Changes of coagulation parameters during erythema marginatum in patients with hereditary angioedema

Hereditary angioedema (HAE) with C1-inhibitor deficiency (C1-INH-HAE) is characterized by recurrent episodes of subcutaneous/submucosal edema, which may be preceded by erythema marginatum (EM) as a prodromal symptom. Our aim was to analyze the changes occurring in the parameters of the coagulation system during the development of EM and HAE attacks.

Eight C1-INH-HAE patients (1 male, 7 females, median age: 41.7 years) were studied. Blood samples were obtained from all patients (during symptom-free periods, EM, and HAE attacks), as well as from 20 sex- and age-matched healthy controls. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimer, Factor V, Factor VII, Factor X, Factor XI, and Factor XII levels were measured.

D-dimer levels were significantly lower, whereas aPTT was significantly prolonged in healthy controls vs. the values measured during the symptom-free period (p = 0.0497; p = 0.0043), in the presence of EM (p = 0.002; p = 0.0002), or during HAE attacks (p < 0.0001; p = 0.0002). We observed the following differences between samples taken during HAE attacks vs. in symptom-free periods: D-dimer levels were significantly elevated (p = 0.0391), while aPTT was significantly shorter during HAE attacks (p = 0.0159). D-dimer levels were significantly higher during EM than in symptom-free periods (p = 0.0078). Comparing the samples drawn during EM or during HAE attacks, there were no significant differences in the study parameters.

D-dimer levels were elevated during EM and this suggests that EM may be part of the HAE attack. Nevertheless, further research into the complement and kinin-kallikrein systems is needed in more patients for a better understanding of the pathomechanism of EM.