Herpangina

Herpangina is an acute viral infection of children characterised by sudden fever and painful vesicles and ulcers on the posterior oropharynx (soft palate, anterior tonsillar pillars, uvula and tonsils). Not to be confused with herpes (it is not caused by herpes simplex virus).

• Cause: group A coxsackieviruses (A2 to A6, A8, A10, A22) most often; also coxsackie B, echoviruses, enterovirus 71.
• Age 3 to 10 years most affected (also infants and young adults); summer and autumn peak in temperate zones; incubation 3 to 6 days; spread by faecal oral route and respiratory droplets.
• Self-limited illness lasting 3 to 7 days. Main complications: dehydration, febrile seizures; rarely aseptic meningitis, myocarditis.

• Abrupt high fever (38.5 to 40 C, up to 4 days), sore throat, odynophagia, dysphagia, drooling in infants, refusal to eat or drink, vomiting, headache, myalgia, neck pain, malaise.
• Pharyngeal examination: 1 to 5 mm grey white vesicles with an erythematous halo that rupture to shallow ulcers (usually 2 to 6 in number, up to 20) on the soft palate, uvula, tonsillar pillars and posterior pharynx; anterior mouth and tongue spared (unlike hand, foot and mouth disease); cervical lymphadenopathy is mild.
• Tonsils may appear red; no pus or exudate in uncomplicated cases.
• Red flags: inability to drink with dehydration, persistent fever beyond 5 days, stridor, trismus, muffled voice, neck stiffness, drowsiness, seizures, cardiac symptoms, immunocompromise, age under 3 months, signs of bacterial tonsillitis or peritonsillar abscess.

• Clinical diagnosis based on the typical posterior pharyngeal vesicles in a febrile child.
• Throat swab for rapid streptococcal antigen or culture if exudative tonsillitis is possible (the two can coexist).
• Enterovirus PCR from throat swab or stool only if severe or atypical.
• Differentials: herpetic gingivostomatitis (anterior gums involved, vesicles on lips and anterior mouth; HSV), hand, foot and mouth disease, streptococcal pharyngitis, infectious mononucleosis, aphthous stomatitis, diphtheria, tonsillitis.

• Supportive: encourage frequent small amounts of cool fluids (cold water, milk, ice lollies, diluted juice); soft, bland, non-acidic foods; avoid hot, spicy or acidic drinks; oral rehydration solution for mild dehydration.
• Antipyretic and analgesia: paracetamol 15 mg/kg orally every 4 to 6 hours (maximum 4 doses in 24 hours); ibuprofen 5 to 10 mg/kg orally every 6 to 8 hours with food (age over 3 months, adequate hydration).
• Throat soothing for older children: warm salt water gargles, lozenges with benzydamine (age over 6 years); avoid topical lidocaine in young children and choline salicylate gels under 16 years.
• Antibiotics are not indicated; antivirals (aciclovir) are not effective as the aetiology is enteroviral (reserve aciclovir for confirmed herpes gingivostomatitis: 15 mg/kg orally five times daily for 5 to 7 days in children over 1 month).
• Admit for dehydration not corrected by oral fluids (intravenous isotonic fluid bolus 10 to 20 mL/kg then maintenance), neurological or cardiac complications.
• Hygiene: hand washing, avoiding sharing utensils; keep the child at home while febrile.
• Recovery in 5 to 7 days; review if fever persists more than 5 days or the child cannot drink.