The Last Refuge of Scoundrels

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Abstract
▪ Patriotism is the last refuge of a scoundrel. As all dermatopathologists know, the rendering of a specific diagnosis is an ideal, not easily accomplished in many cases. A "descriptive diagnosis" is one that states what the observer knows, and leaves to a comment or note speculation on what those findings might mean. A very common descriptive diagnosis is that of spongiotic dermatitis. The differential diagnosis of that pattern includes allergic contact and nummular dermatitis, the id reaction, dyshidrotic dermatitis, pityriasis rosea, erythema annulare centrifugum and other conditions too numerous to mention. Lost in many of our notes is the fact that in many cases, a specific diagnosis of one or another of the causes of the eruption will never be achieved, and the patient has, in the admittedly imprecise language of clinical dermatology, "eczema." Despite criticism of the term, most clinicians know what to do with a patient who has a spongiotic dermatitis that cannot be otherwise classified. A more difficult clinical situation occurs in the case of infiltrates of lymphocytes and eosinophils, sometimes joined by neutrophils within the dermis, as illustrated herein and on the cover (fig. 1). In many such cases, the dermatopathologist holds his or her nose, and uses a descriptive diagnosis such as "urticarial allergic eruption," or "urticarial hypersensitivity reaction." They then dutifully list urticaria, an urticarial drug eruption and an urticarial reaction to an arthropod assault as the most likely possibilities. Sophisticated dermatopathologists looks for adjunctive clues-a punctum, folliculocentricity* and extension of the infiltrate to involve the subcutis favoring an insect bite or sting, a predominance of neutrophils over eosinophils favoring urticaria, etc. Levels may reveal a scabietic mite or burrow, or show foci of spongiosis. The latter might point toward one of the spongiotic dermatitides with a disproportionately dense dermal infiltrate. Epidermal hyperplasia and hyperkeratosis, signs of rubbing, make idiopathic urticaria per se unlikely, as its lesions do not persist long enough to acquire these features. The infiltrates are often folliculocentric in reactions to bites or stings, Epidermal changes are often present in the cases that have been labeled as "itchy red bump disease" or "subacute prurigo."1 A partial list of adjunctive clues is displayed in Table 1. In addition to scrutiny of the histopathologic findings, a clinical history beyond what usually is scribbled onto a requisition is requisite to make sense of many of these cases. A recent review of this topic addressed integrating detailed clinical information into a final diagnosis.2 Other studies have noted leukemia and lymphoma in patients with urticarial papules resembling insect bites, and radiation therapy preceding urticarial lesions.3,4 This leaves many cases in which the dermatopathologists may label a condition as an urticarial reaction, but the clinical findings indicate that this is not remotely possible. I recall a middle aged African American woman presented at a regional dermatology conference who had a row of papules along the midline of the forehead, several centimeters long, with such a picture on biopsy. While I could not provide other than a descriptive diagnosis, there was not a clinician in the room who could offer a clinical diagnosis compatible with the histopathologic findings. What of the patient whose findings are displayed on the cover? Do they really have an insect bite reaction? The lesion that was sampled is in the axilla.

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