Understanding the dandruff flare-up: A cascade of measurable and perceptible changes to scalp health.

Summary

Switching from anti‑dandruff to non‑anti‑dandruff shampoo rapidly increased Malassezia load, barrier disruption, and inflammatory/oxidative biomarkers within 3 days, preceding visible flaking that rose around week 3. Self‑reported itch and flaking worsened in the switch group, whereas no objective deterioration occurred with continued anti‑dandruff use. Machine‑learning models linked inflammatory/oxidative markers and Malassezia to perceived scalp symptoms.

Key Findings

• Stopping anti‑dandruff shampoo increased Malassezia load, barrier disruption, and inflammatory/oxidative biomarkers within 3 days.
• Visible flaking (ASFS) rose around 3 weeks after switching, despite earlier biomarker changes.
• No objective worsening from baseline occurred in the continued anti‑dandruff group during 28 days.
• Self‑perceived itch and flaking worsened in the switch group; SMERF modeling linked biomarkers and Malassezia to perceived symptoms.

Clinical Implications

Advise regular, sustained use of anti‑dandruff treatments to maintain scalp barrier and prevent early inflammatory shifts that precede visible flaking. Biomarker panels (e.g., histamine, complement C3) and Malassezia load could serve as early endpoints in clinical testing and personalized scalp care.

Limitations

• Sample size not specified in the abstract and short (28‑day) follow‑up
• Industry formulation and generalizability to broader populations not fully addressed in the abstract

Future Directions

Validate early biomarker panels across larger, diverse cohorts; test intervention strategies timed to pre‑clinical biomarker shifts; expand multi‑omics to refine dandruff endotypes.