectada o a través de fómites, por lo que es muy común el contagio de los convivientes. Presentamos un caso de escabiosis en una paciente anciana evaluada por prurito generalizado. (AU)

Scabies is a human specific pruritic ectoparasitosis produced by the mite Sarcoptes scabiei var. hominis. Although it has a worldwide distribution, it is often underdiagnosed because it is only associated with overcrowding and poor hygiene. It is transmitted by a direct contact with an affected person or through fomites. The transmission to cohabitants is very common. We present a case of scabies in an elderly patient with generalized pruritus. (AU)

Acute phase proteins increase with sarcoptic mange status and severity in Iberian ibex (Capra pyrenaica, Schinz 1838).

Sarcoptic mange is a contagious skin disease caused by Sarcoptes scabiei, affecting both domestic and wild mammals, including the Iberian ibex (Capra pyrenaica), a medium-sized mountain ungulate almost endemic to the Iberian Peninsula. Acute phase proteins (APPs) could be an indicator of sarcoptic mange disease and severity in Iberian ibex. Serum samples from 131 healthy and sarcoptic mange-affected Iberian ibexes were collected from 2005 to 2012 in Sierra Nevada Natural Space in southern Spain. Serum alpha-1-acid glycoprotein (AGP), serum amyloid A (SAA) and haptoglobin (Hp) concentrations were quantified, and statistically significant differences according to sarcoptic mange disease and severity were assessed. Both AGP and SAA were significantly higher in the sarcoptic mange-affected ibexes than in the healthy ones as well as in the severely affected ibexes as compared to those with less than 50 % of the body surface affected. For the first time, changes in APP are reported in relation to sarcoptic mange in Iberian ibex. It is also reported for the first time that the intensity of APP increase depends on the severity of sarcoptic mange, which could be related with the pathological secondary amyloidosis, leading to organ dysfunction in severely mange-affected animals. Species and population differences in the increase of APP in response to sarcoptic mange could indicate individual and population differences in the immune capability of each population to deal with mange, population prevalence and mortality being the last indicators of such sensitivity.

Superficial fibrin thrombi and other findings: a review of the histopathology of human scabietic infections.

BACKGROUND: Cutaneous infection with the mite Sarcoptes scabiei var. hominis is associated with epidermal and dermal changes. After noting superficial fibrin thrombi in two biopsies with scabies mites, we comprehensively reviewed the histopathologic findings in scabietic infections to determine the frequency of this finding. METHODS: Twenty five biopsies of scabies infection were retrieved from the archives of our institution; only cases containing scabietic mite parts or scybala were included. The microscopic features were documented. RESULTS: Nearly half (40%) of the cases showed fibrin thrombi within vessels of the superficial dermis. Other frequent findings included dermal eosinophils (88% of cases), epidermal spongiosis (76% of cases), lymphocyte atypia (64%), a superficial and deep infiltrate (52% of cases), dermal neutrophils (52%) and endothelial cell swelling (52%). Half of the cases contained polarizable mite elements. Less commonly encountered features included extravasated erythrocytes (44%), dermal edema (32%), pink 'pigtails'(28%), intraepidermal pustules (24%), plasma cells (20%) and vasculitis (4%). CONCLUSIONS: The pathologic characteristics of scabietic infection are wide-ranging. Spongiosis, superficial and deep inflammation, and dermal eosinophils and neutrophils are seen in the majority of cases. Superficial fibrin thrombi are not uncommon in scabietic infection, and may provide a helpful diagnostic clue when mites are not visible on initial sections.