The lay term for glandular fever a.k.a. infectious mononucleosis.
A disease of young adults (the age group that's doing a lot of kissing of new partners), it's not a nice thing to have. Spread via saliva, the infectious agent is Epstein-Barr Virus (EBV).
The most common presenting complaints are a sore throat (nearly everyone), malaise and headache. The most common clinical signs are lymphadenopathy and fever (hence the "glandular fever"), followed by pharyngitis or tonsillitis. Splenomegaly and hepatomegaly are less common findings. In addition there sometimes is a rash which is described as faint, widely scattered, erythematous, and maculopapular.
The disease resolves spontaneously in most immunocompetent individuals within a week or two. Symptomatic treatment and antibiotic treatment of any secondary bacterial infections is the recommended way to go. The thing to remember is NOT to use amoxicillin or ampicillin as these antibiotics somehow make the rash much worse. Antiviral medications have so far proven to be rather useless in the treatment of this disease.
Those who have fought off this disease become lifelong carriers of EBV. They are usually not infectious unless they have a reactivation of the virus, which can happen sporadically. Previous infection with EBV is associated with an increased risk of Burkitt's lymphoma.