What is anaphylactoid purpura?
Anaphylactoid purpura is more commonly called Henoch-Schoenlein
purpura or HSP. It is an illness in which small blood vessels get
inflamed. It can involve many different organs in the body. The
inflamed blood vessels may bleed into the skin and cause a red or
purple rash called purpura.
What is the cause?
The cause of this illness is not completely understood.
Researchers believe that there is some inflammation (swelling) in
the blood vessels, which causes symptoms. The illness is often
seen in children who have had a viral upper respiratory infection
(a cold) a few weeks earlier. The antibodies produced by the
child's body to fight the cold may contribute to development of
the illness.
HSP was thought to be an allergic reaction to medicines, insect
bites, cold, chemicals, or certain foods. HSP is not an inherited
disease. It is not contagious and cannot be prevented.
What are the symptoms?
HSP can occur with some or all of the following symptoms:
- Rash: The rash is often located on the buttocks and legs. The
rash may first look like hives, but usually it changes to
purplish or brownish bruises within 1 to 2 days. There is
almost always some rash on the ankles.
- Painful swelling of the joints: The joints most often affected
by pain are the knees and ankles. The joint pain may be severe
enough to make your child unable or unwilling to walk.
- Abdominal pain: If your child has severe abdominal pain or
blood in his or her stools, the healthcare provider may need
to do tests to rule out other, more serious causes of these
symptoms.
- Fever
- Blood in the urine.
How is it diagnosed?
HSP is diagnosed with a physical exam. Blood tests may be done to
check how well your child's kidneys are working and to check your
child' blood count. Your healthcare provider may also check your
child's urine for blood or protein, and your child's stool for
blood.
What is the treatment?
There is no medicine that can cure this illness. There is also no
way known to predict who will get HSP and there is no way to
prevent it. The illness may last for several months and the
symptoms may come and go during this time. The older your child
is, the more likely it is that he or she will experience the
symptoms again. Your child will eventually get better on his or
her own. Until then, you can treat your child's symptoms.
- Anti-inflammatory medicines
The best and safest medicine to give to help with the pain and
inflammation of swollen joints is ibuprofen (for example,
Advil or Motrin). Use the same dose you use to treat your
child's fever. Do not use aspirin. Acetaminophen (for
example, Tylenol) may help with the pain, but it will not
relieve swelling and inflammation. Your child's dose of
ibuprofen is ____ mg every 6 to 8 hours as needed for pain.
- Steroid medicines
Your child's healthcare provider may prescribe a steroid
medicine, such as prednisone, to reduce inflammation in the
intestine. The steroid may help control pain and intestinal
bleeding.
- Fluids
Encourage your child to drink plenty of fluids and to eat a
normal diet as much as is possible.
How long will it last?
Most children recover from anaphylactoid purpura completely and
have no further problems. Rarely, however, the kidneys can be
affected. It is important for your child to see a healthcare
provider for blood pressure checks and urine tests every 1 to 2
months over the next 2 years.
When should I call my child's healthcare provider?
Call IMMEDIATELY if:
- Your child develops a fever and the purplish rash.
- Your child starts vomiting.
- Your child's abdominal pain is getting more severe, or there
is more blood in your child's bowel movements.
- Your child has not urinated in over 12 hours.
- Your child begins to look puffy, especially around the face or
eyes.
- Your child's urine has blood in it.
- Your child is acting very sick.
Call during office hours if:
- You have other questions or concerns.
Written by the Section of Pediatric Emergency Medicine, The Children's Hospital, Denver.
This content is reviewed periodically and is subject to
change as new health information becomes available. The
information is intended to inform and educate and is not a
replacement for medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
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