Serum sickness is a delayed immune response to a certain kind of antiserum (i.e. given after a person is exposed to a bite from a poisonous snake or a rabid dog) or medication.
This condition is very similar to an allergic response, in which, the immune system of the body mistakes the protein from the medication or antiserum as a harmful foreign body and triggers an immune response.
The condition is referred to as serum sickness, due to the primary involvement of the serum (i.e. the liquid part of the blood), which contains the antibodies.
What Causes Serum Sickness?
The blood comprises of plasma and blood cells (both red and white). Plasma is the fluid component of the blood which contains several proteins which includes antibodies, which are a part of the body’s immune system and provide protection against infections.
Anti-serum is prepared from the plasma of animal or other healthy humans to provide temporary protection to a person exposed to a poisons or infections, till the body of the person naturally develops immunity against the toxin. Medications also provide similar protection from infection and allow time to the body to develop its own immune response against the germ.
However, in serum sickness, the body’s immune system, misidentifies the injected medication or anti-serum (which is actually meant to provide temporary protection) as a toxin and triggers an allergic reaction. There are certain medications that have been found to be associated with serum sickness which include,
- Commonly used antibiotics like Penicillin and Cephalosporin.
- Barbiturates and Fluoxetine used for depression.
- Thiazides, used as diuretics
- Aspirin or products containing aspirin.
- Snake venom anti-serum
In certain cases, wasp bites or bee stings can also trigger serum sickness, though it is relatively rare.
Signs And Symptoms Of Serum Sickness
The signs and symptoms of serum sickness are very similar to those of an allergic reaction, but relatively more severe in nature. The common symptoms include,
- Fever with general feeling of ill health.
- Itching and formation of hives on the skin. In some cases the condition may be associated with development of rash and red discoloration.
- Joint pain
- Swelling of the lymph nodes is another common symptom.
- Gastro-intestinal symptoms like diarrhea, nausea and vomiting may develop.
- Respiratory symptoms include wheezing and breathlessness.
Unlike allergic reaction that usually develops within a few hours of receiving the medication, the symptoms of serum sickness develop over one to three weeks from the time of exposure. Some of the possible complications associated with the condition include,
- Anaphylactic shock which may result in sudden drop in blood pressure and can be a life threatening situation. This condition requires immediate hospitalization.
- Inflammation of arteries and veins is another complication associated with this condition.
- In some cases, the condition may be associated with swelling of legs, arms and face with reddish discoloration, which is referred to as angioedema.
How Long Does Serum Sickness Last?
Generally serum sickness develops between 7 to 21 days post the exposure to the medication, however it may develop as soon as 1 to 3 days post exposure in individuals who have already been exposed to the substance in the past.
If treated promptly the symptoms of serum sickness usually disappear within a few days, however if the condition is associated with complications, recovery may be delayed.
Maintaining a health record to avoid the use of the same drug/antiserum in future is essential to avoid a repeat reaction.