Chilblains and Raynaud phenomenon are usually not a sign of hereditary protein C and S deficiencies.

Hereditary protein C and S deficiencies are risk factors for thrombosis. They are associated with purpura fulminans and coumarin-induced skin necrosis. Recently, necrotic livedo of the extremities, severe chilblains and severe frostbite have been observed in protein C or S deficient patients. Our study was designed to evaluate the prevalence of cold-induced acral manifestations in patients with protein C or S deficiency. One-hundred-and-six patients with protein C or S deficiency and controls matched for sex and age were studied by questionnaire. Data included any history of acral manifestation possibly related to cold exposure, i.e. chilblains, Raynaud phenomenon, acrocyanosis and possible associated factors. Assessment of the diagnosis by a dermatologist was recorded. No difference was found in the prevalence of acral manifestations between patients and controls. This study suggests that protein C and S deficiencies are not risk factors for cold-induced acral manifestations.