Rhinovirus , adenovirus 5%, parainfluenza virus, Coxsacievirus<5%, coronavirus, echovirus,
herpes simplex virus<5%, Epistein-Barr virus, cytomegalovirus(CMV) & human immunodeficiency
virus.
C)Others causes of pharyngitis are
Oral thrush due to candidal species
Non-infectious cause include dry air, allergy/post-nasal drip, chemical injury, GERD,
neoplasm & endotracheal, intubation smoke inhalation, indoor heating sources & excessive air
conditioning.
Pathophysiology
1)In infectious pharyngitis: bacteria or viruses may directly invade the pharyngeal mucosa, causing a
local inflammatory response.
2)Others viruses such as rhinovirus cause irritation of pharyngeal mucosa secondary to nasal
secrection.
3) Streptococcal infections causes local invasion & release of extracellur toxins &
protease>inflammation. In addition M-protein are similar to myocardial sarcolemma antigen>
rheumatic fever& subsequent heart valve damage. Acute glomerulonephritis may result from
antibody-antigen complex deposition in glomeruli.
Clinical features
The classical history of sore throat , fever, chills, malaise, headaches, anorexia, abdominal pains as
well as history of exposure to known carriers is not always present.
GABHS features are suggestive : enlarged tonsils, pharyngeal erythema, tonsillar crypts containing
necrotic or purulent exudates, soft palate petechiae, cervical lymphadenopathy,fever, scarlet fever
rash(punctuate erythematous macules with reddened flexor creases & circumoral pallor), the so-
called sandpaper rash.
Specific viral infections have characteristic rash:
Viral pharynhitis associated with rhinitis(sneezing & rhinorrhoea) & cough .
Conjunctivitis more common in adenovirus infections.
Infectious mononucleosis is typically exudative with extensive false membrane;
Herpangina (usually Coxsackievirus A or herpes virus) is associated with papulovesicular lesion.
Comcomitant vesicles on the hands & feet are associated with Coxsackievirus (hand,foot& mouth
disease).
Tonsillopharyngeal /palatal petechiae are seen in GABHS & infectious mononucleosis.
Exudates does not differentiate viral & bacterial causes.