Understanding Neomycin-Induced Contact Allergy

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Neomycin plays a crucial role in infection control due to its broad-spectrum antimicrobial activity. However, its allergenic potential has been increasingly documented, raising concerns about its widespread use.¹ While antibiotic resistance remains a critical issue in antimicrobial stewardship, the prevalence of contact allergy to antibiotics such as neomycin is a significant but less-explored topic.² Recent research synthesizes existing literature to estimate CA prevalence in adults and children and evaluates trends over time and across regions.³

“CA to neomycin is frequent in both adults and children throughout the study period. However, the prevalence varies significantly according to geographical regions. We recommend a withdrawal of neomycin in regions still utilizing it or limiting over-the-counter sale with legislation requiring a prescription to buy neomycin medication,” researchers wrote.

Methods

A systematic review was conducted following PRISMA guidelines. Studies were identified using PubMed, Embase, and Web of Science with specific search strategies. Inclusion criteria required original studies in English with at least 100 consecutively patch-tested participants who had dermatitis and underwent testing with neomycin. Studies focusing on specific anatomical sites or general population samples were excluded. Statistical analyses were performed using random-effects models to estimate pooled prevalence rates with 95% confidence intervals (CIs).

Results

A total of 70 studies met inclusion criteria, comprising 52 studies on adults and 18 studies on children. Among adults, 456,372 individuals were analyzed, with 14,590 positive patch test results, yielding a pooled prevalence of 3.2% (95% CI, 2.6% to 3.8%). Among children, 17,720 individuals were included, with 708 positive cases, resulting in a pooled prevalence of 4.3% (95% CI, 2.6% to 6.3%).

Geographical Variation

Researchers stated significant regional differences were observed. The highest prevalence in adults was noted in North America (6.4%) and South America (6.2%), while Europe exhibited a lower prevalence (2.5%). In children, North America showed the highest prevalence (8.1%), whereas Europe reported a notably lower rate (0.8%). These variations may be attributed to differences in antibiotic prescribing patterns, vaccine formulations, and genetic predispositions.

Trends Over Time

Analysis of studies before and after 2000 revealed a decline in adult CA prevalence (from 5.2% to 2.1%), whereas prevalence in children increased (from 2.0% to 5.1%). This shift suggests changes in neomycin exposure, particularly through vaccines and other pharmaceutical formulations.

“With sensitization rates for children in this study exceeding 8% in North America, and for adults being 6.4% in North America, 5.3% in Southeast Asia, and 4.9% in South Asia, there is an immediacy call for better regulation on neomycin medical products in these regions<” the study stated.

Discussion

The overall prevalence of neomycin-induced CA in this study aligns with known allergens such as fragrance mix I (7%) and preservatives like methylisothiazolinone (5%). The study stated the increasing prevalence in children raises concerns about early-life sensitization, potentially due to exposure through vaccines and pediatric medications. The declining prevalence in adults may be linked to reduced topical antibiotic use and changes in prescribing practices. Researchers suggested further research is necessary to elucidate the impact of regulatory policies and patient education on these trends.

Conclusion

The study found that neomycin remains a significant contact allergen, particularly in North America and South Asia. Its presence in common pharmaceutical products necessitates heightened awareness among healthcare providers. Given the observed increase in pediatric cases, further investigations into exposure sources and preventive measures are warranted. Clinicians should consider alternative treatment options for patients with known sensitivities to minimize allergic reactions and optimize patient care.

References

1. Menezes de Pádua CA, Schnuch A, Lessmann H, Geier J, Pfahlberg A, Uter W. Contact allergy to neomycin sulfate: results of a multifactorial analysis. Pharmacoepidemiol Drug Saf. 2005;14(10):725-733. doi:10.1002/pds.1117
2. Wilkinson SM, Gonçalo M, Aerts O, et al. The European baseline series and recommended additions: 2023. Contact Dermatitis. 2023;88(2):87-92. doi:10.1111/cod.14255
3. Jensen MB, Isufi D, Larsen CK, Schwensen JFB, Alinaghi F, Johansen JD. Prevalence of contact allergy to neomycin in dermatitis patients: A systematic review and meta-analysis. Contact Dermatitis. 2025. Doi:10.1111/cod.14784