Wells syndrome. Light micrograph of a section through skin affected by Wells syndrome. There are many eosinophil white blood cells (dark pink) infiltrating the tissue. This rare condition, also known as eosinophilic cellulitis, causes itchy red inflamed lesions on the skin. Its cause is not known but in this case the reaction is to an insect bite. Magnification: x150 when printed at 10 centimetres wide. Human tissue.