PATTERN; INTERFACE DERMATITIS

PATTERN; INTERFACE DERMATITIS

Erythema Multiforme, (EM) an uncommon, acute inflammatory reactive mucocutaneous disorder and primary allergies confined to the oral mucosa. The diagnosis was established clinically based on the signs and symptoms as erythema multiforme minor associated with herpes simplex infection [2]. That form the basis of their alliterative description as pruritic polygonal purple papules (Figure 8-11). During the acute self-limited course of the illness, management is primarily supportive in providing fluid management and prevention of sepsis. In the EM minor only one mucous membrane is affected, and usually is the oral mucosa. Eruption in mice after inj ection of sensitized, autoreactive T cells. The appearance of the characteristic lesion is usually diagnostic.

FIGURE 8-12 Histopathologic features of lichen planus at low magnification. There is a bandlike infiltrate of lymphocytes thatimpinges on the epidermal-dermal junction, and some keratinocytesadjacent to the infiltrate show cytoplasmic vacuolization. a minor scratch or abrasion, within a week. Some of the T cells are also found within theepidermis, where adjacent vacuolated, injured keratinocytesare found. Dense eosinophilic (pink) globules, known as colloid bodies, are also identifiable within the epidermis and theinfiltrate (Figure 8-13). The conditions in the complex are characterized by the sudden onset of a reddened macular, bullous, papular, or vesicular eruption, the characteristic lesion being the iris, bull’s eye, or target lesion, which consists of a central papule with two or more concentric rings. Although the keratinocytes bear the bruntof the lymphocyte attack, melanocytes may be coincidentallydestroyed in the reaction as “innocent bystanders.” Free melanin pigment is released as melanocytes are damaged, and thepigment is phagocytosed by dermal macrophages known asmelanophages.

The lesions may cause mild itching and burning sensation. If target lesions are present, then diagnosis is clear. Hi I have had erythema multiforme for about 8 years now, it has been an awful time with awful pain included, I have joined this group to be part of a community who understand. In the afferent phase, causative antigens are processed and presented tohelper T cells, probably in the context of specific HLA determinants. The stimulated CD4 lymphocytes then elaboratespecific cytokines that lead to the recruitment of cytotoxiclymphocytes. Cell-mediated cytotoxicity and cytokines suchas interferon-y and TNF are then thought to contribute tothe vacuolization and necrosis of keratinocytes as a secondary event. Erythema multiforme after radiotherapy with aromatase inhibitor administration in breast-conservation treatment for breast cancer.

The dense arrayof lymphocytes in the superficial dermis yields the elevated,flat-topped appearance of each papule or plaque. The chronicinflammatory reaction induces accentuation of the cornifiedlayer (hyperkeratosis) of the epidermis, which contributes tothe superficial whitish coloration perceived as Wickham striae.Although the many melanophages that accumulate in the papillary dermis hold a brownish black pigment, the fact that thepigmented cells are embedded in a colloidal matrix such asthe skin permits extensive scattering of light, a phenomenonknown as the Tyndall effect. She had stopped medicines after developing vesicles. Lichen planus affects both skin and mucous membranes. Papules are generally distributed bilaterally and symmetrically. The sites most commonly involved include the flexorsurfaces of the extremities, the genital skin, and the mucousmembranes. Rarely, lichen planus may involve the mucosa ofinternal organs, such as the esophagus.

Based on the clinical and histopathological findings, the animal was diagnosed with immune-mediated interface dermatitis and treatment with prednisolone (Vet-a-Mix, Lloyd Inc. This study was conducted at the Dicle University Faculty of Medicine and Diyarbakir Training and Research Hospital Dermatology clinics on patients diagnosed with erythema multiforme, either of the minor or the major subtype, from March 2012 to January 2013. Lichen Planus Papules Arrayed in an UnusualConfiguration—In these variants, typical individual papulesof lichen planus are grouped in a distinctive larger pattern.In annular lichen planus, small lichenoid papules coalesce toform a larger ring. Linear and zosteriform patterns of lichenplanus have also been observed. Ocular involvement in EM minor is rare. This variation has led to EM being divided into two overlapping subgroups (EM minor and Stevens-Johnson syndrome). Lichen Planus Papules with Unusual ClinicalMorphology—Some examples of lichen planus defy clinical recognition because the appearance of the individuallesions is atypical.

PATTERN; INTERFACE DERMATITIS
Erosive, vesiculobullous, atrophic, andhypertrophic lesions can be seen. In erosive lichen planus,the interface reaction that is directed against the epidermisis so profound that the entire epidermis becomes necroticand ulceration ensues. The closely related entity vesiculobul-lous lichen planus is also characterized by an intense interface reaction that yields necrosis of the epidermal junctionalzone across a broad front. As a result of basal layer necrosis,the epidermis becomes detached from its dermal attachments and a blister develops. In atrophic lichen planus, therate of destruction of keratinocytes by the lichenoid interface reaction exceeds the rate of epidermal regeneration, andthe epidermis becomes attenuated as a result. In contrast, inhypertrophic lichen planus, the rate of epidermal regeneration triggered by the interface reaction exceeds the rateof destruction, and thick, verrucous, hyperkeratotic lesionsdevelop. The pathogenesis of herpes-associated EM has been well studied and is consistent with a delayed-type hypersensitivity reaction [17,18].

Erythema multiforme is an acute cutaneous eruption that presents with a wide spectrum of clinical severity. The eruption is commonly brief and self-limited, but repetitive orgeneralized attacks can be disabling or even life threatening.As the name implies, variation in lesional morphology canbe seen, but most patients present with a monomorphouspattern in a given bout. The prototypical lesion is a red macule or thin papule that expands centrifugally and developsa dusky or necrotic center, creating a target-like pattern(Figure 8-14). Erythema multiforme is an uncommon but distinctive skin disease that afflicts men and women in nearly equal numbers. The peak incidence is in the second to fourth decadesof life, and onset during infancy or early childhood is a rarity. Like lichen planus, erythema multiforme represents acell-mediated immune reaction that eventuates in necrosis ofepidermal keratinocytes. Herpes simplex viral infection andreactions to medications have been established as the mostcommon causes of erythema multiforme.

Other known causesinclude Mycoplasma infection, contact dermatitis, drugs, andradiation. Erythema multiforme is a prototypical form of vacuolar interface dermatitis. In contrast to lichen planus, which typically presents with a dense obscuring lichenoid infiltrate within thesuperficial dermis, in erythema multiforme the inflammatoryinfiltrate is sparse. Thus, the vacuolated keratinocytes that arewidely distributed within the epidermal basal layer are conspicuous in the face of a sparse infiltrate, and the damagedkeratinocytes serve as the basis for the name of this pattern ofinflammatory skin disease. The most severe (and occasionally fatal) variant of the illness, in which the eyes, mouth, and internal organs are involved, is called Stevens-Johnson syndrome, or toxic epidermal necrolysis. There is amodest infiltrate of lymphocytes in the vicinity of the epidermal-dermal junction where vacuolated and necrotic keratinocytes areconspicuous. To vacuolated and necrotic keratinocytes.

Keratinocytes that are killed in the course of the inflammatory reaction becomeanucleate and are manifest microscopically as round, dense,eosinophilic bodies similar to the colloid bodies of lichen planus (Figure 8-15). i was down to 7 mls os steroids when it has just flared up again. After this recruitment, keratinocytes are injured and killed by the combined negativeinfluences of cytotoxicity and cytokines, such as interferon-yand TNF. Many cases of so-called erythema multiforme minor are triggered by herpes simplex viral infection. A relationshipbetween erythema multiforme and herpetic infection hadlong been suspected based on the documentation of precedingherpes simplex lesions in patients with erythema multiforme.The relationship was strengthened after antiherpetic drugtherapy, in the form of oral acyclovir, was shown to suppressthe development of erythema multiforme lesions in someindividuals. Molecular studies have substantiated the relationship by confirming the presence of herpes simplex DNAwithin skin from erythema multiforme lesions. HerpesvirusDNA is also demonstrable within peripheral blood lymphocytes and within lesional skin after resolution but not withinnonlesional skin.

These findings suggest that viral DNA is disseminated from the primary infection in the peripheral bloodand becomes integrated into the skin at specific target sites.The herpetic genomic fragments then contribute to the development of a cytotoxic effector response in their chosen targettissue, the skin. < 10% of the body surface area involved. At theperiphery of an erythema multiforme lesion, only sparseinflammation, slight edema, and subtle vacuolization of theepidermis are apparent in the outer erythematous halo. Incontrast, the dusky “bull’s eye” often shows pronounced epidermal vacuolization, with areas of near-complete epidermalnecrosis. Erythema multiforme is generally limited to the skin and mucous membranes. The lesions develop rapidly in cropsand are initially distributed on acral surfaces, although proximal spread to the trunk and face occurs not uncommonly.Mucosal erosions and ulcers are seen in roughly 25% of cases,and mucositis can be the sole presenting feature of the disease. Although erythema multiforme is an epithelial disorder,nonspecific constitutional symptoms such as malaise can alsooccur. Levels of IFN-γ were not different among the patients and the controls. The disorder is referred to as erythema multiforme minor when there are scattered lesionsconfined to the skin or when skin lesions are observed inassociation with limited mucosal involvement. A diagnosisof erythema multiforme major is based on the presence ofprominent involvement of at least two of three mucosal sites:oral, anogenital, or conjunctival. Many examples of erythemamultiforme major also display severe, widespread cutaneous involvement. Although Stevens-Johnson syndrome hadclassically been used to describe severe cases of erythemamultiforme, consensus classification has separated Stevens-Johnson syndrome from erythema multiforme and added itto the spectrum of toxic epidermal necrolysis. These two entities, Steven-Johnson syndrome and toxic epidermal necrolysis, are now considered to represent variant dermatologicmanifestations of severe idiosyncratic reactions. Most oftenthe result of medications, these entities involve vast regionsof skin and mucosal necrosis (Figure 8-16) with secondaryvesiculation. Pathologically, the findings are similar to thoseof a severe burn in that the integrity of a patient’s skin fails,resulting in an increased risk of infectious and metabolicsequelae.

You may also like