Laboratory Studies
Hepatitis A, B, and C serologies are the most important tests because necrolytic acral erythema (NAE) has a high association with hepatitis C. Abdallah et al found that in 26 (87%) of 30 necrolytic acral erythema patients, recognition of the skin disease led to the initial diagnosis of hepatitis C virus infection. [3]
Assess liver function, including aspartate aminotransferase, alanine aminotransferase, bilirubin, protein, albumin, and alkaline phosphatase values. Some authors believe the lesions are most active during the active stage of hepatitis. The severity of the lesions does not correlate with the severity of the hepatitis.
Serum zinc, serum glucagon, and serum amino acid levels are low in some reported cases. Zinc deficiency and hyperzincuria was noted by Najarian et al. [29, 30]
Consider performing serum glucose and hemoglobin A1C tests because necrolytic acral erythema may be more common in persons with diabetes and hepatitis C.
Imaging Studies
CT scanning or MRI of the liver and pancreas can be considered as an ancillary assessment. In some reported cases, the pancreas was imaged, most likely because some believe necrolytic acral erythema (NAE) is a subset of necrolytic migratory erythema, a condition indicative of pancreatic glucagonoma. No pancreatic masses were found any of the patients imaged.
Procedures
Consider skin biopsy to substantiate the diagnosis of necrolytic acral erythema (NAE).
Histologic Findings
Necrolytic acral erythema (NAE) is perhaps best defined clinically rather than histologically. Bentley et al noted a case of necrolytic acral erythema without classic histology findings, which responded to oral zinc therapy. [31]
In 2004, Abdallah et al [26] noted the histopathological features described below.
Early stage - Nummular dermatitis–like moderate and regular acanthosis, as follows:
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Variable spongiosis
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Inflammatory infiltrate
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Pigment incontinence
Fully evolved stage - Psoriasiform epidermal hyperplasia, as follows:
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Marked papillomatosis
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Parakeratosis
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Focal hypergranulosis
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Pigment incontinence
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Occasional subcorneal pustules
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Epidermal pallor
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Vascular ectasia
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Infiltrate of inflammatory cells in the papillary dermis
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Necrotic keratinocytes - Sometimes become confluent in the upper epidermis, sometimes tracking along the acrosyringium
Late stage samples - Minimal-to-moderate acanthosis, as follows:
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Minimal-to-moderate inflammatory cell infiltrate
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Pigment incontinence
Others have noted epidermal necrosis with or without blister formation; vacuolar degeneration of the basal layer; and psoriatic changes with acanthosis, papillomatosis, hyperkeratosis, and parakeratosis. All of these are commonly found in persons in deficient nutritional states. Dermal findings have included a nonspecific superficial perivascular and interstitial lymphocytic dermatitis.
El-Ghandour et al [21] noted that electron microscope examination of patients with necrolytic acral erythema demonstrated clumped tonofilaments in the keratinocytes, yet hepatitis C virus RNA could not be detected in the plaques of necrolytic acral erythema.
Staging
Some have attempted to stage necrolytic acral erythema (NAE) with the following [32] :
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Stage 1: Erythematous papules or plaque without with scale; dusky or eroded center; histological findings of nummular eczema–range of spongiosis, variable inflammatory infiltrate, and pigmentary incontinence
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Stage 2: Papular or plaque confluence, sharp borders, thick adherent scale, less redness, more pigmentation; lichenification and pustules are variants; histological findings of parakeratosis, marked papillomatosis, pigment incontinence, rare subcorneal pustules, focal hypergranulosis, vascular ectasia, papillary dermis, variable inflammatory cell infiltrate, epidermal pallor, occasional acrosyringium tracking, necrotic keratinocytes, and a confluence of findings
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Stage 3: Plaques usually thin, hyperpigmentation remains demarcated, chronic clearing and reoccurrence; histological findings of pigmentary incontinence and moderate-to-mild inflammatory cell infiltrate
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Plaque of necrolytic acral erythema on the ankle of a male.
