Studies addressing the characteristics of acne induced post inflammatory hyperpigmentation (PIH) including, prevalence, associated features or the impact are scarce. No formal grading system has been tested on patients from the subcontinent.
We embarked on describing features of acne related pigmentation and testing a new instrument, postacne hyperpigmentation index (PAHPI), on Sri Lankan patients with acne induced PIH.
All patients (n=73) who presented with acne and or any complication(s) of acne within a period of a month, to skin clinic of a District General Hospital and the aesthetic clinic of a tertiary care private Hospital were entered into the study. Each patient was interviewed and examined by an experienced consultant and a trained medical officer. The expert clinically graded the acne severity and both scored independently, using the PAHPI. Various other associated factors were recorded.
Sixty nine (94.5%) patients had some degree of pigmentation; thirty eight (52%) had moderate and severe pigmentation on clinical grading. Majority of the participants found pigmentation to be equal to or more troublesome than acne itself. (60%) Highly significant correlation was seen between the scores given, using the PAHPI by expert and the trainee. [r=0.8; P<0.01] Furthermore, high degree of inter-rater agreement (between expert and trainee) was observed comparing the categories -mild/moderate/severe- using the PAHPI. [Kappa = 0.615]. Correlation between global severity rank (clinical grading) and PAHPI rank by the Consultant was moderately high. [Kappa = 0.557].
PAHI is a reliable tool to grade severity of acne induced hyperpigmentation which is a very common and a troublesome sequel among our patients.