Last reviewed: August 2019
Last updated: March  2018



History and exam

Key diagnostic factors

  • presence of risk factors
  • recurrent infection
  • infection with Streptococcus pneumoniae or Haemophilus species
  • infection with atypical pathogens
  • repeated antibiotic use
  • respiratory crackles, high-pitched inspiratory squeaks, rhonchi

Other diagnostic factors

  • absence from school/work
  • failure to thrive
  • diarrhoea
  • sinusitis
  • pallor
  • tympanic membrane perforation
  • illness after live vaccines
  • weight loss, night sweats, fevers
  • oedema
  • alopecia, goitre, vitiligo
  • eczema
  • small/absent tonsils
  • lymphadenopathy and hepatosplenomegaly
  • hx of coeliac disease or transfusion reactions
  • muscle fatigability, ptosis, diplopia (if thymoma present)
  • dysmorphic features
  • neurological involvement

Risk factors

  • young children and early adulthood (primary disease)
  • old age (secondary disease)
  • male gender
  • positive FHx of primary immunodeficiency
  • severe protein-losing state
  • haematological malignancy
  • anticonvulsant and immunosuppressive drugs

Diagnostic investigations

1st investigations to order

  • FBC
  • serum IgG
  • serum IgA
  • serum IgM
  • serum and urine electrophoresis
  • urine dipstick
  • serum creatinine
  • serum albumin
  • liver function tests (LFTs)
  • sputum culture
  • stool culture
  • chest x-ray
Full details

Investigations to consider

  • flow cytometry: lymphocyte subsets
  • specific antimicrobial antibodies
  • test immunisation response
  • IgG subclasses
  • flow cytometry: protein expression
  • genetic testing
  • enzyme assays
  • abdominal ultrasound
  • CT chest/sinuses
  • CT abdomen
  • PFTs
  • lymph node biopsy
  • small- and large-bowel biopsy
  • PCR for viral infection
  • hepatitis B surface antigen (HBsAg), hepatitis B and C PCR
Full details

Treatment algorithm


Authors VIEW ALL

Consultant Immunologist

Frimley Park & St Thomas' Hospital





MYK serves on the advisory board for Allergy Therapeutics, which manufactures allergy immunotherapy products and allergy skin testing products.

Dr Mohammed Yousuf Karim would like to gratefully acknowledge Dr Patrick Yong and Dr Zoe Adhya, previous contributors to this monograph. PY and ZA declare that they have no competing interests.

Peer reviewers VIEW ALL

Associate Professor of Pediatrics

University of New South Wales

Department of Immunology and Infectious Diseases

Sydney Children's Hospital





JBZ declares that he has no competing interests.

Professor of Medicine and Pediatrics

Immunology Institute

Mount Sinai School of Medicine

New York



CCR is an author of several references cited in the monograph.

Honorary Clinical Scientist

UCL Centre for Primary Immunodeficiency

University College London Medical School

Department of Immunology

Royal Free Hospital




DW declares that he has no competing interests.

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