Development of a new classification and scoring system for scalp conditions: Scalp Photographic Index (SPI)

Background and objectives There has been no validated tool for objectively quantifying the overall condition and characteristics of the scalp. This study aimed to establish and validate a new classification and scoring system for evaluating scalp conditions.Methods The Scalp Photographic Index (SPI) using a trichoscope grades five features of scalp conditions (dryness, oiliness, erythema, folliculitis, and dandruff) on a score of 0–3. To evaluate the validity of SPI, SPI grading was performed by three experts on the scalps of 100 subjects along with a dermatologist’s assessment of the scalps and a scalp-related symptom survey. For reliability assessment, 20 healthcare providers performed SPI grading for the 95 selected photographs of the scalp.Results SPI grading and the dermatologist’s scalp assessment showed good correlations for all five scalp features. Warmth showed a significant correlation with all features of SPI and the subjects’ perception of a scalp pimple had a significant positive correlation with the folliculitis feature. SPI grading demonstrated good reliability with excellent internal consistency (Cronbach’s α = 0.90) and strong inter- and intra-rater reliability (Kendall’s W = 0.84, ICC(3,1)=0.94).Conclusions SPI is an objective, reproducible, and validated numeric system for classifying and scoring scalp conditions.