Serum Sickness

Serum sickness results from a reaction to an antigen, a protein that the body recognizes as foreign. The classic example of a cause of serum sickness is an antiserum administered following a snakebite to counter the poisonous venom. Today, the most common cause of serum sickness is the antibiotic penicillin. Serum sickness will usually develop within 7 to 10 days after initial exposure to the antigen; at times, however, the reaction does not develop until as long as three weeks later. With subsequent exposures, serum sickness tends to develop more rapidly (within one to four days) and only a very small amount of the substance may cause an intense response.

Signs and Symptoms

The first signs of serum sickness are redness and itching at the injection site. Other signs and symptoms include:

What Causes It?

Antigens, the proteins described earlier, stimulate the body to produce antibodies. These antibodies form complexes with the antigens and, in the case of serum sickness, become trapped on endothelial surfaces—layers of cells that line the heart, blood vessels, lymph vessels, and other body cavities. This leads to a series of immune-system reactions that cause the symptoms of serum sickness.

Penicillins are the most common cause of serum sickness. Other causes include:

Who's Most At Risk?

You are more likely to suffer from serum sickness if

What to Expect at Your Provider's Office

A healthcare provider will look for typical signs and symptoms and ask about recent exposure to any antiserum. Blood and urine tests and tests of skin with lesions may aid the diagnosis.

Treatment Options


Drug Therapies

Doctors will typically prescribe antihistamines or analgesics for serum sickness. If symptoms don't respond to this treatment, they may prescribe corticosteroids, such as prednisone. Normally, there is no need for hospitalization. In severe cases providers may resort to plasmapheresis—a procedure for removing blood, separating plasma from the blood, then replacing the blood along with plasma substitutes.

Complementary and Alternative Therapies

Serum sickness requires immediate conventional medical attention. Scientific studies have not yet evaluated the effectiveness of CAM therapies in treating serum sickness. However, nutritional and herbal treatments may support conventional treatment by helping to reduce inflammation and stabilize the immune system. Although certain CAM measures may help relieve symptoms of serum sickness, others may worsen serum sickness by increasing the number of circulating immune complexes (see section entitled What Causes It? for description of immune complexes).

Certain nutrients used in clinical practice can stabilize immune function and may lessen reactions such as serum sickness. These include: The use of these substances for serum sickness is theoretical and has not been tested scientifically.

Omega-3 fatty acids, found in fish oil, are generally used to reduce inflammation; however, these substances along with eicosapentanoic acid (EPA), should be avoided in the case of serum sickness because of a recent animal study showing increased levels of antigen-antibody immune complexes following ingestion of fish oil. Increased circulation of immune complexes may worsen serum sickness.

Anti-inflammatory herbs may, theoretically, lessen some of the symptoms of serum sickness: Toki-shakuyaku-san (TSS), a Japanese (Kampo) formula that contains six herbs, was found to decrease circulating immune complexes in animals. The main active ingredient to help clear the complexes was thought to be: Herbs that may cause allergic hypersensitivity reactions, such as cayenne pepper (Capsicum spp., used to treat forms of arthritis), should be avoided in the case of serum sickness.

To date, no scientific studies have investigated the value of homeopathic remedies in treating serum sickness. However, homeopaths commonly use the following for hives and other symptoms related to serum sickness: An experienced homeopath considers each individual case and may recommend treatments to address both the underlying condition and any current symptoms.

Massage should not be used in cases of serum sickness as it may promote inflammation as well as lower blood pressure.

Prognosis/Possible Complications

Serum sickness usually resolves in 7 to 10 days, with full recovery in 2 to 3 weeks. However, it may lead to nervous system disorders as well as a life-threatening allergic reaction called anaphylaxis.

Following Up

Healthcare providers should monitor acutely ill persons for rare instances of myocarditis (inflammation of the heart muscle) and peripheral neuritis (nerve inflammation).


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