Differential diagnosis of a membrane over the tonsil

What it is

The differential diagnosis of a membrane over the tonsil is short: membranous tonsillitis, diphtheria and infectious mononucleosis.

How it presents

• Acute tonsillitis: the tonsils often meet in the midline and may be covered with a membrane. A white film that bleeds when you attempt to remove it, in a child who is pyrexial but otherwise well, is the bacterial one. Individuals who are systemically well are unlikely to have diphtheria.
• Diphtheria: a grey membrane, difficult to remove, on the tonsils and uvula, with low grade fever and tender enlarged cervical lymph nodes.
• Infectious mononucleosis: enlarged tonsils that meet in the midline, with petechial haemorrhages affecting the oropharynx and splenomegaly on systemic examination. A combination of pharyngitis and tonsillitis is often seen in glandular fever.

One unilateral picture does not belong to the membrane list at all: severe throbbing pain in the region of one tonsil after some days of sore throat, with fever and swelling around that tonsillar region, is quinsy, since unilateral swelling and fever is usually indicative of quinsy.

Acute pharyngitis sits behind all of these as the plain infective inflammation of the mucus membrane of the throat, with pain in the throat, dysphagia, malaise and fever, and on examination a congested pharynx with erythema, exudate and enlargement of the tonsils.