Quiz 24: What is your diagnosis?

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Diagnosis: Quiz 24

Quiz 24

Answer: Allergic contact dermatitis [complicated by the effects of persistent rubbing (lichen simplex chronicus) and vigorous scratching (excoriations)

Criteria for diagnosis histopathologically: The combination of a superficial perivascular infiltrate of lymphocytes admixed with eosinophils, a papillary dermis widened markedly by coarse bundles of collagen arrayed in vertical streaks, uneven psoriasiform hyperplasia, focal erosion, and scale-crust totals to a diagnosis of allergic contact dermatitis that has been rubbed and scratched.

Differential diagnosis histopathologically: Changes identical to these may be seen in nummular dermatitis that has been rubbed and scratched.

Criteria for diagnosis clinical: Dusky red plaques of peculiar geometric shape and with accentuation striking of skin markings, some of them interrupted by a fissure as well as with scales and hemorrhagic crusts, are those of allergic contact dermatitis on which has been imposed lichen simplex chronicus and evidences of excoriation.

Differential diagnosis clinically: Because these lesions clinical are so bizarre in outline, the possibility of their having been brought about entirely factitiously also must be considered. That, however, is excluded by virtue of the findings histopathologic, namely, eosinophils in large number and abundant serum in company with parakeratosis, the latter combination being an indication that the fundamental process is spongiotic (even though spongiosis no longer is visualizable in this section).

Clinicopathologic correlation: The plaque is formed by the constellation of infiltrates of inflammatory cells, an increase in amount of collagen in the papillary dermis, and by psoriasiform hyperplasia of the epidermis. The redness is secondary to dilation wide of venules in the upper part of the dermis, they, in vivo, having been crammed with erythrocytes. The scale-crust is made up of parakeratosis in company with serum. The lichen simplex chronicus is the result of both hyperplasia of the epidermis and of adnexal epithelial structures in conjunction with a papillary dermis widened by coarse bundles of collagen arranged in vertical streaks.

Options for therapy predicated on knowledge of histopathologic finding: The signs, indubitable, of lichen simplex chronicus cannot be reversed unless the patient ceases and desists from rubbing firmly the lesions. The same is true equally for the hemorrhagic crusts secondary to scratching; the latter must be interdicted if erosions are to be prevented. In addition to topical therapy with corticosteroid, it would be advisable to occlude the lesions with an Ace bandage in order to prevent the patient from wreaking further havoc on them. If that intervention is successful, lesions such as these could involute slowly over the course of months.

1) On grounds clinical alone, one can only speculate about the basic nature of these lesions. That they have been rubbed and scratched is a certainty, but whether those changes were inflicted on a primary pathologic process, such as allergic contact dermatitis, cannot be told with surety by inspection gross alone. Biopsy is essential to determining the essential character of this process, it, in actuality, being a spongiotic dermatitis.

2) The fact that there are loci in which parakeratosis envelops large amounts of serum bears testimony to the underlying process being one fundamentally spongiotic, even though at this very juncture frank spongiosis cannot be visualized. That is because, in time, the primary spongiotic process came to be psoriasiform and was complicated, in addition, by the effects of rubbing insistently and persistently for many months at least and scratching furiously episodically. In a lesion not fundamentally spongiotic, but that has been eroded secondary to scratching, there also may be serum in association with parakeratosis. In that situation, however, locules of serum are not encircled by parakeratosis. The locules of serum on the surface of an eroded lesion of a spongiotic dermatitis represent loci of spongiosis that have ascended and have become embraced by parakeratosis that resulted from an accelerated pace of epidermopoiesis secondary to the hyperplasia of epidermal keratocytes caught up in the primary pathologic process, e.g., allergic contact dermatitis and nummular dermatitis.

3) The lichen simplex chronicus seen clinically is explained histopathologically by epidermal and epithelial adnexal hyperplasia in conjunction with a papillary dermis widened by coarse bundles of collagen aligned parallel to one another and perpendicular to the skin surface. That combination of findings is diagnostic of lichen simplex chronicus. The signs clinical of scratching are erosions and scale-crusts. The fissures represent breaks in a compactly orthokeratotic stratum corneum, and such divides may penetrate the viable epidermis and extend into the papillary dermis.

4) It must be emphasized that although a spongiotic dermatitis and lichen simplex chronicus are present together in this section of tissue, the two processes are different distinctly and basically from one another. The spongiotic dermatitis came about because an allergen came into contact with the skin, whereas the lichen simplex chronicus resulted entirely from the effects of rubbing, hard and for long, the spongiotic dermatitis. So-called atopic dermatitis consists entirely of the effects of rubbing and scratching skin that is maddeningly pruritic (itching being a characteristic of the atopic state); no primary pathologic process, such as one spongiotic, is present in so-called atopic dermatitis. In short, atopic dermatitis is factitious, although a patient who creates it does have pruritic skin (pruritus being a symptom of the atopic state evidenced by the itchy nose, eyes, and palate of so-called allergic rhinitis).

5) We advise, for many reasons, that the term "eczema" (a favorite of dermatologists since the days of Hebra, who defined it, startlingly, as "that which looks like eczema") be abandoned, chief among those reasons being that it is altogether unnecessary. Each and every one of the "eczemas" can be diagnosed morphologically with specificity for what it is, e.g., nummular dermatitis, allergic contact dermatitis dyshidrotic dermatitis, id reaction, etc. But another indictment of "eczema" should be apparent in the two processes at play in the lesions depicted in this patient, namely, allergic contact dermatitis on one hand and lichen simplex chronicus plus excoriations on the other. It is now evident beyond doubt to readers of these lines that the first of those processes, i.e., the one spongiotic, was brought into being by an allergic contactant and the second by the dorsa of fingers (rubbing) and fingernails (scratching), not to exclude other implements oft- employed, such as a towel for rubbing or a knife, the better to "scratch" with. Despite the incontestable fact that the two processes are unrelated wholly to one another, clinically, histopathologically, etiologically, and pathogenetically, many textbooks of dermatology continue to contend that the spongiotic dermatitis of allergic contact dermatitis represents "acute eczema" and the lichen simplex chronicus represents "chronic eczema." That absurdity is explicable easily: to this day, there has not been a definition of "eczema" that is crisp, comprehensible, and agreed on. The consummate example of the opaqueness of the word is met with in the term "atopic eczema," which surely has nothing in common with the spongiotic vesicular dermatitides known as "classic" eczema, it being induced factitiously. Is it not long past due to cashier the word "eczema" and the notions flawed that prompted the introduction of it?

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