• Complications of streptococcal pharyngitis are rare.
• Suppurative complications:
• Otitis media (most common).
• Acute sinusitis.
• Peri-tonsillar abscess (quinsy): there is a risk of airway compromise, or aspiration of pus from the abscess [Brook and Segal, 2006], or death due to vascular involvement [Swift, 1998]. Typically the person will have severe pharyngeal pain, fever, dysphagia, drooling, trismus, a 'hot potato' voice, swelling of the peri-tonsillar area with medial displacement of the tonsil, displacement of the uvula to the contralateral side, and a red and swollen soft palate [Drake-Lee, 1996; Swift, 1998; SIGN, 1999; Bisno, 2005; Millar et al, 2007].
• Peri-tonsillar cellulitis is the pre-abscess stage of peri-tonsillar abscess [Swift, 1998]. It presents with sore throat, fever, altered voice, and peri-tonsillar swelling, but uvula deviation and trismus are less likely to be present than in people with peri-tonsillar abscess [Millar et al, 2007].
• Parapharyngeal abscess occurs when the tissue space lateral to the pharynx becomes infected by the spread of organisms from the tonsils or the lower third molar teeth. It presents with sore throat and trismus, bulging of the lateral pharyngeal wall, medial displacement of the tonsil, swelling of the lateral pharyngeal wall, and tender swelling in the upper part of the neck [Swift, 1998; Stafford and Youngs, 1999]. It may compromise breathing or cause rupture of the carotid artery [Drake-Lee, 1996; Ludman, 1997; Shah and Har-El, 1999].
• Retropharyngeal abscess is most common in young children. It may occur following perforation of the pharynx by a foreign body or suppuration of a retropharyngeal lymph node. It presents in an infant or young child with sore throat, pyrexia, drooling, irritability, failure to eat or drink, and swelling of the posterior pharyngeal wall. The child assists breathing by hyperextension of the neck which is held rigid [Drake-Lee, 1996; Ludman, 1997; Swift, 1998; Shah and Har-El, 1999; Stafford and Youngs, 1999; Dhillon and East, 2006]. There may be difficulty breathing and there is a risk of inhalation of pus [Dhillon and East, 2006]. It is rare in adults, but when it occurs the person develops neck stiffness and tenderness, cervical lymphadenopathy, and pain and difficulty in swallowing [Swift, 1998].
• Mastoiditis.
• Suppurative cervical adenitis.
• Streptococcal pneumonia.
• Metastatic infection (e.g. brain abscess, endocarditis, meningitis, osteomyelitis or liver abscess).
• Streptococcal toxic shock syndrome.
• Lemierre disease (acute septicaemia and jugular vein thrombosis secondary to infection with Fusobacterium species). Lemierre disease, affects healthy young people, but is rare. It is characterized by acute onset, rigors, profound prostration, pain and swelling of the angle of the jaw, tenderness and induration along the sternocleidomastoid muscle, and swelling of the lateral pharyngeal wall with dysphagia and neck rigidity. The initial sore throat is severe and sometimes there is acute tonsillitis. Painful cervical lymphadenopathy is usually present. There is often metastatic spread of the infection to the lungs or less commonly to bones, joints, liver, brain, and heart valves [Eykyn, 2003a; Eykyn, 2003b; Chow, 2005].
• Non-suppurative complications (these are rare in developed countries, but are still a problem in developing countries):
• Rheumatic fever.
• Post-streptococcal glomerulonephritis.

[Bisno and Stevens, 2005; Del Mar et al, 2006; Kenealy, 2007]