It is an acute infectious disease caused by toxigenic strain of cornebacterium diphtheria.  It has following features –

  1. Formation of grayish or yellowish membrane.
  2. Marked congestion, edema or local tissue destruction.
  3. Enlargement of regional lymph nodes.
  4. Signs and symptoms of toxaemia.

Agent : Corynebacterium diphtheria.

Source of infection :   Cases – clinical and subclinical

Carriers – temporary and chronic

Infective material :     ·   Nasopharyngeal secretions

  • Discharges from lesions
  • Contaminated fomites.

Period of infectivity : 14-28 days from onset of disease.

Age : Children below 5 years of age.

Environmental factors : Winters

Mode of transmission :    ·   Droplet infection

  • Cutaneous lesions
  • Transmission of objects

Portal of entry :                   ·   Respiratory route

  • Cuts, wounds, ulcers, umbilicus, eye,

Genitalia, middle ear.

Incubation period : 2-6 days

Types of Diphtheria : Laryngo-tracheal, pharyngotonsillar, nasal and cutaneous.

  1. Throat shows erythema
  2. A membrane over entire tonsil, posterior pharynx, soft palate.
  3. Membrane is blue-white.
  4. Attempt to remove leads to bleeding.
  5. Edema of sub-mandibular area gives ‘bull neck appearance’.


Schick test



Diphtheria vaccine can be given singly or combined with pertusis and tetanus vaccine (DPT).


  • Early detection of cases and carrier.
  • Isolation of cases for 14 days.



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  • December 3, 2021