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 NICE CKS Cereser et al. 2017.
• Infections caused by opportunistic or unusual pathogens, or infections that are unusually severe or prolonged NICE CKS 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 NICE CKS Grenier et al. 2024.
• Non-infectious manifestations such as autoimmune disorders, lymphoproliferation, or granulomatous disease, which can accompany certain PIDs NICE CKS Jamee et al. 2020.
• Family history of immunodeficiency or early deaths from infections may also raise suspicion NICE CKS.
• Failure to respond adequately to standard antimicrobial therapy or frequent need for intravenous antibiotics or hospital admissions for infections NICE CKS 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 NICE CKS.