Secondary immunodeficiencies occur when the immune system is weakened due to external factors rather than genetic issues. These factors can include infections, such as HIV, certain medications like corticosteroids, or chronic diseases such as diabetes and cancer. As a result, the body becomes more susceptible to infections and illnesses. Unlike primary immunodeficiencies, which are present at birth, secondary immunodeficiencies can develop at any age. Treatment often focuses on managing the underlying cause, such as improving nutrition or adjusting medications. In some cases, therapies like immunoglobulin replacement may be used to help boost the immune response.