Acrodermatitis Enteropathica Workup

Updated: Aug 21, 2019
  • Author: Kristina Marie Dela Rosa, MD; Chief Editor: William D James, MD  more...
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Workup

Laboratory Studies

Plasma zinc levels should be tested. Specimens should be collected in plastic syringes or acid-washed Vacutainer tubes with no rubber stopper to prevent exogenous contamination that could lead to spuriously normal measurements. Plasma zinc concentrations of less than 50 mcg/dL are suggestive, but not diagnostic, of acrodermatitis enteropathica. [9]

Hair, saliva, or urine zinc levels can be obtained but are rarely needed. [25]

Because alkaline phosphatase is a zinc-dependent enzyme, reduced serum levels of alkaline phosphatase in the context of normal zinc levels can indicate a zinc deficiency. [26] However, alkaline phosphatase levels are typically not decreased unless the individual has advanced disease.

Analysis of maternal breast milk zinc concentrations may help in differentiating acrodermatitis enteropathica from acquired zinc deficiency. [1]

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Histologic Findings

Light microscopy

Histological evaluation of a skin biopsy specimen is characteristic, but the same findings can be seen in other nutritional disorders. The histological findings vary with the age of the lesion. Early lesions show confluent parakeratosis associated with a reduced granular layer. Often, exocytosis of neutrophils into the epidermis is noted, which may be acanthotic and exhibit slight spongiosis. The intracellular edema eventuates into pallor of the upper third of the epidermis. [27] Subsequently, subcorneal and intraepidermal clefts may develop as a result of massive ballooning and reticular degeneration, with necrosis of the keratinocytes. [28] In late lesions, psoriasiform hyperplasia of the epidermis and less epidermal pallor are noted. [29]

Electron microscopy

Extracellular edema is associated with degenerate keratinocytes with multiple cytoplasmic vacuoles and slender, fingerlike protrusions. Few desmosomes are present, and the basal lamina is well preserved. Additionally, accumulation of cytoplasmic lipid droplets and intracellular edema in the spinous layer of the epidermis are seen. [30]

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