What is Hypersensitivity Syndrome?

Hypersensitivity Syndrome is your body’s reactions to medications that result from an enhanced immunologic or inflammatory response. Infection-fighting T-cells in your immune system are unleashed in response to the medication which causes eruptions on your skin and damage to your internal organs.

Several factors make Hypersensitivity Syndrome different from an ordinary drug reaction. These include when it:

• Symptoms appear to go into remission, but relapses can occur later
• Causes autoimmune disorders to develop down the line
• Re-activates common herpes viruses that may be dormant in your body
• Involves more than one organ in your body

What Are The Symptoms Of Hypersensitivity Syndrome?

While several drug allergies cause an instant reaction, the symptoms of Hypersensitivity Syndrome generally appear 3 weeks to 3 months after the medication was started. Symptoms can come and go for months or even years.

Common symptoms may include:

• Scaly, flaky skin
• Fever
• Facial swelling
• A pink or red rash with or without pus-filled bumps or blisters
• Swollen or tender lymph nodes
• Swollen saliva glands
• Difficulty moving normally
• Headache
• Dry mouth
• Abnormalities in your white blood cell counts
• Seizures
• Coma

Who’s At Risk for Hypersensitivity Syndrome?

Scientists have discovered that genes play an essential role in whether you’re likely to have a severe drug reaction. However, genetics is not the only factor. Studies show you may be more likely to experience Hypersensitivity Syndrome if:

• You’re over 20 years old
• You’ve had a rheumatic or collagen rheumatic disease before
• You’ve had a viral infection in the past few weeks
• You have a condition that requires you to take antibiotics often

Possible Causes of Hypersensitivity Syndrome

Scientists are still learning about these interactions, but what they have discovered so far shows that certain drugs are more likely to be involved in these reactions:

• Medications used to treat tuberculosis include Ethambutol, Rifampin, Isoniazid, Pyrazinamide, and Streptomycin
• Seizure medications including Mexiletine, Phenytoin, Phenobarbital, Carbamazepine, Lamotrigine, Valproic Acid, and Zonisamide
• Antibiotics such as Ampicillin, Azithromycin, Dapsone, Amoxicillin, Levofloxacin, Piperacillin/Tazobactam, Clindamycin, Minocycline, and Vancomycin
• Antiretrovirals such as Nevirapine and Efavirenz
• Anti-inflammatory medications, including ibuprofen, celecoxib, and diclofenac
• Cancer therapies including Sorafenib, Vismodegib, Imatinib, and Vemurafenib
• Drugs used to treat hepatitis C, including Boceprevir and Telaprevir
• Allopurinol and Febuxostat, lower uric acid in people with gout, kidney stones, and cancer
• Rivaroxaban, a blood thinner
• Acetaminophen, an over-the-counter pain reliever
• Omeprazole, an over-the-counter heartburn medication  
• Sulfasalazine, an arthritis medication

How Is Hypersensitivity Syndrome Treated?

The first step in treating Hypersensitivity Syndrome is to stop the medication that’s causing the reaction. You must be prepared for your symptoms to get worse right after you stop taking the medication. 

It’s also important to understand that your symptoms may come and go for some time after you’re treated. That pattern is also common with this condition. After stopping the medication, your doctor may treat you with corticosteroids to control some of your symptoms. If you’ve developed a secondary infection as a result of the reaction, you may also need a course of antibiotics.