REACTIVE IATROGENIC DERMATITIS: MORE THAN JUST SIDE EFFECTS

Reactive Iatrogenic Dermatitis (RID), in med-speak that means the body’s response to a medical treatment that results in skin inflammation. It’s a name that describes what are commonly called injection site reactions (ISRs) in terms that recognize the reality and severity of a condition that affects millions of patients worldwide. The term RID also conveys the fact that the pain, redness, swelling and even scarring that can occur after injection of a medicine into the skin result from a treatable inflammatory reaction.

RID can occur after subcutaneous (under the skin) injection of many prescription medications, including those that are important for lifelong treatment of debilitating diseases such as Multiple Sclerosis and Rheumatoid Arthritis. At least 60 marketed drugs, including many of the most prescribed biologic drugs, report an RID rate of greater than 25%.Symptoms range from a painful red spot that lasts for a few hours or several days all the way up to an open wound that persists for weeks and causes severe scarring at the injection site. Repeated bouts of even mild RID at the injection site can lead to erosion of the underlying fat (lipodystrophy) or formation of scar tissue (fibrosis) over time.

While the direct effect on the therapeutic outcomes of medical treatments that cause RID is unknown, the indirect effects are well-documented. These indirect effects include patients frequently skipping doses of their medicine or quitting treatment altogether even when the consequence is as severe as confinement to a wheelchair and permanent loss of limb function, such as in Multiple Sclerosis or Rheumatoid Arthritis.

Patient forums and support groups have emerged to help patients learn about ways other sufferers are coping with RID. Many pharmaceutical companies sponsor online and telephone support for patients using their drugs. Other support groups have formed spontaneously through online social networks, such as Facebook. Frequently recommended treatments include ice before and/or after injection, heat after injection and over-the-counter topical anti-inflammatory balms, but these do not effectively address the problem. There is a clear need for improved therapies that reduce or eliminate RID.

In order to understand the underlying cause of RID, Celtaxsys has conducted skin tests in patients taking several important drugs. The tests implicate the cells of innate immunity in the induction of RID. Because RID also occurs in veterinary medicine, we have been able to identify a model system that replicates the human condition and allows us to study ways of modulating the local innate immune response to reduce RID. Our goal is create improved medicines for treatment of debilitating diseases by significantly reducing or eliminating RID.

 

 

Figure Caption: RID at Injection Site in Human Skin

Human skin biopsy section showing injection site (circled) shortly after administration of an MS medication. The red channel at the top is the needle puncture site, and the blue dots below it are mostly immune cells.