Risk factors for hypersensitivity skin reactions

Mohannad Abu-Hilal, MD, is an associate professor of Medicine and head and of the Dermatology Division at McMaster University.

What are the risk factors for severe hypersensitivity skin reactions?

The most well studied is actually the Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) reaction. And for this group of reactions, underlying malignancy, underlying cancer—especially brain tumors, having immune deficiency, having some other autoimmune diseases like lupus, they are all increased risk of having a severe drug reaction.

One important thing is genetic predisposition. Some individuals have genetic alleles called human leukocyte antigen (HLA) alleles, and those may predispose you to have a severe reaction to certain medications.