Allergic Contact Dermatitis and Topical Antibiotics

J. Desiree Douglas, MPA, PA-C


Dermatology Nursing 

In This Article


Neomycin is an antibiotic that belongs to the aminoglycoside family. It inhibits bacterial protein synthesis by irreversibly binding to the 30S ribosomal subunits. It is active against some aerobic gram-positive and multiple aerobic gram-negative bacteria (Gehrig & Warshaw, 2008). During patch testing, the proper concentration of neomycin is 20% in petrolatum (Marks, Elsner, & DeLeo, 2002).

Neomycin is the most commonly used topical antibiotic in the United States and in many European countries (Marks et al., 2002). It is available in both prescription and over-the-counter preparations. It fights infections of the skin, ears, and eyes. It is manufactured as creams, ointments, lotions, powders, and liquid preparations. Interestingly, neomycin-containing ointments seem to cause sensitization more often than creams, lotions, or powders (Rietschel & Fowler, 2008). Neomycin can be used alone or in combination with bacitracin, polymyxin, antifungals, and corticosteroids (Marks et al., 2002).

The first report of an allergy to neomycin occurred in 1952 (Gehrig & Warshaw, 2008). The frequency of neomycin allergies have ranged from 7.2%–13.1% in the past 20 years in patch test patients (Gehrig & Warshaw, 2008). To promote awareness, the American Contact Dermatitis Society (ACDS) recently named neomycin the 2010 Allergen of the Year (McNamara, 2010). Providers should be aware that neomycin can cause a late reaction, specifically after 3–4 days. Neomycin is used in a variety of products; therefore, providers need to prompt patients to disclose all prescription and over-the-counter medications used (Frosch, Menne, & Lepoitteven, 2006; McNamara, 2010).

The combination of impaired skin barriers with the prolonged use of topical antibiotics can increase the risk of developing allergic contact dermatitis (Gehrig & Warshaw, 2008). Therefore, the risk of ACD secondary to neomycin is increased when patients use neomycin on damaged skin such as atopic eczema, stasis dermatitis, lower leg ulcers, chronic venous insufficiency, chronic otitis externa, postoperative wounds, or posttraumatic wounds (Gehrig & Warshaw, 2008; Marks et al., 2002; Menezes De Padua et al., 2005).

After patients reach the age of 60 years old or more, they are 150% more likely to be allergic to neomycin (Gehrig & Warshaw, 2008). Another study showed 2.7% of patients less than 70 years old were allergic to neomycin, compared to 8.8% of patients greater than 70 years old (Green, Holden, & Gawkrodger, 2007). This may be due to the longer amount of time for possible exposure in a lifetime, and the frequent use of these types of products (Green et al., 2007). There have been no studies confirming a gender or race bias for neomycin allergies (Gehrig & Warshaw, 2008; Menezes De Padua et al., 2005).

Certain occupations can also have an increased risk of ACD due to antibiotic medications. Nurses, farmers, vet erinary surgeons, and pharmaceutical workers that handle antibiotics are among the high-risk groups (Gehrig & Warshaw, 2008). Workers at animal feed mills, and veterinary or health care workers can be at risk for a neomycin sensitivity (Frosch et al., 2006).

Neomycin sensitivity can manifest as an eczema-like localized reaction, contact urticaria, and rarely anaphylaxis (Marks et al., 2002). It may also present as delayed wound healing. It usually starts at the site of primary exposure but may spread to more distant sites, including id reactions (Gehrig & Warshaw, 2008).