Hypersensitivity Vasculitis (HV) is a form of the disease – small vessel vasculitis. In most cases, there are no apparent causes of this disease. But when diagnosed, they can occur in the form of skin diseases involving other organs like the joints and kidneys. In cases, where the cause is not known are known as idiopathic.
For the remaining 50% cases the causes can be attributed to drugs, infections, food, other diseases, allergic reactions, infections, blood cell cancers, immune system diseases, genetic inheritance and presence of certain chemicals in the environment. Some of the most common causes are discussed below.
Important Causes Of Hypersensitivity Vasculitis
Although this pointer accounts for only about 1% of the reasons that cause hypersensitivity vasculitis, still it is considered as one of the major causes of Hypersensitivity Vasculitis. Lymphoproliferative diseases like hairy cell leukemia or any type of tumors can be attributed to the reason of this disease. Some patients recover well with tumor therapy. Blood cell cancers affecting the blood cells like lymphoma are also said to be the causes of hypersensitivity vasculitis.
The most common cause found to be triggering hypersensitivity vasculitis is drugs. Though, this disease can be caused by any drug, more often than not, antibiotics, especially beta-lactams like penicillin, amoxicillin and cephalosporins are said to be the triggers. NSAIDs or nonsteroidal anti-inflammatory drugs and diuretics can also cause hypersensitivity vasculitis.
Among other drugs, the one worthy of mentioning is the sulphonamide – which belongs to a class of antibiotics, certain blood pressure medications and phenytoin – which are anti-seizure medications. Some kind of allergic reactions to these medications are the causes.
Reduced Blood Flow
Another cause of hypersensitivity vasculitis is reduced blood flow. Blood flow itself can be reduced because of several reasons like slowing blood flow in the lower legs or stasis, high fat content reducing flow of blood to the thighs and buttocks compared to the leaner areas.
Certain medications that restrict the flow of blood in the blood vessels, cold weather and varicose veins etc. are all thought to trigger reduced blood flow. Antibodies and complements that circulate in the blood can cause hypersensitivity vasculitis when the flow of blood is reduced due to the above mentioned reasons.
An immune disorder that affects the tendons, connective tissues and bones also known as collagen vascular diseases are said to be responsible for 10-15% of the cases of hypersensitivity vasculitis.
Diseases like rheumatoid arthritis or an autoimmune disease that attacks the tears and saliva producing glands called Sjogren’s syndrome or lupus erethematosus, which is another auto-immune disease that causes lesions on the skin have all been held responsible for hypersensitivity vasculitis. Other diseases like inflammatory bowel disease, polyarteritis nodosa are examples too that can act as the major causes of hypersensitivity vasculitis.
In cases of upper respiratory tract infections or beta-hemolytic streptococcal infection, the antibiotics used can trigger this disease. As symptoms are not known till after the disease is diagnosed, it is almost impossible to ascertain whether the infection is the cause or the drug. Most cases concerning cryoglobulinemia are the outcomes of hepatitis C virus infection and the cases of hepatitis B virus infection causing Polyarteritis Nodosa. Severe bacterial infection like bacterial endocarditis cannot be ruled out too.
There are other nominal causes like food and food additives which can also in some rare cases cause this disease. If the correct cause can be identified, the treatment becomes simple and in most cases it can be arrested.