Diagnostic Test Needed to Identify Drugs Causing Stevens-Johnson Syndrome: Study

A new study highlights serious flaws with current testing methods used to identify drugs that trigger Stevens-Johnson Syndrome (SJS), a painful and debilitating skin reaction that can result as an allergic side effects from various medications.

Doctors treating patients for Stevens-Johnson syndrome often rely on biased information, and incorrectly label the condition as allergic to certain drugs, researchers warn in the new study. They also may fail to identify the correct drugs actually triggering the condition. However, researchers indicate that both scenarios could be avoided with standardized systems and a diagnostic test for SJS, according to findings of research published June 21 in JAMA Dermatology.

Stevens-Johnson syndrome (SJS) typically results in a severe rash and blistering in the mouth, eyes, ears nose or genital area, essentially causing the skin to burn from the inside out. In severe cases, the condition can progress to toxic epidermal necrolysis (TEN), which often results in the need for treatment in a hospital burn unit or ICU, and may cause blindness or death.

Doctors Often Incorrectly Label Stevens-Johnson Drugs

Prior studies have suggested several types of anticonvulsants, antibiotics and non-steroidal anti-inflammatory drugs (NSAIDS) may cause Stevens-Johnson syndrome risks. Specific antibiotics, like penicillin and sulfa drugs, are also linked to a high risk for Stevens-Johnson syndrome. However, the condition can also result from a wide variety of other medications, including some that may not current contain label warnings about the risk.

In this new study, doctors from Brigham and Women’s Hospitals in Boston analyzed 48 patients with clinically confirmed SJS/TEN cases from January 2000 to July 2018. The researchers found that the average patient was taking 6.5  different drugs at the onset of SJS/TEN. Seventeen patients were labeled as allergic to a single culprit drug. However, across all patients, 104 drugs were linked to SJS/TEN reactions and were added to allergy lists.

The Algorithm for Drug Causality for Epidermal Necrolysis, a computerized scoring system that identifies SJS/TEN triggering drugs, found 28 cases which were inconsistent with doctors’ own conclusions. Specifically, they confirmed an additional nine drugs labeled as SJS/TEN triggers that physicians missed. The computer scoring system also cleared 43 drugs that physicians labeled as allergens.

Additionally, researchers found doctors failed to consider factors other than drug allergies as SJS/TEN triggers. Prior research suggests infections like pneumonia and hepatitis can also cause the condition.

Researchers blamed these discrepancies on flaws in how doctors identify drugs linked to SJS/TEN using just their medical knowledge. Doctors employing this method rely on generalized information about drugs linked to the condition, and patient drug exposure timing. However, researchers say this approach is known to produce skewed, inaccurate results.

Diagnostic Biopsy Tests Needed

The researchers determined that current SJS/TEN drug identification methods are prone to bias, potentially leading to overlabeling patients allergic to nonculprit drugs, and failure to identify actual drugs causing the condition. Doctors should utilize a diagnostic biopsy test for the most accurate SJS/TEN culprit drug identification, they recommended.

If a diagnostic biopsy test is not immediately available, physicians should use a systematized unbiased approach, such as a vetted drug risk database combined with a computerized scoring algorithm, the researchers indicated.

“It is important to identify a culprit drug in SJS/TEN as accurately as possible. In the absence of a criterion standard laboratory test, the onus is on clinicians to make that determination,” the researchers wrote. “This study’s data suggest that culprit drug identification is commonly very challenging.”