Tuberculosis is a serious and potentially deadly bacterial infection that causes weight loss, cough and fever, among other symptoms. During the 1600s and 1700s, the disease was prevalent in Europe and was responsible for approximately 25 percent of all deaths. This disease is still a serious health problem in third world countries, according to the eMedicine Health website. A skin test is used to test individuals who have been exposed to the bacterium.
The Mantoux test is designed to identify the M. tuberculosis bacterium that causes tuberculosis. A health care provider injects a small amount of PPD, or purified protein derivative, under the skin. PPD is made up of inactive tuberculosis bacterium. The injection site will initially have a small, raised, fluid-filled lump that quickly dissolves into the body. The health care worker will examine the injection site between 48 and 72 hours later to check for a positive reaction.
Symptoms of Hypersensitivity
The Health & Human Services Department of Clallam County, Washington warns that patients may develop some redness or bruising after a TB test. In addition, there may be some itching or irritation. None of these symptoms is cause for alarm. The primary symptom of a positive reaction is a swollen, hard lump at the injection site with clearly outlined and raised edges. The size of the circle is used to determine whether or not the person has been infected with tuberculosis. Medicinenet.com notes that there is a low risk of a person developing a severe allergic reaction to the TB test. The arm can become swollen and red in individuals who have had tuberculosis in the past. In addition, a vaccine called BCG (bacille Calmette-Guerin) can cause an allergic reaction or create a false positive result. This vaccine is sometimes given to people who live or work outside of the United States, according to the Centers for Disease Control and Prevention.
Active and Latent Tuberculosis
Just because a person does not have any symptoms, such as coughing or weight loss, does not mean that he does not have tuberculosis. Many people carry a latent form of the TB infection. Their bodies may control growth of the tuberculosis bacterium, but they still have the infection. Latent tuberculosis can become active in people who have weak immune systems. Tuberculosis is highly contagious and can be transmitted from one person to another through droplets that are passed by breathing, sneezing or coughing on others.