Serum Sickness: Care Instructions

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Your Care Instructions

Serum sickness is an unexpected reaction to some medicines. Medicines that can cause it include antibiotics like penicillin. Some vaccines, insect stings, or spider bites might also cause it.

Symptoms may start 7 to 10 days after you take the medicine. (They may start sooner if you have had the medicine before.) You might have a rash, hives, or joint pain. You may also have a fever, a headache, or swollen glands. Sometimes you just feel sick. Your symptoms will probably go away on their own, but they may last up to several weeks.

Your doctor might give you medicine to help your fever, pain, or skin problems. The doctor may also prescribe a steroid medicine. It can help calm down the body's response.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

How can you care for yourself at home?

  • Stop taking medicine that caused the sickness if your doctor tells you to. Don't take that kind of medicine again. Taking it even many years later can make you sick again. Your doctor may recommend a different medicine.
  • If you have a fever or joint pain, ask your doctor if you can take an over-the-counter pain medicine, such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve). Be safe with medicines. Read and follow all instructions on the label.
  • If you have a rash or hives, take a nondrowsy antihistamine, such as loratadine (Claritin). Be safe with medicines. Read and follow all instructions on the label.

When should you call for help?

Call 911 anytime you think you may need emergency care. For example, call if:

  • You have severe trouble breathing.

Call your doctor now or seek immediate medical care if:

  • You have a rash in your mouth or on your genital area.
  • You have blisters on your body.
  • You have new symptoms, such as a cough or belly pain.
  • Your joint pain gets worse.
  • You have new or worse trouble breathing.

Watch closely for changes in your health, and be sure to contact your doctor if:

  • You have a new or higher fever.
  • You do not get better as expected.

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.