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August 1992

Exogenous Origin of n-Alkanes in Pathologic Scale

Author Affiliations

From the Dermatology Service, Veterans Affairs Medical Center, Departments of Dermatology and Pediatrics, University of California San Francisco (Drs Williams, Ghadially, and Elias, and Ms Brown); and the Center for Accelerator Mass Spectrometry, University of California, Lawrence Livermore National Laboratory, Livermore (Dr Vogel).

Arch Dermatol. 1992;128(8):1065-1071. doi:10.1001/archderm.1992.01680180059006

• Background.—  Although n-alkanes accumulate in some disorders of cornification, recent studies using radioactive carbon 14 content by accelerator mass spectrometry point to an exogenous origin for alkanes in normal stratum corneum, and their derivation in congenital ichthyosiform erythroderma remains controversial.

Design and Results.—  Using 14C content to measure sample age, the n-alkane fractions from two patients with congenital ichthyosiform erythroderma contained no detectable contemporary materials. By electron microscopy, alkane-enriched emollients (petrolatum [Vaseline]) permeated to all levels of stratum corneum of hairless mice, expanding the intercellular domains and distorting membrane bilayers. Similar ultrastructural changes were also observed in the stratum corneum of patients with congenital ichthyosiform erythroderma. When alkanes were excluded, no differences in lipid content were evident between two forms of autosomal recessive ichthyosis.

Conclusions.—  These data demonstrate that scale n-alkanes in disorders of cornification derive from environmental sources and indicate the pervasiveness of petroleum-based emollients in skin. Therefore, epidermal lipid analyses must be interpreted with caution. However, these studies do not rule out an important therapeutic and/or pathogenic role for exogenous n-alkanes in skin.(Arch Dermatol. 1992;128:1065-1071)

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