Lichenoid Pattern Research Articles

Clinicopathologic characteristics of cutaneous chronic graft‐versus‐host diseases: a retrospective study in Korean patients

Chronic graft-versus-host disease (cGVHD) is a major complication in long-term survivors of hematopoietic stem cell transplantation (HSCT). Cutaneous manifestations are frequently the presenting features; therefore, the dermatologist needs to be aware of the wide spectrum of cutaneous cGVHD. We retrospectively evaluated patients' characteristics, clinical, and histological features of cutaneous cGVHD and analyzed factors influencing the severity of cutaneous cGVHD in 100 Korean HSCT recipients between January 1, 1995, and December 31, 2007. Clinical manifestations of cutaneous cGVHD mainly presented as lichenoid (60.0%), sclerodermoid (12.0%), or erythematous maculopapular (22.0%) patterns. Other less common findings included xerosis, dyspigmentation, acquired ichthyosis, eczema, exfoliative dermatitis, alopecia, erythema multiforme-like or keratosis pilaris-like eruption. Among 100 patients, 46 patients were investigated for nail involvement, and 29 (63.0%) of them were accompanied with nail abnormalities. Histologically, characteristic lichenoid lesions were observed in 53%, sclerodermoid in 9%, and acute/chronic overlap syndrome in 28% of patients. We also discovered that HSCT from female donors to male recipients increased the severity of cutaneous cGVHD. We report a large study about cutaneous cGVHD in Asian patients. Cutaneous cGVHD presented with a wide spectrum of clinical and histological manifestations.

Lichenoid Inflammation in Cutaneous Cysts

To the Editors: We recently observed a case of a benign epidermoid cyst with a prominent lichenoid reaction. A 49-year-old man with a history of hyperlipidemia controlled on simvastatin presented with a “boil” on his back of 2 weeks duration. It was felt to be a carbuncle and treated with incision and drainage, iodoform gauze packing, and the cephalexin before excision. Histologic exam revealed a cyst lined by stratified squamous epithelium with a granular layer. The cyst cavity contained orthokeratin, foreign body giant cells, neutrophils, and early granulation tissue. Nearly the entire epithelial lining demonstrated a saw-toothed rete pattern, dense band-like lymphoplasmacytic inflammation, and prominent Civatte bodies (Figs. 1 and 2).FIGURE 1: Low power of ruptured cyst with lichenoid inflammation throughout the majority of the cyst lining.FIGURE 2: High power of the lichenoid inflammation.Typically, when an epidermoid cyst ruptures, a suppurative and granulomatous foreign-body response is seen. As discussed by Weedon, a number of histologic changes have been seen in the lining of epidermoid cysts: epidermal proliferation, basal hyperpigmentation, melanophagic proliferation, pilomatricoma-like changes, clear cell change, coronoid lamellation, epidermolytic hyperkeratosis, changes of Darier disease, pyogenic granuloma formation, and a number of tumors.1 We are unaware of previous reports of a lichenoid interface dermatitis found in the lining of an epidermoid cyst. A Medline search using the methodology “cyst AND (lichenoid OR interface AND dermatitis)” failed to reveal prior reports. However, an electronic search of our pathology database over the last 10 years revealed 9 additional cases of cutaneous cysts with a lichenoid inflammatory response. All cases involved epidermoid cysts, and in all cases the lichenoid pattern was only focal. In 2 cases, there was overlying lichenoid inflammation and lichen simplex chronicus-like epidermal changes (Table 1).TABLE 1: Retrieved Cases of Cutaneous Cysts With Lichenoid InflammationThe significance of these changes is not known. Lichenoid interface dermatitis is felt to be mediated by cytotoxic CD8+ T cells that are responding to an unknown stimulus causing destruction of the basal layer epidermal keratinocytes.2 Many lichenoid conditions are linked epidemiologically to autoimmune phenomena and autoantibody formation. Our patient was taking simvastatin, a known cause of lichenoid drug eruptions.3 However, we think the drug is an unlikely cause of the lichenoid tissue reaction in our patient. Eric W. Hossler, MD Morgan L. Wilson, MD Department of Dermatopathology Geisinger Medical Center Danville, PA MAJ Scott R. Dalton, DO, MC, USA Department of Dermatology Geisinger Medical Center Danville, PA Dirk M. Elston, MD Departments of Dermatology and Dermatopathology Geisinger Medical Center Danville, PA

Perivascular Cuff and Spread of Treponema pallidum

Background: The incidence of syphilis is on the rise in many cities worldwide. Both the clinical and histopathological changes do not always fulfil the typical diagnostic criteria. Immunohistochemistry is available to identify and localize Treponema pallidum. Two main patterns of T. pallidum distribution were described in the skin, namely heavy intraepidermal infiltration and scattered pattern inside the lichenoid cell infiltrate. Objective: To search for a third pattern consistent with dissemination of the disease. Methods: Immunohistochemistry using an antispirochete (T. pallidum and Borrelia) antibody was used in all cases of syphilis submitted to our laboratory. In addition, deposits of immunoglobulins and complement indicative of immune complexes were searched for. Results: According to the cases, T. pallidum was disclosed in a combination of three patterns. The previously described epidermal and lichenoid patterns were confirmed, and a third pattern predominating in a perivascular location throughout the dermis was clearly identified in primary syphilis. The microorganisms were abundant in extracellular and intracellular locations, particularly inside endothelial cells. No deposits of immunoglobulins and complement were disclosed. Conclusion: The perivascular cuff of T. pallidum throughout the dermis might be representative of the dissemination phase of T. pallidum.

Annular Lichenoid Dermatitis of Youth … and Beyond: A Series of 6 Cases

Annular lichenoid dermatitis of youth (ALDY) is a clinico-pathologic entity described in children and young patients, clinically reminiscent of morphea, annular erythema, vitiligo or mycosis fungoides. We report on six patients presenting single or multiple lesions, distributed particularly on the flanks and abdomen, with clinical and histologic features consistent with ALDY. Two patients were young girls and four were adults males. Three patients received topical therapy and four showed complete resolution of the lesions after a 24-65 months follow-up. Analogously to the cases reported so far, immunohistochemistry showed a T cell infiltrate with a predominance of CD8+ lymphocytes, while T cell receptor rearrangement was absent in all cases. It seems appropriate to include annular lichenoid dermatitis of youth among the dermatoses with a lichenoid pattern. For the first time, we found that it can affect also adult patients, therefore we propose to rename the disease annular lichenoid dermatitis. The differential diagnosis with mycosis fungoides, especially in adult patients, is particularly crucial for their proper management and treatment.

Poikilodermatous parapsoriasis - two cases with review of literature

Poikilodermic parapsoriasis is a rare varaint of poikiloderma where the chances of going into mycoses fungoides exists.But not all cases do go to mycoses. In the early stage of poikiloderma atrophicans vasculare, without respect to its course, shows moderate thinning of stratum malpigji, effacement of rete ridges, hydropic degeneration of basal cells. In the upper dermis-there is band like infiltrate which in places invades the epidermis. The infiltrate consists of a few histiocytes-so called initial 'lichenoid pattern'. In addition there is abundance of melanophages with pigment incontinence. In late stages there is thinning of is with hydropic degeneration of basal cells. In MF inflammatory infiltrate increases rather than decreases in time. Large hyperchromatic nuclei, so called 'mycoses cells' are likely to be present in this variant and often there is moderate to marked epidermotropism. It may result in Pautrier microabscess. formation.The diagnosis of Mycoses Fungoides is supported by presence of an aberrant phenotype, for example T cell lacking one or more pan T cell antigens. Most commonly absent antigen is CD-7 followed by CD-2, CD-3 and CD-5³ . Making a differential diagnosis between early MF and parapsoriasis is often difficult at clinical and histological level. We report two cases of poikilodermic parapsoriasis, both showing some degree of epidermotropism ,but one had panT cell marker CD 3, CD5, CD7 present and other absent.The lady with Pan T cell markers did not progress to frank mycoses fungoides while the patient with absent markers progressed rapidly and finally succumbed.

Giant cell lichenoid dermatitis in a patient with baboon syndrome

Giant cell lichenoid dermatitis is a recently described pathological entity, which can be seen as an unusual lichenoid drug eruption, a manifestation of sarcoidosis or within herpes zoster scars. Histopathological findings include focal vacuolar alteration of the basal layer with cytoid bodies, dermal and intraepidermal multinucleated giant cells and a mixed chronic inflammatory infiltrate with a lichenoid pattern consisting of lymphocytes, histiocytes, eosinophils and plasma cells. Here, we report a giant cell lichenoid dermatitis in a 41-year-old male patient who developed, 3 days after intravenous treatment with amoxicillin-clavulanic acid for erysipelas of the left leg, a clinical picture suggesting a baboon syndrome characterized by an erythematous and pruritic eruption on the axillary, inguinal and popliteal areas and the anterior side of elbows. This is the first reported case of giant cell lichenoid dermatitis in a patient with baboon syndrome.

Lichenoid Sarcoidosis: A Case With Clinical and Histopathological Lichenoid Features

Sarcoidosis is a chronic multisystemic granulomatous disease of unknown etiology, characterized by the formation of noncaseating granulomas in the involved organs. Cutaneous involvement is about 25% with different clinical expressions, the lichenoid pattern being one of the rarest types of cutaneous sarcoidosis. Lichenoid sarcoidosis clinically manifests with multiple scale papules involving extensive skin areas, especially the trunk, limbs, and face mimicking a lichen planus. Although diverse histologic patterns have been previously related, a lichenoid granulomatous infiltrate involving the dermo-epidermal junction has never been reported in lichenoid sarcoidosis. We report a case of a 43-year-old woman presenting with skin-colored pruritic papules, slightly scaling in trunk, extremities, and ears. These symptoms condition continued to expand and worsen for several years. The patient was otherwise in good health with no lymphadenopathies. Histopathologic examination of a skin biopsy showed an upper dermal granulomatous infiltrate of epithelioid cells, without necrosis, distributed in a lichenoid pattern with many cytoid bodies. We consider this may be the first case presenting a characteristic microscopic granulomatous lichen-like pattern in the setting of a clinically lichenoid type of sarcoidosis.

Safety and Tolerability of Adjuvant Topical Tacrolimus Treatment in Boys with Lichen Sclerosus: A Prospective Phase 2 Study

BackgroundManagement of lichen sclerosus (LS) in boys is still controversial. Although in most cases only the prepuce is affected, meatal and urethral involvement may require major surgical reconstruction with substantial morbidity. ObjectiveBecause the frequency of such complicated courses is still unclear, an adjuvant postoperative treatment is highly desirable. Therefore, we addressed safety and tolerability of tacrolimus 0.1% ointment in the postoperative period. Design, Setting, and ParticipantsAmong 222 penile surgeries, in 25 cases LS was confirmed histologically and 20 of those patients participated in the adjuvant treatment study. Moreover, 18 patients of the same cohort showed a lichenoid inflammatory reaction pattern suggestive of early but not fully established LS. Interventions and MeasurementsSubsequent to the operation and after explicit information about off-label use, parents applied tacrolimus 0.1% ointment twice daily to the glans and the meatus for 3 wk in cases of proven LS. The 18 patients with possible early LS were followed up only without any treatment. Clinical follow-up was performed up to 13 mo (median). Results and LimitationsAll 20 LS patients completed the topical treatment without any relevant side-effects. Two relapses occurred in the treatment group and were clinically cured with an additional 3-wk cycle of topical tacrolimus 0.1% ointment. None of the 18 early LS cases progressed to full-scale LS. ConclusionsThis is the first study showing that tacrolimus 0.1% ointment applied immediately after surgery of fully established LS is a tolerable and most probably safe adjuvant novel treatment option. Because the therapy led to disease control in all treated individuals for >1 yr (median), this study establishes the groundwork for future trials with expanded treatment and follow-up periods to verify the true clinical benefit of tacrolimus in patients after LS surgery. Lichenoid tissue reactions suggestive of early LS seem to require no adjuvant treatment.

Herpes Incognito Most Commonly Is Herpes Zoster and Its Histopathologic Pattern Is Distinctive!

Infections of the skin by herpesviruses do not always present themselves in typical fashion. Conventional microscopy is used routinely to confirm infection by herpesviruses, but sometimes typical signs such as multinucleated epithelial cells or "ghosts" of them are not encountered in a specimen (so-called herpes incognito). We studied 35 patients in whom infection with herpesviruses was differentially diagnosed clinically but in whom a biopsy specimen had been taken for confirmation. Only those patients in whom histopathologic findings had been interpreted as being "not diagnostic" of herpesvirus infection by 2 independent dermatopathologists were included. Clinical and histopathologic findings were correlated with results from polymerase chain reaction studies on formalin-fixed paraffin-embedded tissue. Polymerase chain reaction revealed herpesvirus-specific DNA in 12 of 35 specimens, 10 being varicella zoster virus (VZV) positive, 1 herpes simplex virus (HSV)-2 positive, and 1 HSV-1 positive. Ten of these 12 cases presented themselves in very similar fashion (8 VZV, 1 HSV-1, 1 HSV-2). All lesions were macular or papular and typified mostly by dense perivascular and sparse interstitial superficial and deep infiltrates of lymphocytes, sometimes assuming a patchy lichenoid pattern. Infiltrates were prominent in and around adnexal structures, often peppering follicles, sebaceous glands, and eccrine glands. Lymphocytes were also found in the lower part of the epidermis accompanied by a combination of spongiosis and vacuolar alteration. The papillary dermis was often edematous; extravasated erythrocytes in variable numbers were a common finding. Lymphocytes sometimes had large and polygonal nuclei. Neutrophils and nuclear dust were present occasionally; eosinophils were rare. We conclude that herpes incognito most commonly is herpes zoster and its histopathologic pattern is distinctive.

A Case of Lichenoid Drug Eruption Associated with Sildenafil Citratus

A 53-year-old man developed lichenoid lesions on the upper chest, posterior surfaces of the trunk, and abdominal region about three months before his first visit. Physical examination and laboratory findings were normal; histopathology showed vacuolar degeneration of basal keratinocytes in association with a dense lympho-histioid infiltrate arranged in a lichenoid pattern with a few melanophages and eosinophils. The fact that our patient had been irregularly taking sildenafil citratus (Viagra) led to the hypothesis of a lichenoid drug-induced eruption. Our hypothesis was confirmed by clinical resolution three weeks after discontinuation of sildenafil citratus; moreover, the patient avoided the drug for about four months, and the eruption didn't reappear. Subsequently, we performed a challenge test with the drug, and the patient developed similar lichenoid lesions. Lichenoid eruptions are rather common dermatoses that can be induced by a great number of environmental agents and are clinically but not pathogenetically well defined. We report the present case because, despite the great number of drugs that can be implicated in the development of lichenoid eruptions, the association of such dermatoses and sildenafil citratus had been described only once previously in the literature until now. Furthermore, we wish to remark on the significance of a detailed anamnestic history to make the correct differential diagnosis between lichenoid drug-induced eruptions and lichen planus. This has a great clinical importance because simple discontinuation or substitution of the drug causes lichenoid drug-induced eruption resolution.

Keratosis lichenoides chronica and eruptive keratoacanthoma‐like lesions in a patient with multiple myeloma

We describe a 72-year-old woman with a 13-year history of a lichenoid dermatitis, who developed multiple, papular keratoacanthoma (KA)-like lesions and few crater-like nodules on the extremities over a period of 6 months before our observation. Her medical history also recorded multiple myeloma diagnosed a few years before. The long-standing dermatosis was diagnosed, clinically, as keratosis lichenoides chronica (KLC), although, histologically, a lichenoid tissue reaction pattern was not evident. On the other hand, histology from papular and nodular lesions of recent onset was consistent with a possible early phase of KA and spinocellular carcinoma, respectively. Oral acitretin induced regression of KA-like lesions and improvement of KLC but had no effects on crater-like nodules, which required surgical excision. KLC is a chronic disorder of keratinization characterized by lichenoid hyperkeratotic papules arranged in a linear pattern, erythematosquamous plaques and seborrhoea-like dermatitis. We emphasize in our case the association between KLC and multiple possible KAs, never previously reported, and speculate that these two rare conditions may represent here a 'continuum' from a pathogenetic point of view.

Prurigo pigmentosa: a distinctive inflammatory disease of the skin.

More than 200 patients with prurigo pigmentosa, a disease described first by Nagashima in 1971, have been reported on in Japan, but only 28 non-Japanese patients have come to notice as of today. In order to establish reliable, repeatable criteria for diagnosis of the disease, we studied 25 patients with prurigo pigmentosa and reviewed the literature pertaining to it as recorded in another 182 patients.Clinically, prurigo pigmentosa presents itself as pruritic urticarial papules, papulovesicles, and vesicles arranged in reticular pattern and distributed symmetrically on the back, neck, and chest. Lesions involute in a matter of days, leaving behind netlike pigmentation. Exacerbations and recurrences are the rule. Histopathologically, prurigo pigmentosa begins with a superficial perivascular infiltrate of neutrophils. Shortly thereafter, neutrophils are scattered in dermal papillae and then sweep rapidly through an epidermis in which spongiosis, ballooning, and necrotic keratocytes are accompaniments. En route, abscesses may form in the surface epithelium. Very soon, eosinophils and lymphocytes come to predominate over neutrophils in a dermal infiltrate that assumes a patchy lichenoid pattern. Intraepidermal vesiculation follows on spongiosis and ballooning and, sometimes, subepidermal vesiculation on vacuolar alteration at the dermo-epidermal junction. As the epidermis becomes hyperplastic, parakeratotic, and slightly hyperpigmented, melanophages begin to appear in the dermis. Studies by immunofluorescence are negative invariably. Dapsone or minocyclin are effective treatments; both of those agents inhibit migration and/or function of neutrophils. The cause and pathogenesis have yet to be determined. Prurigo pigmentosa is unique among inflammatory diseases of the skin and the singularity of it is manifest both clinically and histopathologically.

Lichen striatus

Lichen striatus (LS) is a papulosquamous disorder with a distinctive linear distribution. The linearity has been shown to correspond in many cases to the pattern of Blaschko's lines. The etiology is unknown. LS can usually be identified by clinical history and histology of typical lesions. However, the histologic features are diverse and some have stated they are nonspecific. In an effort to identify those characteristic features, we have reviewed the routine slides in 37 cases for their diagnostic criteria. Ten cases were studied further by immunohistochemistry. The patient's ages ranged from 1.3 to 49 years with mean age of 17.5 years. A female-to-male ratio was 1.6 to 1. The lesions were predominantly distributed on the extremities in 26/34 cases. The consistent histologic features were: hyperkeratosis (29/37), parakeratosis (21/37) with a few necrotic keratinocytes (28/37) in the epidermis, mild spongiosis (29/37) with exocytosis of lymphocytes (33/37). The dermal infiltrate comprised mainly lymphocytes and macrophages. At the dermal-epidermal junction, the infiltrate was either focal (20/37) or lichenoid (17/37) patterns. Superficial and deep perivascular lymphocytic inflammatory infiltrate was present in most of the cases (33/37). Appendageal involvement (34/37) was in hair follicles (24/37) or eccrine glands or ducts (22/37) or both (12/37). Satellite cell necrosis may be seen (11/37). Colloid bodies were present in 16/37 of the cases. Immunohistochemistry showed that most of the small lymphocytes in the upper dermis and epidermis were positive for CD7. Most of the lymphocytes in the epidermis were positive for CD8. CD1a Langerhans' cells were either decreased (5/10) or increased (3/10) or normal (2/10) in the epidermis. The histologic diagnosis of LS can be made on the basis of the combination of these histologic features in the appropriate clinical context. Multiple biopsies may be necessary to determine whether all of these features are present in a given case.

A Reappraisal of the Histopathologic Criteria for the Diagnosis of Cutaneous Allogeneic Acute Graft-vs-Host Disease

To determine the validity of the Lerner grading system and review the histopathologic findings of cutaneous acute graft-vs-host disease (aGVHD), 78 skin biopsy specimens from 49 bone marrow transplant recipients were evaluated. Histopathologic sections were independently reviewed twice by 3 pathologists and classified (Lerner system), without knowledge of the patients' clinical evolution. Intraobserver agreement in grading aGVHD was substantial to almost perfect. Interobserver agreement between pairs of observers was moderate to substantial on first review and substantial on second review. Overall, we found an almost perfect agreement in diagnosing Lerner grade III, whereas areas of disagreement occurred with Lerner grades 0, I, and II. Histopathologically, specimens of patients who developed aGVHD (aGVHD-positive) showed significantly higher frequency of epidermal atrophy, spongiosis, diffuse basal vacuolization, more than 3 single necrotic keratinocytes per high-power field, satellitosis, inflammatory infiltrate, with a predominantly lichenoid pattern, lymphocytic exocytosis, and dermal melanophages. When considering skin samples classified as grade I and II, we found statistically significant differences between aGVHD-positive and aGVHD-negative cases only for the presence of inflammatory infiltrate, lymphocytic exocytosis, and satellitosis. Lerner grading is reproducible, although lesser agreement occurred when evaluating grades I and II, and the Lerner grading system should be revised by including the estimate of the inflammatory infiltrate as an additional criterion for grade II.

Low-Productive Alpha-Herpesviridae Infection in Chronic Lichenoid Dermatoses

Background: Herpes simplex virus (HSV) and Varicella-zoster virus (VZV) are responsible for various atypical mucocutaneous manifestations in the immunosuppressed population. One of the causative pathomechanisms suggests an altered virus-host cell relationship. Objective/Methods: This report investigates by histology, immunohistochemistry and in situ hybridization the histological and virological features of 6 protracted, indolent HSV infections and 2 prolonged zoster infections. Results: Histopathology revealed a lichenoid dermatitis in all patients. Specific HSV-1, HSV-2 and VZV in situ hybridization proved the viral origin of the cutaneous lesions. Immunohistochemical assessment demonstrated the intracellular presence of the HSV glycoproteins gB, gC and gD in epidermal keratinocytes which did not exhibit cytolysis. Similar findings were obtained for the VZV gE and gB. Conclusion: These results suggest that in some instances HSV and VZV infections may present a protracted disease course associated with a lichenoid inflammatory pattern and a non-cytolytic virus-host cell relationship.

Disseminated Superficial Actinic Porokeratosis

The pathology of 61 cases of disseminated superficial actinic porokeratosis was reviewed and the relative frequency of the histological features associated with the cornoid lamella and the pathology within and outside the porokeratotic rim were assessed. Papillary dermal lymphocytic infiltrate (97%), spinous layer vacuolar changes (90%), dyskeratotic cells in the epidermis (77%), and liquefaction degeneration of the basal layer (67%) were frequently seen under the cornoid lamella. Papillary lymphocytic infiltration was seen more frequently inside the porokeratotic ring in comparison to the outer skin. Lymphocyte marker studies in nine cases showed a predominance of activated T lymphocytes with positive LN3 and UCHL-1 staining. Together with the finding of a lichenoid reaction pattern, these results lend support to the hypothesis that actinic porokeratosis represents a migrating clone of abnormal keratinocytes with an associated immunological host response.

DRUG ERUPTIONS WITH LICHENOID HISTOLOGY PRODUCED BY CAPTOPRIL

Three cases are presented with a rash due to captopril which, on histology, showed a lichenoid pattern of bandlike upper dermal infiltrate of lymphocytes and histiocytes, together with hydropic degeneration of the basal layer of the epidermis producing Civatte bodies and pigmentary incontinence. The rash presented either as a pityriasis rosea-like picture which appeared about three to six months after the onset of treatment in patients taking low doses, or alternatively, as lichenoid plaques which appeared three to six months after commencement of medication in patients taking high doses. Although both clinical patterns produced a "saw tooth" pattern of the epidermal rete ridges, hypergranulosis and acanthosis were seen only with the lichenoid plaques.

Scleromyxedema: Therapeutic response to isotretinoin in three patients

Scleromyxedema is a rare type of papular mucinosis that exhibits a generalized lichenoid pattern. A wide variety of clinical manifestations can occur in patients with this disease. Cutaneous involvement is characteristic, but neurologic, cardiovascular, renal, neoplastic, and other systemic manifestations have been described. A monoclonal gammopathy may be present. Many treatment modalities have been used in the past for scleromyxedema. None, however, have shown consistently favorable results. This report concerns the cases of three patients with scleromyxedema who were treated with isotretinoin.

Giant cell lichenoid dermatitis

A case of drug-induced lichenoid dermatitis with an unusual epidermotropic multinucleated giant cell inflammatory response is reported. The patient is a 52-year-old white woman who is steroid-dependent because of long-standing systemic lupus erythematosus. At the time of presentation of her generalized papulosquamous pruritic eruption, she was taking oral antihypertensive medications (methyldopa and chlorothiazide). After discontinuation of these medications and local treatment with topical corticosteroids, the skin eruption dramatically improved. Microscopically, the skin lesions had a lichenoid inflammatory pattern, with multiple cytoid bodies, multinucleated giant cells, and a mixed chronic inflammatory infiltrate that included lymphocytes, histiocytes, and eosinophils.

Chronic Eosinophilic Dermatitis: A Manifestation of a Multisystemic, Eosinophilic, Epitheliotropic Disease in Five Horses

A generalized, chronic, progressive, exfoliative dermatitis in five horses is described. Histologically, the lesion is characterized by a superficial and deep perivascular dermatitis which is eosinophil-rich with a marked lymphocytic and plasmacytic component, accompanied by marked acanthosis and hyperkeratosis. More severe cases progress to a lichenoid pattern with the same cellular composition with focal eosinophilic spongiosis and eosinophilic subcorneal pustules. Clinically, the disease is associated with chronic, severe weight loss and is fulminating. The skin lesions are accompanied by lymphoplasmacytic and eosinophilic infiltrates and formation of eosinophilic granulomas in other epithelial organs, most noticeably the pancreas, in which a chronic, fibrosing pancreatitis develops. Other epithelial organs involved to various degrees are salivary glands, the gastrointestinal system, including the oral cavity and esophagus, biliary epithelium and bronchial epithelium. The etiology of this disease is unknown.