Chilblains


Chilblains, also known as pernio and chill burns are a medical condition that occurs when a predisposed individual is exposed to cold and humidity. Damage to capillary beds in the skin causes blood to perfuse into the nearby tissue too quickly, resulting in redness, itching, inflammation, and blisters. Chilblains can be reduced by keeping the feet and hands warm in cold weather, and avoiding extreme temperature changes.
COVID-19 may also cause chilblain-like symptoms, known as COVID toes, mostly in older children and adolescents. They tend to be delayed symptoms that are usually mild and disappear without treatment. The causality is controversial.
Chilblains can be idiopathic, but may also be a manifestation of another serious medical condition that must be investigated. Related medical conditions include Raynaud's disease, erythromelalgia, frostbite, and trench foot, as well as connective tissue diseases such as lupus or vasculitis.
In infants, chilblains together with severe neurologic disease and unexplained fevers occurs in Aicardi–Goutières syndrome, a rare inherited condition. Ulcerated chilblains are referred to as kibes.

Signs and symptoms

The areas most affected are the toes, fingers, earlobes, nose.
Chilblains caused by exposure to low temperatures usually heal within 7–14 days.

Prevention

Exposure

Treatment for the condition depends on its cause. Below are some common treatments for chilblains caused by exposure to low temperatures, though some may also apply to other sources of the condition.
The medieval Bald's Leechbook recommended treating chilblains with a mix of eggs, wine, and fennel root, and a modern home remedy is to put garlic on the chilblains. Neither of these remedies has been supported by scientific research.