Role of linoleic acid in arsenical palmar keratosis

Chronic arsenic exposure can lead to palmoplantar keratosis. In the stratum corneum of skin, linoleic acid is of the utmost importance to the inflammation, keratinization, and regeneration processes.

The aims of this study were: (i) to present quantitative information on the linoleic acid fraction of intercorneocyte lipids, and (ii) to elucidate the role of linoleic acid in the pathophysiology of arsenical keratosis.

Lipid extracts were collected from keratotic lesions in seven patients, seven arsenic-exposed subjects, and seven non-exposed control subjects. Linoleic acid levels of the specimens were estimated by reverse-phase high-performance liquid chromatography (RP-HPLC).

There was a significant (P < 0.001) increase in mean ± standard error (SE) linoleic acid levels in arsenical keratosis patients (palm: 25.66 ± 4.95 μg/cm(2); dorsum: 28.25 ± 6.20 μg/cm(2)) compared with arsenic-exposed (palm: 2.75 ± 0.85 μg/cm(2); dorsum: 1.96 ± 0.64 μg/cm(2)) and non-exposed (palm: 1.52 ± 0.61 μg/cm(2); dorsum: 1.28 ± 0.39 μg/cm(2)) control subjects. There was no significant difference (P = 0.556) in linoleic acid concentration in the non-affected skin of the dorsum of the hand (28.25 ± 6.20 μg/cm(2)) compared with that in the palmar sites (25.66 ± 4.95 μg/cm(2)) in the patient group. The change in linoleic acid levels in the arsenic-exposed control group did not differ from that in non-exposed controls (P = 1.000).

Linoleic acid concentration is elevated in arsenical keratosis; this finding warrants further investigation to ascertain whether linoleic acid plays a direct role in the pathophysiology of arsenical keratosis.