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A Mouse Ear Model for Allergic Contact Dermatitis Evaluation
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Benzalkonium Chloride in Eye Drops Causing Allergic Contact Dermatitis: A Case Series
Arav Kannen1, Penelope Harrison1, Elizabeth Christou1,2
1Flinders Medical Centre, Adelaide, South Australia, Australia.
The Australasian Journal of Dermatology
|July 2, 2026
Summary
Allergic contact dermatitis (ACD) can occur from benzalkonium chloride (BAK), a common preservative in eye drops. This study examines BAK allergy, particularly in patients with atopic dermatitis or using dupilumab.
Area of Science:
- Ophthalmology
- Dermatology
- Allergology
Background:
- Benzalkonium chloride (BAK) is a widely used preservative in ophthalmic formulations.
- There is an increasing incidence of allergic contact dermatitis (ACD) linked to BAK in eye drops.
- Ocular surface irritation and sensitization are known properties of BAK.
Purpose of the Study:
- To report three cases of ACD caused by BAK in ophthalmic drops.
- To discuss the irritant and sensitizing effects of BAK on the ocular mucosa.
- To explore the prevalence and characteristics of BAK allergy in patients with atopic dermatitis and those treated with dupilumab.
Main Methods:
- Case report presentation of three patients diagnosed with ACD.
- Literature review on the properties of BAK in ophthalmic solutions.
- Analysis of patient history, focusing on atopic dermatitis and dupilumab use.
Main Results:
- Three patients developed ACD attributed to BAK in their prescribed eye drops.
- BAK's dual role as an irritant and sensitizer on the ocular surface is highlighted.
- The study identifies potential increased susceptibility in patients with atopic dermatitis or on dupilumab therapy.
Conclusions:
- Benzalkonium chloride in ophthalmic drops is a significant cause of ACD.
- Awareness of BAK allergy is crucial for ophthalmologists and dermatologists.
- Further investigation is warranted regarding BAK hypersensitivity in specific patient populations, including those with atopic dermatitis and dupilumab users.
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