Diphtheria early symptoms: what to know

The first symptoms can resemble an ordinary throat infection. Pain when swallowing, reduced appetite, feeling unwell and a low-grade temperature may appear. A grey or white membrane can form over the tonsils or throat and may bleed if disturbed, so do not try to scrape it away. Neck swelling can become noticeable as the illness progresses. Diphtheria is caused by bacteria that can release a toxin, which means a person can become seriously ill even when the early fever is not dramatic. A sore throat has many possible causes; its presence alone does not establish diphtheria.

Arrange urgent medical assessment if these symptoms follow close contact with a suspected case, or if a throat membrane or marked neck swelling appears. Avoid close contact, sharing cups and utensils, and handling respiratory secretions until a clinician gives advice. Cover coughs, wash hands, and tell the clinic before arriving so staff can reduce exposure to others. Testing and treatment may involve throat samples, antibiotics and other clinician-directed care; read more about [Antibiotic Treatment](/treatments/medical-management/antibiotic-treatment/). Vaccination helps prevent diphtheria, but it does not replace assessment of new symptoms. See [Childhood Immunisation](/treatments/preventive-care-and-vaccination/childhood-immunisation/) for routine prevention.

Seek emergency help for difficulty breathing, noisy breathing, inability to swallow fluids, drooling, rapidly increasing neck swelling, bluish lips, faintness or unusual weakness. These signs can indicate airway narrowing or serious toxin effects. Do not wait for a high fever before getting help. If symptoms are milder but diphtheria is possible, contact a healthcare service promptly and mention any exposure and vaccination history.

Ask whether throat testing is needed, whether close contacts require assessment or preventive treatment, and which warning signs should prompt emergency care. You can also ask when it is safe to return to school or work and whether your vaccination record needs updating. For background on throat discomfort, see [Sore Throat](/symptoms/sore-throat/).