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 5 features of scalp conditions (Dryness, Oiliness, Erythema, Folliculitis, and Dandruff) on a score of 0 to 3. To evaluate the validity of SPI, SPI grading was performed by 3 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.