At high temperatures, all superficial blood vessels expand - including varicose veins. This can cause or intensify already existing swelling of the limbs. Swelling in a short period of time can lead to inflammation of the skin and subcutaneous tissue, which appears as a painful hardening in the place of overheated body and therefore red skin. Inflammation may cause the appearance of permanent brown discoloration on the skin, allergies - itchy pimple-like rash and oozing, serous vesicle, and may also lead to venous ulcers - extensive, oozing and painful wounds on the lower legs. This may take many months up to years to heal. In addition, summer is the time for holiday trips, long journeys by plane or car, i.e. long periods of standing without moving. This position causes blood to stagnate and can lead to thrombosis.