Challenge in Measuring Cutaneous Lupus Activity and Severity Save

JAMA Dermatology features a discussion by Drs. McMichael and Frey on measuring lupus skin disease in clinical trials and practice using the validated Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI).

The FDA has mandated that other inflammatory dermatologic diseases (acne, psoriasis, atopic dermatitis) develop and test similar outcome measures so as to develop new pharmaceuticals in those disorders. The CLASI was developed by Werth and colleagues in 2005, to objectively assess the activity of skin involvement for patients with cutaneous lupus erythematosus (CLE). 

The CLASI has 2 parts: CLASI-A, which measures disease activity, and CLASI-D, which evaluates disease damage.   Since that time Clinical trials in CLE have used these are primary outcome measures.

The CLASI is a clinical outcome measure specific to CLE. Before CLASI, patients with primary CLE without systemic lupus were underrepresented in trials. The CLASI-A score became crucial for determining trial eligibility; typically a CLASI-A score > 8 is often required for enrollment.

The CLASI evaluates 13 body regions according to Erythema, Scale, Dyspigmentation and Scarring (or Atrophy or Panniculitis). The CLASI-A score is largely driven by erythema - which may be more difficult in patients of color.  CLASI-A score asks investigators to classify the erythema as absent, pink, red, or dark red, purple, violaceous.

A current JAMA Dermatology examines lupus skin in 377 LE patients of mixed color and shows that chronic CLE was the most common subtype (64.5%) and discoid lupus (DLE) was the dominant form seen.  When erythema scores were compared, only the DLE subtype showed significantly lower scores among Black patients compared with White patients. Erythema was significantly more likely to be graded as pink in Black patients and as red in White patients.

The authors suggest that strong reliance on erythema as the dominant marker of disease activity CLE may not apply well to all skin types, especially darker skin. Other researchers have also noted the challeng of assessing skin with skin of darker tones. Also problematic is that lupus clinical trials are conducted by rheumatologists, not dermatologists. 

These reports underscore: A) the importance of the CLASI score in CLE clinical trials and reports and B) the need for care when assessing erythema in dark skinned patients. This becomes even more important as clinical trial efforts encouraging racial and ethnic diversity in dermatologic clinical trials.