Erythema marginatum

Nature

Erythema marginatum is a type of erythema (redness of the skin or mucous membranes) involving pink rings on the torso and inner surfaces of the limbs which come and go for as long as several months. It is found primarily on extensor surfaces.

An association with bradykinin has been proposed in the case of hereditary angioedema.

Source: Wikipedia

Broader 
Aggravated by 
Type 
(G) Very specific problems