Exploring the safety and effectiveness of subcutaneous autologous serum therapy versus conventional intramuscular autologous serum therapy in chronic urticaria: An observer-blind, randomized, controlled study.

BACKGROUND

Autologous serum therapy aims to supplement the existing pharmacotherapy in chronic urticaria by decreasing the antihistamine pill-burden and maintaining symptom-free interval. Subcutaneous autologous serum therapy further modifies the amount of serum (2 mL to 1 mL) and gauge of a needle (24G to 31G) to improve compliance and facilitate ease of application.

OBJECTIVES

To assess clinical effectiveness and safety of subcutaneous autologous serum therapy versus conventional intramuscular autologous serum therapy and to compare the quality of life in the two treatment arms.

METHODS

Institution-based, assessor-blind, prospective, randomized, parallel-group, active-controlled trial with 32 patients in each treatment arm and analyzed on a modified intention to treat principle. After baseline autologous serum skin test, autologous serum was injected as per randomization every week for 9 consecutive weeks.

RESULTS

Among the study population, conventional intramuscular autologous serum therapy and subcutaneous autologous serum therapy had a comparable duration of disease (P = 0.164, Mann-Whitney U test), autoreactive status (P = 0.796), urticaria total severity score (P = 0.637) and urticaria activity score summed up over 7 days (P = 0.982). Both urticaria activity score summed up over 7 days and total severity score along with antihistamine pill-burden reduced significantly (P < 0.001, Friedman's analysis of variance) in both subcutaneous autologous serum therapy and conventional intramuscular autologous serum therapy from first follow-up onwards (P < 0.05, Post hoc Dunn's test). Significant improvement was noted in patient's as well as physician's global assessment of disease activity improvement scale (P < 0.001, Friedman's analysis of variance). Intergroup analysis showed that there was no significant difference in urticaria activity score summed up over 7 days either at baseline (P = 0.982, Mann-Whitney U test) or at study end (P = 0.398, Mann-Whitney U test). Similar comparable results were found in the total severity score at the end of the study (P = 0.345, Mann-Whitney U test). Dermatology life quality index showed marked improvement with both types of treatment (P < 0.0001, Wilcoxon test), and the intergroup comparison showed comparable dermatology life quality index values (P = 0.994, Mann-Whitney U test). The pain score at the injection site was more with conventional intramuscular autologous serum therapy than subcutaneous autologous serum therapy (P = 0.0115, Mann-Whitney test). Younger age and lower baseline total severity scores were associated with a better therapeutic response. Baseline urticaria activity score added up over a period of 7 days and total severity scores and the diameter of lesions showed a positive correlation with response pattern.

LIMITATION

Basophil histamine release assay not done. Logistics could not support follow-up beyond the end of treatment.

CONCLUSION

Subcutaneous autologous serum therapy is not inferior to conventional intramuscular autologous serum therapy with the additional advantage of less pain and operational feasibility.