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Diagnosis of diphtheria in adults
Last reviewed: 03.07.2025
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The diagnosis of diphtheria, regardless of the localization of the process, is based on the presence of a fibrinous film on the mucous membranes or skin, which has characteristic properties. In the common and toxic forms, the spread of plaque, the limits of the tonsils, swelling of the tonsils are of great diagnostic importance, and in toxic forms - swelling of the soft tissues of the neck.
To confirm the diagnosis, data from a microbiological study of smears from the affected surface (mucous membrane of the tonsils, nose, etc.) are important. After isolating the pathogen culture, its toxigenic and biological properties are determined.
[ Indications for consultation with other specialists
If necessary, consultations with the following specialists are recommended:
- neurologist (cranial nerve paresis, peripheral polyneuropathy);
- cardiologist (myocardial damage syndrome);
- resuscitator (respiratory disorders, multiple organ failure);
- otolaryngologist (diphtheria of the larynx, diphtheritic croup).
Indications for hospitalization
All patients with suspected diphtheria are subject to hospitalization and isolation.
Differential diagnosis of diphtheria
Differential diagnostics of oropharyngeal diphtheria is carried out with all diseases occurring with acute tonsillitis syndrome.
In practice, the most difficult differential diagnosis is between lacunar tonsillitis and localized diphtheria of the oropharynx.
The main differential diagnostic criteria for diphtheria:
- lacunar tonsillitis is characterized by the acute development of intoxication syndrome, while in localized diphtheria of the oropharynx, intoxication is weakly expressed;
- in case of lacunar tonsillitis, a more pronounced reaction of the tonsillar lymph nodes is revealed;
- fibrinous plaque on the tonsils is much more common in diphtheria;
- with tonsillitis, the pain in the throat is more intense, especially when swallowing;
- with tonsillitis, the mucous membrane of the oropharynx is brightly hyperemic; with localized diphtheria of the oropharynx, it is dull, with a grayish or bluish tint;
- Long-lasting (3-8 days) plaque after normalization of health and body temperature is characteristic of localized diphtheria of the oropharynx.
In addition to streptococcal and staphylococcal tonsillitis, one should keep in mind infectious mononucleosis, ulcerative necrotic tonsillitis of Simanovsky-Plaut-Vincent, angina-bubonic tularemia, syphilitic tonsillitis, and fungal infections of the oropharynx.
In toxic diphtheria, differential diagnosis is carried out with peritonsillar abscess, epidemic parotitis, phlegmon of the floor of the mouth (Ludwig's phlegmon), chemical burns, necrotic tonsillitis with agranulocytosis and acute leukemia.
Differential diagnostics of respiratory tract diphtheria is carried out with croup in ARVI: catarrhal phenomena, absence of aphonia are characteristic. In adults, bronchitis, pneumonia, asthmatic condition, foreign body in the larynx are often mistakenly diagnosed. Timely laryngoscopy is important.