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PubMed This is a summary of 20 peer-reviewed journal articles Updated
Pulmonology

Causes of DAH: Immune vs. Non-Immune

At a Glance

Diffuse Alveolar Hemorrhage (DAH) is a sign of bleeding in the lung's air sacs. It is caused by either immune-mediated conditions, where the body attacks its own blood vessels, or non-immune factors like medications, toxins, or structural heart issues.

Finding the cause of Diffuse Alveolar Hemorrhage (DAH) is like solving a puzzle. DAH is not a single disease, but a signal that something is damaging the delicate blood vessels in your lungs. Doctors generally divide these causes into two categories: immune-mediated (where the immune system attacks the body) and non-immune (where external factors or physical pressure cause the damage) [1][2].

Immune-Mediated Causes: The Body Attacking Itself

In immune-mediated DAH, your immune system mistakenly identifies the tiny blood vessels (capillaries) in your lungs as “foreign” and attacks them [1]. This leads to capillaritis, an inflammation that weakens the vessel walls until they leak blood into the air sacs [3][4].

Common autoimmune triggers include:

  • ANCA-Associated Vasculitis (AAV): A group of disorders that cause inflammation in small blood vessels throughout the body, often affecting the lungs and kidneys [1][3].
  • Anti-GBM Disease (Goodpasture’s): A rare condition where the body produces antibodies that specifically attack the “basement membrane” (the structural support) of the lungs and kidneys [5][6].
  • Systemic Lupus Erythematosus (SLE): A chronic autoimmune disease where the body’s immune system can attack many different organ systems, including the lung tissue [4][7].

These conditions are often treated aggressively with medications like rituximab or cyclophosphamide to “quiet” the immune system and stop the attack [1][4].

Non-Immune Causes: Drugs, Toxins, and Pressure

Non-immune DAH occurs without an autoimmune attack. Instead, the lung vessels are damaged by chemicals, infections, or physical stress [2][8].

  • Medications and Substances: Many substances can irritate the lungs or prevent blood from clotting correctly.
    • Anticoagulants: Blood thinners like Warfarin or Clopidogrel can increase the risk of bleeding [9][10].
    • Chemotherapy: Certain cancer treatments can have toxic effects on lung tissue [11][12].
    • Inhaled Toxins: Vaping products and illicit drugs like cocaine or fentanyl are recognized triggers for DAH [13][14].
  • Infections: While rare, certain infections like Mycoplasma pneumoniae or severe viral infections can damage the air sacs enough to cause bleeding [15][16].
  • Structural Heart Issues: If the heart has trouble pumping blood—specifically in conditions like mitral stenosis (a narrowed heart valve)—pressure can build up in the lung’s blood vessels [17][18]. This physical “back-pressure” can eventually force blood out of the vessels and into the air sacs [19][20].

Why the Distinction Matters

Distinguishing between these two types is the most critical step for your care team. Immune-mediated DAH usually requires powerful immunosuppressants to stop the body’s attack [4]. Non-immune DAH, however, is often managed by removing the trigger (such as stopping a drug) or treating the underlying heart or infection issue [2][8]. Your doctors will use blood tests, imaging, and sometimes a review of your heart health to determine which path is right for you.

Common questions in this guide

Is diffuse alveolar hemorrhage an autoimmune disease?
DAH itself is not a disease, but it can be caused by autoimmune diseases. In immune-mediated DAH, conditions like vasculitis or lupus cause the immune system to mistakenly attack the tiny blood vessels in the lungs, leading to bleeding.
Can medications or drugs cause bleeding in the lungs?
Yes, certain medications can trigger non-immune diffuse alveolar hemorrhage. Blood thinners, some chemotherapy drugs, and inhaled toxins can damage lung vessels or prevent normal blood clotting.
How does a heart problem lead to diffuse alveolar hemorrhage?
Structural heart issues, such as a narrowed mitral valve, can cause pressure to build up in the lung's blood vessels. This physical back-pressure can eventually force blood out of the vessels and into the lung's air sacs.
Why is it important to know if my DAH is immune or non-immune?
Knowing the exact cause dictates your treatment plan. Immune-mediated DAH requires powerful immunosuppressants to stop the body's attack, while non-immune DAH is typically managed by removing the trigger or treating the underlying heart condition.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Is my DAH classified as immune-mediated or non-immune, and how does that change my treatment plan?
  2. 2.Do I have markers for ANCA-associated vasculitis or Anti-GBM disease in my bloodwork?
  3. 3.Could any of my current medications, including over-the-counter supplements, have triggered this bleeding?
  4. 4.Have we checked my heart, specifically my mitral valve, to ensure the pressure in my lungs isn't causing the leak?
  5. 5.If this is an autoimmune condition, what are the chances of it recurring in the future?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (20)
  1. 1

    Diffuse Alveolar Hemorrhage in Autoimmune Diseases.

    Martínez-Martínez MU, Oostdam DAH, Abud-Mendoza C

    Current rheumatology reports 2017; (19(5)):27 doi:10.1007/s11926-017-0651-y.

    PMID: 28397125
  2. 2

    Clinical characteristics of patients with diffuse alveolar hemorrhage diagnosed by cytological examination of 1000 bronchoalveolar lavage samples.

    Prasad P, Gupta A, Nath A, et al.

    Sarcoidosis, vasculitis, and diffuse lung diseases : official journal of WASOG 2023; (40(1)):e2023004 doi:10.36141/svdld.v40i1.13413.

    PMID: 36975056
  3. 3

    [Diffuse alveolar hemorrhage in children].

    Jiang T, Li QB

    Zhongguo dang dai er ke za zhi = Chinese journal of contemporary pediatrics 2019; (21(9)):949-954.

    PMID: 31506159
  4. 4

    Systemic lupus erythematosus and diffuse alveolar hemorrhage, etiology and novel treatment strategies.

    Al-Adhoubi NK, Bystrom J

    Lupus 2020; (29(4)):355-363 doi:10.1177/0961203320903798.

    PMID: 32036761
  5. 5

    Splenic Infarcts and Pulmonary Renal Syndrome in a Young Patient with Double-Positive Anti-GBM and ANCA-Associated Vasculitis.

    Rajah FT, Alhabobi AA, Aloudah NM, et al.

    Saudi journal of kidney diseases and transplantation : an official publication of the Saudi Center for Organ Transplantation, Saudi Arabia 2021; (32(1)):240-244 doi:10.4103/1319-2442.318532.

    PMID: 34145139
  6. 6

    Beyond Infection and Lupus Flare: MPO-ANCA Microscopic Polyangiitis Causing Diffuse Alveolar Hemorrhage in a Patient With Systemic Lupus Erythematosus.

    Bocus A, Zaalouk TM, Chowdhury P, Nasim S

    Clinical case reports 2025; (13(12)):e71621 doi:10.1002/ccr3.71621.

    PMID: 41403984
  7. 7

    Risk factors for mortality of diffuse alveolar hemorrhage in systemic lupus erythematosus: a systematic review and meta-analysis.

    Jiang M, Chen R, Zhao L, Zhang X

    Arthritis research & therapy 2021; (23(1)):57 doi:10.1186/s13075-021-02435-9.

    PMID: 33593433
  8. 8

    Challenging Alveolar Hemorrhage Complicating Pneumonia After Liver Transplantation: A Case Report.

    Nugroho A, Lee KW, Kim H, et al.

    Transplantation proceedings 2018; (50(10)):4046-4049 doi:10.1016/j.transproceed.2018.06.017.

    PMID: 30577312
  9. 9

    Diffuse Alveolar Hemorrhage Associated with Warfarin Therapy.

    Kaya B, Yildiz I, Baha RM, et al.

    Case reports in medicine 2015; (2015()):350532 doi:10.1155/2015/350532.

    PMID: 26347781
  10. 10

    Diffuse Alveolar Hemorrhage after Clopidogrel Use.

    Onuk T, İpek G, Karataş MB, et al.

    Balkan medical journal 2016; (33(6)):719-720 doi:10.5152/balkanmedj.2016.151545.

    PMID: 27994935
  11. 11

    Diffuse Alveolar Hemorrhage With Avelumab Maintenance Therapy.

    Li S, Sharma N, Kazmierski D, et al.

    Cureus 2021; (13(6)):e15805 doi:10.7759/cureus.15805.

    PMID: 34306873
  12. 12

    Durvalumab-Induced Diffuse Alveolar Hemorrhage: An Autopsy Case Report.

    Kanaoka K, Ikebe S, Ihara S, et al.

    Case reports in oncology 2020; (13(2)):696-701 doi:10.1159/000507848.

    PMID: 32774259
  13. 13

    Apnea and Diffuse Alveolar Hemorrhage Caused by Cocaine and Heroin Use: A Case Report.

    Logan G, Robalino E, MacIntosh T, Ganti L

    Clinical practice and cases in emergency medicine 2020; (4(4)):537-539 doi:10.5811/cpcem.2020.7.48438.

    PMID: 33217266
  14. 14

    Cannabis Smoking-induced Diffuse Alveolar Hemorrhage.

    Alqahtani A, Ammari Z, Ramahi A, et al.

    Cureus 2019; (11(7)):e5089 doi:10.7759/cureus.5089.

    PMID: 31511809
  15. 15

    Severe pediatric Mycoplasma pneumonia as the cause of diffuse alveolar hemorrhage requiring veno-venous extracorporeal membrane oxygenation: A case report.

    Zhang X, Yu Y

    Frontiers in pediatrics 2022; (10()):925655 doi:10.3389/fped.2022.925655.

    PMID: 36683817
  16. 16

    A rare case of diffuse alveolar hemorrhage caused by acute mycoplasma pneumoniae pneumonia.

    Schmitz S, Arnon M, Martin C, et al.

    Journal of community hospital internal medicine perspectives 2021; (11(3)):366-369 doi:10.1080/20009666.2021.1906491.

    PMID: 34234908
  17. 17

    Pulmonary Venous Congestion and Pulmonary Hemorrhage in an Extremely Premature Neonate With a Large Patent Ductus Arteriosus and Closed Patent Foramen Ovale: A Case Report.

    Kappico JM, Siassi B, Ebrahimi M, Ramanathan R

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    PMID: 33349039
  18. 18

    Operable ventricular septal defect despite severe pulmonary hypertension and cyanosis!

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  19. 19

    Supra-systemic pulmonary hypertension after complicated percutaneous mitral balloon valvuloplasty: a case report and review of literature.

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    BMC anesthesiology 2021; (21(1)):258 doi:10.1186/s12871-021-01481-9.

    PMID: 34706655
  20. 20

    Unusual Pulmonary Manifestation in a Child With Congenital Mitral Stenosis: A Case Report.

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    PMID: 40225508

This page provides educational information on the causes of Diffuse Alveolar Hemorrhage (DAH). Always consult your pulmonologist or primary care team for an accurate diagnosis and personalized treatment plan.

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