Contact urticaria from rifamycin

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.

Anaphylactic reaction to local administration of rifamycin SV

BACKGROUND AND OBJECTIVE

Systemic reactions during anesthesia are commonly attributed to muscle relaxants, hypnotics, macromolecular solutions, latex, or parenteral antibiotics. After exclusion of these different components as causes, we were interested in the potential implication of rifamycin in the systemic reaction, which occurred during anesthesia, and in the immunologic mechanism by which it can trigger this reaction.

METHODS

We report four cases of systemic reactions occurring after local administration of rifamycin. Three patients needed orthopedic surgery, and the fourth needed a urethrotomy. Severe systemic reactions occurred in all four patients when the surgeon washed the incision area with a rifamycin solution. All patients correctly responded to appropriate treatment and recovered. Skin tests were performed 2 months after the incident with the drugs used during anesthesia, latex, and rifamycin. To assess the relationship with a possible IgE-mediated mechanism, two in vitro tests were concomitantly performed to evaluate the cell reactivity to rifamycin: (1) determination of histamine release from peripheral basophils and (2) platelet cytotoxicity test, which explored the presence on platelets of specific IgE antibodies bound to the low-affinity receptor for IgE.

RESULTS

Skin tests were performed with different drugs used during surgery, and results were only positive for rifamycin in the four cases, accompanied in two cases by a systemic reaction. Histamine release from basophils was positive in three of four patients. The platelet cytotoxicity test results were positive in all four cases.

CONCLUSION

It appears that rifamycin, used locally during surgery, is apt to trigger severe systemic anaphylactic reactions, which are linked to an IgE-related process. This situation is worth pointing out, especially in patients who undergo repeated orthopedic operations during which, at least in Europe, rifamycin is commonly used for the prevention of local sepsis.

Contact urticaria and its mechanisms

This paper reviews the syndrome of contact urticaria in terms of current knowledge regarding pathophysiological mechanisms. The three mechanistic categories into which contact urticants are grouped include: (1) immunological contact urticaria, (2) non-immunological contact urticaria and (3) uncertain-mechanism-mediated contact urticaria. Within this schema, the clinical manifestations, diagnosis and therapy of contact urticaria are presented.