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Exogenous origin of n-alkanes in pathologic scale.
M L Williams1, J S Vogel, R Ghadially
1Dermatology Service, Veterans Affairs Medical Center, San Francisco, CA 94121.
Archives of Dermatology
|August 1, 1992
Summary
n-alkanes found on skin scales originate from environmental sources, not internal production, particularly petroleum-based emollients. This finding impacts how skin lipid disorders are understood and treated.
Area of Science:
- Dermatology
- Biochemistry
- Biophysics
Background:
- n-alkanes accumulate in some skin disorders.
- Previous studies suggested exogenous origins for alkanes in normal skin.
- The source of alkanes in congenital ichthyosiform erythroderma was debated.
Purpose of the Study:
- To investigate the origin of n-alkanes in congenital ichthyosiform erythroderma.
- To examine the effect of alkane-enriched emollients on skin structure.
- To clarify the role of environmental alkanes in skin barrier function.
Main Methods:
- Radiocarbon dating (Carbon-14 content) of n-alkanes.
- Electron microscopy of skin samples from mice and patients.
- Lipid content analysis excluding alkanes.
Main Results:
- n-alkane fractions from patients lacked contemporary carbon, indicating an environmental origin.
- Alkane-enriched emollients (petrolatum) penetrated mouse stratum corneum, altering intercellular domains and membrane bilayers.
- Similar ultrastructural changes were observed in patients with congenital ichthyosiform erythroderma.
- Excluding alkanes revealed no lipid differences between two forms of autosomal recessive ichthyosis.
Conclusions:
- Scale n-alkanes in disorders of cornification originate from environmental sources, notably petroleum-based emollients.
- Epidermal lipid analyses require careful interpretation due to pervasive exogenous alkanes.
- The therapeutic or pathogenic role of exogenous n-alkanes in skin warrants further investigation.