What are Thread Veins? Thread Veins are commonly occurring skin blemishes that are very receptive to diathermy treatment. I meet many clients that are truly affected by the appearance of thread veins so for me this treatment supports not only the appearance of the blemish but the way in which my client feels as they can often be hard to conceal. Facial thread veins present as a permanent dilation of capillaries visible under rhe epidermis. They are also known as broken capillaries, thread veins and broken veins and usually found in more exposed areas of the skin like the nose, cheeks and chin. The generic term for all red veins,