Systemic capillary leak syndrome is a rare disorder characterized by repeated flares of massive leakage of plasma from blood vessels into neighboring body cavities and muscles. This results in a sharp drop in blood pressure that, if not treated, can lead to organ failure and death.

Also called Clarkson's disease, this condition can be mistaken for severe reactions to widespread infections (septic shock) or severe allergic reactions (anaphylactic shock). Attacks may be triggered by an upper respiratory infection or intense physical exertion. The frequency of attacks can range from several a year to a single instance in a lifetime.


Attacks of systemic capillary leak syndrome are often preceded by one to two days of one or more nonspecific symptoms that may include:

  • Irritability
  • Fatigue
  • Abdominal pain
  • Nausea
  • Muscle aches
  • Increased thirst
  • Sudden increase in body weight

As the fluid leaks out from the bloodstream, blood volume and blood pressure drop. This can starve tissues in the kidneys, brain and liver of the oxygen and nutrients they need for normal function.

Systemic capillary leak syndrome care at Mayo Clinic

Nov. 14, 2020
  1. Systemic capillary leak syndrome. Genetic and Rare Diseases Information Center. https://rarediseases.info.nih.gov/diseases/1084/systemic-capillary-leak-syndrome. Accessed Oct. 12, 2017.
  2. Aneja R. Idiopathic systemic capillary leak syndrome. https://www.uptodate.com/contents/search. Accessed Oct. 12, 2017.
  3. Druey KM, et al. Idiopathic systemic capillary leak syndrome (Clarkson disease). Journal of Allergy and Clinical Immunology. 2017;140:663.
  4. Kapoor P, et al. Idiopathic systemic capillary leak syndrome (Clarkson's disease): The Mayo Clinic experience. Mayo Clinic Proceedings. 2010;85:905.
  5. Brown AY. Allscripts EPSi. Mayo Clinic, Rochester, Minn. Aug. 30, 2017.


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