Secondary immunodeficiency occurs when the immune system is weakened due to external factors, rather than being inherited. This condition can result from various causes, including infections like HIV, certain medications such as chemotherapy, or chronic diseases like diabetes. These factors can impair the body's ability to fight off infections and diseases. Unlike primary immunodeficiency, which is genetic, secondary immunodeficiency can develop at any age. Individuals with this condition may experience frequent infections, delayed recovery, and increased susceptibility to illnesses. Proper management and treatment of the underlying cause are essential for improving immune function and overall health.