title: Hereditary angioedema associated with heterozygous factor V Leiden mutation in a patient with Purpura fulminans.
abstract: BACKGROUND
  Hereditary angioedema (HAE) is an autosomal dominant, quantitative or functional defect of the C1 esterase inhibitor. The main role of the C1 esterase inhibitor is to regulate the activation of the complement system, the contact phase of the intrinsic coagulation system. On the other hand, factor V Leiden is the most common cause of primary and recurrent venous thromboembolism and displays a strong interaction with oral contraceptives. Here we report the case of a patient with HAE associated with the factor V Leiden mutation who had purpura fulminans when put on an oral contraceptive therapy.
  
  
  METHODS
  A 42-year-old woman presented to the emergency room with a history of livid skin changes on her legs during a flight. On physical examination, the vital signs were normal, but there were edemas in her legs. The livid skin changes tended to increase, eventually leading to skin necrosis on the next day. She had a history of a similar episode two months before and experienced both episodes of necrotic skin lesions just after she had been put on a hormone replacement therapy due to irregular menstruations. She also had a history of recurrent angioedema attacks since her childhood, triggered by stress and physical stimulants such as pressure and heat. Subsequent investigations revealed heterozygous factor V mutation, activated protein C resistance and reduced C1 inhibitor levels.
  
  
  CONCLUSIONS
  Thrombosis is a multifactorial disease. The coexistence of multiple hereditary and acquired factors eases its occurrence. Women with HAE should be screened for the factor V Leiden mutation before pregnancy or the start of a hormone replacement therapy.
authors.affiliation: Department of Chest Diseases, Adult Allergy Unit, Hacettepe University School of Medicine, Ankara, Turkey. scelikel@gmail.com
authors.forename: S
authors.initials: S
authors.lastname: Celikel
authors.forename: Y
authors.initials: Y
authors.lastname: Buyukasik
authors.forename: G
authors.initials: G
authors.lastname: Karakaya
authors.forename: A F
authors.initials: AF
authors.lastname: Kalyoncu
mesh_terms: D000328:Adult; D000799:Angioedema / Q000235:genetics*; D005165:Factor V / Q000235:genetics*; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects; D006801:Humans; D011695:IgA Vasculitis / Q000235:genetics*; D017354:Point Mutation
chemical_list: C095381:factor V Leiden; D005165:Factor V