What are the key clinical features that suggest a primary immunodeficiency disorder in adults?

Key clinical features suggesting a primary immunodeficiency disorder (PID) in adults include:

• Recurrent, severe, or unusual infections, particularly of the respiratory tract such as pneumonia, sinusitis, and bronchitis, which may be persistent or difficult to treat ¹ (Cereser et al., 2017).
• Infections caused by opportunistic or unusual pathogens, or infections that are unusually severe or prolonged ¹ (Jamee et al., 2020).
• Chronic pulmonary complications including bronchiectasis and interstitial lung disease, often visible on imaging such as high-resolution computed tomography (HRCT) scans, which may indicate underlying humoral immunodeficiency ¹ (Grenier et al., 2024).
• Non-infectious manifestations such as autoimmune disorders, lymphoproliferation, or granulomatous disease, which can accompany certain PIDs ¹ (Jamee et al., 2020).
• Family history of immunodeficiency or early deaths from infections may also raise suspicion ¹.
• Failure to respond adequately to standard antimicrobial therapy or frequent need for intravenous antibiotics or hospital admissions for infections ¹ (Cereser et al., 2017).

These features should prompt consideration of PID and referral for immunological assessment, including immunoglobulin levels and lymphocyte subset analysis, to confirm diagnosis and guide management ¹.