Allergic purpura is a type of inflammation in the small blood vessels causing bleeding in the skin, joints, intestines and kidneys. Although this type of allergic reaction can affect anyone, it is most common in children and young adults. This condition is also called anaphylactoid purpura, Henoch-Schonlein Purpura or HSP. According to the National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC), recurrences happen in one out of every three people and more frequently in the first few months after the initial episode.
Causes
According to the NKUDIC, the cause is not fully understood. Theoretically it occurs when the immune system responds to an infection but continues to attack the cells in the body after the infection has cleared. This theory is supported by the fact that allergic purpura can recur or worsen during an upper respiratory infection. According to the Mayo Clinic, triggers can also include specific antibiotics or antihistamine medications, vaccinations for measles, typhoid, yellow fever or cholera, cold weather or chemical exposure.
Symptoms
Symptoms of allergic purpura are all related to the leaking blood vessels at the capillary level. According to the U.S. National Library of Medicine, symptoms include joint pain, gastrointestinal problems, glomerulonephritis, abdominal pain, bloody stools, hives, nausea, diarrhea, painful menstruation, vomiting and purple spots on the skin commonly over the buttocks, lower legs and elbows.
Blood and Urine Testing
A thorough medical history and physical examination is an integral part of determining the appropriate testing to confirm a diagnosis. According to the Mayo Clinic, there is no one single laboratory test that can confirm the problem of allergic purpura. However, there are specific tests that can help rule out other diseases to help your physician confirm a diagnosis. An elevated IgA may be suggestive of the diagnosis of allergic purpura but it is not conclusive. Another blood test that may be elevated is the erythrocyte sedimentation rate that indicates the level of inflammation in the body. A platelet count may also be added to the testing to look at the number of cells that help blood to clot. Urine testing will evaluate the function of your kidneys but will not diagnose allergic purpura.
Biopsy and Imaging
According to the NKUDIC, if other testing is inconclusive then a small skin sample may be taken for examination under a microscope. The skin biopsy may have large numbers of white cells and deposits of IgA, a protein made by the immune system to fight infection. These results may point to allergic purpura. A kidney biopsy may be done to help your doctor determine the correct medication needed to help treat kidney disease that can result from allergic purpura. Kidney testing is not a common test for people with allergic purpura.
Treatment
According to the Mayo Clinic, allergic purpura will usually improve on its own within four to six weeks without any lasting effects. Treatment will be focused on alleviating the discomfort and preventing complications. In some circumstances children may require hospitalization if they have trouble staying hydrated, severe stomach pain, significant joint problems or serious kidney complications. More frequently you will be prescribed bed rest for a short period of time, fluids and anti-inflammatory medications to relieve the pain and discomfort.
