The goal is to identify whether the infections are due to a local problem, an underlying systemic disease, or an immune system disorder.

 

 

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1. Detailed Clinical History

• Type of infections: Skin, respiratory, urinary, gastrointestinal, etc.

• Frequency and duration: How often and how long they last.

• Severity: Mild or requiring hospitalization/IV antibiotics.

• Location: Same site or multiple different sites.

• Response to treatment: Partial, complete, or resistant to antibiotics.

• Family history: Immune deficiencies or autoimmune diseases.

• Environmental exposure: Travel, pets, work, daycare, etc.

• Medications: Immunosuppressants, steroids, chemotherapy.

• Vaccination history: Especially pneumococcus, influenza, etc.

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2. Physical Examination

• Look for signs of chronic illness, lymphadenopathy, organomegaly.

• Examine affected areas (e.g., sinuses, lungs, skin, urinary tract).

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3. Laboratory Tests

• Complete blood count (CBC) with differential: Look for leukopenia or neutropenia.

• Immunoglobulin levels (IgG, IgA, IgM, sometimes IgE).

• Lymphocyte subsets (T cells, B cells, NK cells).

• Complement levels (CH50, C3, C4).

• Neutrophil function tests (e.g., nitroblue tetrazolium test or oxidative burst).

• HIV testing (if risk factors or unexplained immunosuppression).

• Diabetes screen: Elevated glucose can predispose to infections.

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4. Microbiological Workup

• Cultures of infected sites (blood, urine, sputum, wound, etc.).

• Identify organisms: Recurrent infections with the same organism vs. different ones.

• Look for antibiotic resistance patterns.

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5. Imaging Studies

• CT or MRI: Evaluate for chronic infection or anatomical defects (e.g., sinus CT, chest CT, abdominal imaging).

• Ultrasound: For abscesses, urinary tract abnormalities.

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6. Special Tests (If Indicated)

• Sweat chloride test or genetic testing for cystic fibrosis.

• Bronchoscopy: For recurrent pneumonia or unexplained cough.

• Urinary tract imaging: For recurrent UTIs.

• Bone marrow biopsy: If hematologic malignancy is suspected.

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7. Referral to Specialist

• Immunologist: For suspected primary or secondary immunodeficiencies.

• Infectious disease specialist: For difficult-to-diagnose or manage infections.

• Endocrinologist: For metabolic disorders like diabetes.

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Common Categories of Causes

• Anatomic defects (e.g., sinus blockage, vesicoureteral reflux)

• Immunodeficiencies:

  • Primary (genetic, e.g., CVID, X-linked agammaglobulinemia)

  • Secondary (HIV, chemotherapy, immunosuppressants, diabetes)

• Chronic diseases (e.g., diabetes, malignancy)

• Environmental/behavioral factors (e.g., poor hygiene, overcrowding)

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If you’d like, you can tell me more about the type of infections or symptoms you’re referring to, and I can help outline a more tailored diagnostic approach.