Measurement properties of the Rajka-Langeland severity score in children and adults with atopic dermatitis.

BACKGROUND

Multiple atopic dermatitis (AD) severity scales exist, with no gold standard for use in clinical practice.

OBJECTIVES

To determine the measurement properties of the Rajka-Langeland score and compare it with other clinician-reported outcomes in adults and children with AD.

METHODS

We performed a prospective dermatology practice-based study using questionnaires and evaluation by a dermatologist (n = 427).

RESULTS

Rajka-Langeland had good concurrent validity with the Eczema Area and Severity Index (Spearman rho = 0·63), SCORing AD (SCORAD) (rho = 0·61), objective-SCORAD (rho = 0·52) and body surface area (rho = 0·51); good convergent validity with the numeric rating scale average-itch (rho = 0·60) and worst-itch (rho = 0·59), Patient-Oriented Eczema Measure (rho = 0·57), Dermatology Life Quality Index (rho = 0·53), Patient-Reported Outcomes Measurement Information System Itch Questionnaire (rho = 0·35-0·55) in adults and/or children; fair discriminant validity for patient- and physician-reported global AD severity; good responsiveness to change of severity of AD and itch; good reliability; internal consistency; with no floor or ceiling effects. Interpretability bands (3, clear/almost clear; 4-5, mild; 6-7, moderate; 8-9, severe) and minimal clinically important difference (1 point) were established.

CONCLUSIONS

The Rajka-Langeland score showed good construct validity, reliability, internal consistency and responsiveness in adults and children with AD.