SCCA2 as a biomarker reflecting patient-reported disease burden in children with mild atopic dermatitis under maintenance therapy.

BACKGROUND

In mild atopic dermatitis (AD), evaluating disease activity during maintenance therapy is challenging due to subtle clinical signs. Serum squamous cell carcinoma antigen 2 (SCCA2) has been proposed as a sensitive biomarker, but its utility in assessing disease status specifically in mild AD remains unclear.

OBJECTIVE

To assess the utility of serum SCCA2 in children with mild AD receiving maintenance therapy, focusing on its relationship with patient-reported outcomes. Serum thymus and activation-regulated chemokine (TARC), an established marker, was analyzed as a comparator.

METHODS

Sixty-nine pediatric patients with mild AD were enrolled. Clinical severity was assessed by the Eczema Area and Severity Index (EASI; physician-rated) and the Patient-Oriented Eczema Measure (POEM; patient-reported). Baseline serum SCCA2 and TARC were measured. Associations were first examined using Spearman's rank correlation. Temporal associations between baseline SCCA2 and POEM at Days 3 and 7 were further evaluated using linear mixed-effects models, and complementary bootstrap resampling and Steiger's Z test were applied for correlation comparisons.

RESULTS

Although all patients were classified as mild by EASI, POEM scores ranged widely, indicating discordance between physician- and patient-assessed severity. SCCA2, but not TARC, was significantly correlated with POEM scores at baseline. The correlation between baseline SCCA2 and POEM was strongest on Day 3 and attenuated by Day 7. Linear mixed-effects modeling confirmed a significant time-dependent association.

CONCLUSION

SCCA2 reflects patient-experienced symptom burden more closely than physician-assessed severity in mild AD. Its short-term, time-dependent association with POEM suggests potential utility for identifying early or imminent symptom burden.