National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Systemic capillary leak syndrome


Other Names:
SCLS; Clarkson disease; Capillary leak syndrome; SCLS; Clarkson disease; Capillary leak syndrome; Capillary leak syndrome with monoclonal gammopathy; Periodic systemic capillary leak syndrome See More
Systemic capillary leak syndrome (SCLS) is a condition in which fluid and proteins leak out of tiny blood vessels, into surrounding tissues. This can result in dangerously low blood pressure (hypotensison), hypoalbuminemia, and a decrease in plasma volume (hemoconcentration).[1][2] Initial symptoms may include fatigue, nausea, abdominal pain, extreme thirst, and sudden increase in body weight. Episodes of SCLS vary in frequency, with some people having one episode in their lifetime, and others having several per year. The severity also varies, and the condition can be fatal.[2]

In many cases the cause is not known (idiopathic SCLS).[2] Some people with SCLS report having had an infection (such as a virus) before the episode.[3] Some cases of capillary leak are associated with various conditions of the heart, kidney, or liver.[2] Treatment during an episode may involve stabilizing the airway and breathing, and infusion of fluids, medications, or blood products. Periodic infusions or the use of certain medications may be used to prevent future episodes.[2]
Last updated: 7/31/2017

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Leukocytosis
Elevated white blood count
High white blood count
Increased blood leukocyte number
[ more ] 		0001974
Pedal edema
Fluid accumulation in lower limbs
Lower leg swelling
[ more ] 		0010741
30%-79% of people have these symptoms
Abdominal pain
Pain in stomach
Stomach pain
[ more ] 		0002027
Diarrhea
Watery stool
0002014
Fatigue
Tired
Tiredness
[ more ] 		0012378
Hypotension
Low blood pressure
0002615
Myalgia
Muscle ache
Muscle pain
[ more ] 		0003326
Pancreatitis
Pancreatic inflammation
0001733
Pulmonary edema
Excess fluid in lungs
Wet lung
[ more ] 		0100598
Rhinorrhea
Runny Nose
0031417
Weight loss 0001824
5%-29% of people have these symptoms
Abnormal renal tubule morphology 0000091
Arrhythmia
Abnormal heart rate
Heart rhythm disorders
Irregular heart beat
Irregular heartbeat
[ more ] 		0011675
Cardiorespiratory arrest 0006543
Cough
Coughing
0012735
Multiple myeloma 0006775
Myocarditis
Inflammation of heart muscle
0012819
Oliguria 0100520
Pericarditis
Swelling or irritation of membrane around heart
0001701
Pleural effusion
Fluid around lungs
0002202
Renal insufficiency
Renal failure
Renal failure in adulthood
[ more ] 		0000083
Venous thrombosis
Blood clot in vein
0004936
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Last updated: 7/1/2020
Systemic capillary leak syndrome is diagnosed based on physical examination, laboratory tests, and recurrence of symptoms. Recurring episodes are associated with monoclonal gammopathy in the majority of patients (when an abnormal immunoglobin protein is found in the blood). The diagnosis is supported by ruling out other illnesses with similar symptoms, including secondary capillary leak syndrome or abnormally low levels of protein in the blood (hypoproteinemia).[4][2][5]
Last updated: 2/3/2017
There is currently no cure for systemic capillary leak syndrome (SCLS). Treatment for SCLS during an episode is mainly supportive, aiming to stabilize symptoms and prevent severe complications.[3] This may involve stabilizing the airway and breathing, taking certain medications, and/or intravenous (IV) infusion of fluids, medications, or blood products.[2] Some have suggested that IV fluids are not recommended because it may worsen swelling (edema) or increase the risk for other complications.[4] Once a person begins to recover, diuretics are almost always required.[2]

Periodic infusions or the use of certain medications are used to try to prevent future episodes (prophylactic therapy). Having monthly infusions of intravenous immune globulin (IVIG) has been suggested.[2] A study published in 2017 found that preventive treatment with IVIG was the strongest factor associated with survival in people with SCLS.[5] Those who do not improve with IVIG or who cannot tolerate the therapy may have success with theophylline and terbutaline.[2]

Research into how SCLS develops and factors that affect its course are underway, in hopes that a better understanding of SCLS will lead to more effective treatment options and a lower mortality rate.
Last updated: 7/31/2017

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes sepsis, anaphylaxis, any other cause of capillary leakage and inferior vena cavainterruption (see this term). Chronic cases might be misdiagnosed as Gleich syndrome, venous stasis, protein-losing enteropathy and nephrotic syndrome.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Systemic capillary leak syndrome. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • The Research Portfolio Online Reporting Tool (RePORT) provides access to reports, data, and analyses of research activities at the National Institutes of Health (NIH), including information on NIH expenditures and the results of NIH-supported research. Although these projects may not conduct studies on humans, you may want to contact the investigators to learn more. To search for studies, enter the disease name in the "Text Search" box. Then click "Submit Query".

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Social Networking Websites

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • The National Cancer Institute glossary of terms includes an entry for capillary leak syndrome with monoclonal gammopathy. Click on National Cancer Institute to view the definition.
  • Mayo Clinic has an information page on Systemic capillary leak syndrome.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • MeSH® (Medical Subject Headings) is a terminology tool used by the National Library of Medicine. Click on the link to view information on this topic.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Systemic capillary leak syndrome. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • Is there a full and final cure for systemic capillary leak syndrome? See answer


  1. Dictionary of Cancer Terms: capillary leak syndrome. National Cancer Institute (NCI). http://www.cancer.gov/dictionary?CdrID=426421. Accessed 9/11/2014.
  2. Rajesh A. Idiopathic systemic capillary leak syndrome. UpToDate. May 20, 2016; http://www.uptodate.com/contents/idiopathic-systemic-capillary-leak-syndrome.
  3. Druey KM, Parikh SM. Idiopathic systemic capillary leak syndrome (Clarkson disease). J Allergy Clin Immunol. December 22, 2016; http://www.sciencedirect.com/science/article/pii/S0091674916324605.
  4. Amoura Z. Systemic capillary leak syndrome. Orphanet. November 2012; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=188.
  5. Pineton de Chambrun M, Gousseff M, Mauhin W, et al. Intravenous Immunoglobulins Improve Survival in Monoclonal Gammopathy-Associated Systemic Capillary-Leak Syndrome. Am J Med. June 9, 2017; https://www.ncbi.nlm.nih.gov/pubmed/28602874.