==pathogen==
*small gram positive bacilli
*''Corynebacterium diphtheriae''*droplet infection - human to human**congestion/over crowding is a risk factor*incubation 2-5 days (1-10 days) *''Corynebacterium ulcerans''**also produces toxin and causes clinical diphtheria**cattle**dogs and cats ==epidmiologyepidemiology==*mostly in younger children
==clinical picture==
*pseudomembrane
**both in pharynx and lower respiratory tracts
*anterior cervical lymphadenopathy
*Bull's neck
*laryngeal involvement leading to stridor and airway obstruction
*nasal discharge
**earlier serous, later bloody
*sometimes skin ulceration for long time
===complication===
*myocarditis
**due to heart block
**1-6 weeks after onset
**ST segment abnormalities in EKG
*Demyelinating peripheral neuritis
**10 days - 3 months after onset
**palatal palsy
**cranial nerve palsy
**limb weakness
**respiratory muscles weakness
==diagnosis==
*throat culture
**Hoyles Tellurite selective agar
**black colored colonies
*ELEK test
**to identify toxin production
**not all ''Corynebacterium'' produce toxin
**difficult and tricky
==treatment==
*Diphtheria antitoxin
**hose serum
**worldwide shortage is problem
*antibiotics
**benzyl penicillin
**macrolides
**14 days