<\/span><\/h2>\nEczema<\/span> It is a common skin condition with multiple clinical patterns, characterized histologically<\/span> for spongy<\/span> tissue reaction pattern. The terms eczema and dermatitis<\/span> are often used interchangeably to denote a polymorphic<\/span> inflammatory<\/span> reaction pattern involving the epidermis<\/span> and dermis<\/span>. However, 'dermatitis' means inflammation<\/span> of the skin and is not synonymous with eczematous<\/span> processes. The consensus among most dermatopathologists is that the term 'eczema' should be replaced by the term 'spongiotic dermatitis' to reflect the histopathological changes underlying the so-called 'eczema'.<\/p>\n<\/span>\nHistology<\/span> eczema<\/span><\/h2>\nThe spongiotic tissue reaction pattern is characterized by intercellular. edema<\/span> inside the epidermisspongiosis<\/span>) Initially, there is an enlargement of the intercellular spaces between keratinocytes<\/span> and lengthening of intercellular bridges. Increased accumulation of fluid leads to the formation of intraepidermal<\/span> vesicles<\/span>. Spongiotic dermatitis is a dynamic disease process; vesicles come and go and can be located at different levels of the epidermis. Infiltration<\/span> of the epidermis with lymphocytes<\/span> (exocytosis<\/span>) It is common. Parakeratosis<\/span> it forms above the areas of spongiosis, probably as a result of an acceleration in the movement of keratinocytes towards the surface. Drops plasma<\/span> accumulate in the mounds of parakeratosis. Dermal<\/span> changes include varying degrees of edema and a superficial effect perivascular<\/span> infiltrate<\/span> with lymphocytes, histiocytes<\/span> and occasional neutrophils<\/span><\/span> and eosinophils<\/span>.<\/p>\n\n
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<\/span>Three stages of eczema.<\/span><\/h2>\nClinically, eczema is grouped<\/span> according to etiology<\/span>. Histologically, it is more useful to classify eczema according to chronicity<\/span>. Histologically, there are three stages of eczema: acute<\/span>, subacute and chronic<\/span>. An eczematous disease can start at any stage and progress to another.<\/p>\n<\/span>Acute eczema<\/span><\/h3>\nAcute spongiosis is characterized by massive intercellular edema of the epidermis with widening of the intercellular spaces, disruption of desmosomes<\/span> and microvesicle formation. Although vesicles are usually intraepidermal, with sufficient vesiculation, they can become subepidermal. The vesicles are filled with protein fluid containing lymphocytes and histiocytes (Figure 1, arrow). In allergic \/ contact dermatitis, eosinophils may be prominent (eosinophilic<\/span> spongiosis).<\/p>\n<\/span>Subacute eczema<\/span><\/h3>\nThis is the most common type of spongiotic dermatitis. The degree of spongiosis and exocytosis of inflammatory cells is mild to moderate. Irregular acanthosis<\/span> and parakeratosis are additional features compared to acute spongiotic dermatitis. A superficial dermal perivascular lymphohistiocytic<\/span> inflammatory infiltrate, swelling of endothelial<\/span> papillary dermal edema and cells are present (Figure 2).<\/p>\n<\/span>Chronic eczema<\/span><\/h3>\nIn chronic spongiotic dermatitis, the degree of spongiosis is often mild and difficult to appreciate. Vesiculation is rare. There is significant epidermal<\/span> acanthosis, which can show a psoriasiform<\/span><\/span> pattern with hyperkeratosis<\/span>, hypergranulosis<\/span> and minimal parakeratosis. Fibrosis<\/span> of the papillary dermis<\/span> may be present (figure 3).<\/p>\n\n<\/span>Eczema pathology<\/span><\/h5>\n<\/section>\n\n\n
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Figure 1<\/p>\n
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Figure 2<\/p>\n
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figure 3<\/p>\n<\/p><\/div>\n<\/section>\n
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<\/span>Types of eczema<\/span><\/h2>\n<\/span>\nAtopic<\/span> dermatitis<\/span><\/h3>\nAtopic dermatitis is a common skin condition, particularly in children, and is associated with a personal and family history of atopy<\/span>. Although acute and subacute spongiotic patterns have been described in atopic dermatitis, they are much less common than chronic spongiosis. Interestingly, a follicular<\/span> not uncommon pattern showing spongiosis of the infundibular<\/span> A portion of follicles<\/span> and a scarce dermal infiltrate (figure 4, the arrow shows follicular spongiosis). The follicular pattern is more often found in more depth pigmented<\/span> cutaneous<\/span> phototypes<\/p>\n<\/span>\nIrritating<\/span> contact dermatitis<\/span><\/h3>\nIrritant contact dermatitis is caused by contact with water, detergents, and other chemicals, and subsequently occurs more frequently on the hands. The histology of irritant contact dermatitis is typically mild spongiosis, epidermal cells. necrosis<\/span>and neutrophilic<\/span> infiltration of the epidermis. Figure 5 shows an early injury<\/span> with infiltration of the epidermis by neutrophils. Figure 6 shows a more acute and severe example with full thickness necrosis.<\/p>\n<\/span>Allergic contact dermatitis<\/span><\/h3>\nAllergic contact dermatitis occurs when there is sensitization<\/span> to a generally tolerated environmental contact such as nickel, fragrance, hair<\/span> dye or preservatives. A pattern of subacute, chronic, or acute dermatitis can be seen. The dermal inflammatory infiltrate contains predominantly lymphocytes and other mononuclear cells (Figure 7). Allergic contact dermatitis occasionally causes atypical<\/span> T cell<\/span> infiltrators<\/span> which can simulate mycosis fungoides.<\/p>\n\n<\/span>Contact eczema pathology<\/span><\/h5>\n<\/section>\n\n\n
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Figure 4<\/p>\n
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Figure 5<\/p>\n
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Figure 6<\/p>\n
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Figure 7<\/p>\n<\/p><\/div>\n<\/section>\n
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<\/span>\nDiscoid<\/span> eczema<\/span><\/h3>\nDiscoid eczema or nummular dermatitis is a particularly chronic eczema characterized clinically by papules<\/span> or papulovesicles<\/span> which get together<\/span> in coin-shaped patches. Histological<\/span> Changes vary with chronicity. Early lesions show moderate spongiosis with mild acanthosis and exocytosis of inflammatory cells. Over time, the degree of acanthosis increases. Additional features include scale<\/span>–Cortex<\/span> formation over the thickened epidermis and dermal perivascular inflammatory infiltrate. Usually it is wise to make special stains to exclude a fungus infection<\/span> (tinea corporis)<\/p>\n<\/span>Stasis dermatitis<\/span><\/h3>\nStasis dermatitis is a common condition that affects the secondary legs of people with disabilities. venous<\/span> circulation. Spongiosis is usually mild with foci of parakeratosis and scaly crusts. Ulceration<\/span> It is a common complication. Dermal changes are prominent with neovascularization, hemosmosin<\/span> statement<\/span> and varying degrees of fibrosis (depending on chronicity).<\/p>\n<\/span>\nSeborrheic<\/span> dermatitis<\/span><\/h3>\nSeborrheic dermatitis occurs most frequently on the scalp and face secondary to toxic<\/span> Yeast produced substances. Histologically there is a spongiosis that can be acute, subacute or chronic depending on the biopsy of the lesion. Spongiosis may have an overlying bark area and is often found on hair. follicle<\/span> (figure 8). Presence of neutrophils within the epidermis or stratum corneum<\/span> should provoke further examination of yeast with PAS staining. More chronic injuries show progressive<\/span> psoriasiform hyperplasia<\/span> of the epidermis with less spongiosis. Dermal changes include mild edema of the papillary dermis with a mild superficial perivascular infiltrate of lymphocytes, histiocytes, and neutrophils.<\/p>\n<\/span>Asteatotic eczema<\/span><\/h3>\nAsteototic eczema develops as a result of very dry skin. It is more common in the elderly and in the lower extremities. Histologically, the most common finding is mild subacute spongiotic dermatitis. The stratum corneum is compact and slightly irregular (Figure 9).<\/p>\n
<\/span>Go reaction<\/span><\/h3>\nId reaction or autoeczematisation describes the appearance of generalized<\/span> eczema in response to a located<\/span> skin disease<\/span> or infection at a distant site. Clinically the reaction of Id is polymorphous<\/span> including pompholyx-like reactions affecting the hands and feet or more generalized papular<\/span> rashes<\/span>. The histology of the id reaction often mimics that of initially localized dermatosis or shows a spongiotic reaction pattern with varying intensity. Mild dermal edema and lymphocytic<\/span> infiltrations are reported.<\/p>\n<\/span>Lichen simplex<\/span><\/h3>\nLichen simplex is a type of neurodermatitis characterized by areas of thickening of the skin in response to repeated scratching or rubbing. Histologically, there is marked hyperkeratosis, hypergranulosis, and occasional small foci of parakeratosis. The epidermal ridges are elongated and irregularly thickened. Mild spongiosis is variably present depending on the cause. Papillary dermal fibrosis is a characteristic feature (Figure 10).<\/p>\n
<\/span>\nNodular<\/span> prurigo<\/span>
\n<\/span><\/h3>\nPrurigo nodularis is a severe itchy skin condition of unknown etiology, characterized by firm, itchy bumps. Histologically, there is an increase in acanthosis compared to lichen simplex, orthohyperkeratosis, and hypergranulosis. The areas of acanthosis and dilated follicles form a discreet<\/span> mass that can be seen histologically (Figure 11). Mild spongiosis and parakeratosis are occasional features. Lesions often erode as a result of excoriation<\/span>, and there may be minor changes marked to mimic a scaly<\/span> carcinoma<\/span>. Dermal changes include