Adverse cutaneous reactions to soft tissue fillers--a review of the histological features.

The enhanced use of exogenous substances for cosmetic and reconstructive procedures is paralleled by an increase in reports of cutaneous adverse reactions to several of these agents. Recognition of the histological features of these reactions is of importance to both dermatologists and dermatopathologists but is not always easy for several reasons. First, cost-related issues are resulting in an increasing number of these procedures being performed overseas. Thus, patients are often unsure about the exact product used. Compounding this is the fact that practitioners who perform these procedures are not forthright in divulging this information, given that improper substances may be admixed in the filler injected. Furthermore, cutaneous reactions may occur at sites distant from injected sites, secondary to migration of the filler substance and a lapse of months to years may occur prior to the development of a cutaneous reaction. Thus, a causal relationship between the procedure and the reaction is often not made. We present an overview of the histological features of adverse reactions to currently available soft tissue fillers, both in the United States and overseas, in an attempt to enhance awareness of the diversity of these reactions.