10. Enlarged spleen (splenomegaly)
The enlargement of the spleen is closely related to inflamed lymph glands. It usually lasts for some weeks and disappears without being a problem, but some patients can experience a splenic rupture which is a severe complication of the disease. This symptom is also caused by other diseases.
11. Eyelid edema
It is considered a very specific symptom for infectious diseases, including the infection by EVB. In mononucleosis, it is always bilateral and only affects the upper-lid. This is an important difference with other infections that usually cause periorbital (upper and lower eyelids).