Erythema nodosum is a disease of subcutaneous fat violation and skin vessels. This disorder meets quite often especially pregnant women suffer from this disorder. Symptom of erythema nodosum is emergence of small knots with a diameter from one to three cm. Often they arise on shins, but also can appear in zone of hips, buttocks and hands. As a rule, emergence of small knots is symmetric on both extremities. Small knots have a brilliant, thin and hot surface, are slightly higher than a level of skin surface and are painful during pressing. The warning of rash emergence at erythema nodosum are dray feelings in joints, the conditions of a general malaise and fever similar to states at flu.