Primary Immunodeficiency Diseases (PIDD) comprise a group of more than 100 diseases which are due to defects in the body's defenses (immune system). These diseases affect thousands of infants, children, and adults in the United States.

In most cases, PIDD are associated with acute or recurrent infections depending on the portion of the immune system affected. Most PIDD are inherited in our genes, so they are present at birth, but they often do not become apparent or diagnosed until late in childhood, or even in adult life. It often takes time for a pattern of recurrent infections or other symptoms to develop before a PIDD is suspected. There are more than 100 different genetic causes of PIDD.

Signs that you or your child might have a PIDD include:

• Recurrent, unusual, or difficult to treat infections
• Poor growth or loss of weight
• Recurrent pneumonia, ear infections or sinusitis
• Multiple courses of antibiotics or IV antibiotics necessary to clear infections
• Recurrent deep abscesses of the organs or skin
• A family history of PIDD
• Swollen lymph glands or an enlarged spleen
• Autoimmune disease

If you think you have a PIDD, talk to an allergist/immunologist, a pediatrician or internist with two to three years additional training to manage allergies, asthma and immunodeficiencies. Some PIDD can mimic other conditions including allergy, asthma, or eczema and vice versa, so evaluation by an allergist/immunologist is extremely helpful for reaching a diagnosis and developing an effective treatment plan.