Post-inflammatory hyperpigmentation (PIH) may affect any skin type but has been linked to darker skin types.

A new study published in the Journal of Cosmetic Dermatology aimed to validate the reliable use of a Palmar Creases Pigmentation (PCP) scale, and its accuracy in predicting the risk of PIH.

This prospective, comparative, blinded study, photo-numeric analysis of 126 photographs of pairs of palms, utilized a 4-point visual scale based on the level of contrast between palmar crease pigment and that of the surrounding skin. Score 0 indicated no difference; score 1 referred to a low difference; score 2 meant a moderate difference; and score 3 related to a high difference.

The findings revealed a significant degree of inter-rater reliability at both evaluation visits, with an intraclass correlation coefficient (ICC) = 0.908, at the first evaluation and an ICC = 0.924, at the second evaluation—demonstrating a validity of the scale. Meanwhile, Global Fleiss kappa for intra-rater reliability for all physicians was 0.514.

Thus, it was inferred that the PCP scale can be effectively used by any physician to predict the hyperpigmentation risk.

Source: Journal of Cosmetic Dermatology. 2021 Feb 2. doi: 10.1111/jocd.13968.