Contact sensitivity in otitis externa

Skin prick test reactivity in patients with chronic eczematous external otitis

Objectives

To investigate the incidence of skin prick test (SPT) positivity in patients with eczematous external otitis.

Methods

Forty-six patients with eczematous external otitis and forty-four healthy volunteers were included in the study. All the patients were skin-tested by prick test. Reactions were assessed by the degree of redness and swelling and the size of the wheal produced.

Results

According to SPT positivity and total immunoglobulin E values, the difference between the study and the control groups was statistically significant (P<0.05). The most common skin reactions were against to mites and grasses in this study.

Conclusion

Eczematous external otitis is perhaps the most difficult to treat of all forms of external otitis because the provocative agents usually remain undiagnosed. Patients suffering from eczematous external otitis symptoms should be investigated for allergens and be informed for prevention of the causative agents. SPT might be performed in cases of prolonged or treatment-resistant external otitis.

Allergic contact dermatitis to topical antibiotics: Epidemiology, responsible allergens, and management

Topical antibiotics are widely used to treat cutaneous, ocular, and otic infections. Allergic contact dermatitis to topical antibiotics is a rare but well-documented side effect, especially in at-risk populations. The purpose of this article is to review the epidemiology, responsible allergens, and management of allergic contact dermatitis to topical antibiotics.

LEARNING OBJECTIVE

After completing this learning activity, participants should be able to describe the epidemiology of allergic contact dermatitis related to topical antibiotics; show knowledge of the most common allergenic topical antibiotics; and understand the allergenic cross-reactivity pattern amongst topical antibiotics.

Hypersensitivity to topical corticosteroids in otitis externa

Over a12-monthperiod, nine patients were seen in a contact dermatitis clinic with an inflammatory dermatosis localized predominantly to the external auditory canal. Of these patients, four were found to have an allergic contact dermatitis which was exacerbating their dermatitis. All were allergic to one or more corticosteroids and topical antibiotics used in the treatment of their dermatitis. We would suggest that hypersensitivity to topical corticosteroids and other medicaments be considered in patients with otitis externa which fails to respond to treatment.