Infectious Disease – 2 (Head & Neck Infections)

Still on our topic of Bugs & Drugs.  Today we’ll deal with a variety of unrelated infections at the top of the body, beginning with…


These are lumped together because they involve the same bacteria, namely those which colonize the upper respiratory tract.  They are, in order of frequency & importance:

  • Streptococcus pneumoniae (“Pneumococcus”)
  • Hemophilus influenza (“H. flu”)
  • Moraxella catarrhalis

Clinically, when we say “Otitis” or “Sinusitis,” we imply bacterial infection.  See recent posts (Ear Pain, and Nasal Congestion for dos & (mostly) don’ts of diagnosing these infections.

Traditionally, we treated for Pneumococcus & H. flu, ignoring the much-less-common Moraxella.  Drugs which used to work well included:

  • Amoxicillin
  • Cefuroxime
  • Macrolides
  • Doxycycline
  • Trimethoprim-Sulfamethoxazole (TMP-SMX)

Why the past tense?  There’s increasing prevalence of drug-resistant Pneumococcus out & around.  We’ll deal with this more when we discuss pneumonia, which is potentially fatal compared with otitis & sinusitis.  The best data for upper respiratory bacterial infections is in kids — high-dose amoxicillin (90 mg/kg/d) seems invariably successful, & nothing else has been studied as systematically.

“High-Dose” amoxicillin means (90 mg/kg/d).  However, experts often recommend up to 3 gm per day in heavy children, and the recent edition of Mandell’s text on I.D. endorses up to 2 gm q8h in adults.

The Infectious Disease Society of America (IDSA) recently decided that for Sinusitis, Amoxicillin-clavulanate should be first choice because of drug-resistant Pneumococcus.  However, it acknowledged the recommendation over Amoxicillin alone was “weak,” based on “low-quality” evidence.  It would seem that the same should be true for otitis (same pathogens), both adults & kids.  So go with either Amoxicillin plain, or combined with clavulanate.  The latter also covers Moraxella.

For pen-allergic patients, pick something else, which might be problematic.  Cefuroxime is the most logical, but the liquid pediatric prep is probably unpalatable.  Doxycycline is also a fair bet, but shouldn’t be used <8 yrs-old.  Levofloxacin will certainly work, but it’d be a shame to waste it on upper respiratory bacteria, & lose it for pneumonia (especially on over-diagnosed URIs).  Clindamycin covers Pneumococcus, but not H. Flu or Moraxella.

Macrolides & TMP-SMX run a greater risk of pneumococcal resistance, ≥30% in many areas.  The IDSA says that Macrolides & TMP-SMX shouldn’t be used.  So no more “Z-Packs,” please.  Not for sinusitis, & logically not for otitis either.  Click for the IDSA Guidelines.

My main peeve about all this is how often I see otitis & sinusitis over-diagnosed, & antibiotics prescribed.  So cynically-speaking, I’m happy for others to throw azithromycin around as drug-of-choice here, because I’ve given up on its usefulness.  I do write for it occasionally — when a patient insists they need an antibiotic, & I’m too busy to argue.

Clink link for doses of common antibiotics.


Pseudomonas aeruginosa & Staph aureus are the main pathogens infecting the external ear canal, though commensual colonizers also play a major role.  Many infections appear polymicrobial, but treating for Pseudomonas & Staph will cover everything else too.  See our posting Ear Pain for clues regarding diagnosis.  Treatment is always empiric.

Topical therapy works whenever infection is localized to the canal itself.  The available preparations seem to be:

  • Ciprofloxacin or Ofloxacin otic drops
  • Neomycin + Polymyxin + hydrocortisone (Cortisporin®)
  • Gentamicin or Tobramycin ophthalmic drops (no otic formula available)
    • Tobramycin + dexamethasone ophthalmic suspension

There’s no good evidence that adding a steroid helps.  Neomycin-containing preparations are notorious for causing contact dermatitis, but may be cheapest.  Ofloxacin may be available generically, ciprofloxacin maybe not.  Ophthalmic preparations are more expensive than otic ones.

Drops may work better if a wick is inserted [hard to do at home].  If nothing else, be sure somebody helps the patient apply the drops.  They should then remain lying ear-up for 20-30 minutes so solution seeps into the canal.

In severe cases of otitis externa, when a cellulitis extends around the external tragus, systemic antibiotics are necessary.  I’ve gotten by with oral anti-staphylococcal treatment plus otic solution.  Oral ciprofloxacin covers Pseudomonas too, but not methicillin-resistant staph (MRSA).  Diabetics, or anyone febrile, should be admitted for IV Tx.


The vast majority conjunctivitis is viral; DON’T treat with antibiotic drops.  As we mentioned in our posting Red Eye – 2, only diagnose bacterial conjunctivitis if there’s yellow, white, or green pus that exudes continually from a non-painful eye (usually unilateral).  Wipe it away, & more appears within minutes.

Like in the upper respiratory tract, target bacteria are also Pneumococcus, H. Flu & Moraxella, plus Staph (S. aureus).  Topical preparations invariably employ high levels of antibiotics never tolerably orally, so virtually everything works.

However, AVOID anything with Neomycin, because 10% to 30% of people may develop a hypersensitivity reaction.  That’s often worse than the conjunctivitis (& of course patients then tend to apply drops more aggressively).  Alternatives include:

  • Erythromycin ointment
  • Polymyxin-Trimethoprim drops (Polytrim®)
  • Azithromycin drops
  • Fluoroquinolone drops

The last two are expensive.  Sulfonamide drops are often sensitizing.  My favorite is Polymyxin-Trimethoprim, since those antibiotics aren’t used for anything else.

For serious, sight-threatening eye infections (e.g. keratitis), drops have to be applied every 15 minutes.  You can get by Q.I.D. for bacterial conjunctivitis; maybe q4h would be better.

As noted, most conjunctivitis is viral; unfortunately, “pink-eye” is a reason for exclusion from school (& ostracism by peers).  It’s nothing more than a “common cold in the eye,” but that never seems to console anybody.  I remember a pediatrician once giving parents an antibiotic preparation for their child’s viral infection, & saying it was OK to go to school after 24 hrs.  I don’t agree; it’s MUCH BETTER to simply lie.  If it’s a virus, give anti-histamine drops, & tell parents to say the kid’s “being treated.”


The only bacteria to infect the throat is Steptococcus pyogenes, i.e. Lancefield’s Group A Beta-Hemolytic Strep (GABHS), or more simply, “Strep”.  Actually, groups C and G can also cause a self-limiting pharyngitis, but they a) respond to the same antibiotics, and b) don’t cause rheumatic fever.

Prevention of rheumatic fever is the only rationale for treating Strep, since it gets better on its own (preventing contagion is another; Strep can also cause glomerulonephritis, but treatment doesn’t avoid it).  Rheumatic fever is real rare nowadays, and we have a 9-day margin to treat.  So best management is to obtain a culture (not rapid strep); but most people want a same-day answer.  Testing can’t distinguish infection from colonization — tough luck.

Treatment: Penicillin [250 mg QID x10 d in adults].  Not amoxicillin or anything else.  If Pen-allergic, a cephalosporin, macrolide, or clindamycin is fine.  Not TMP-SMX, doxycycline, or ciprofloxacin, since they don’t cover Strep.

A single [painful] IM dose of Benzathine penicillin, 1.2 million units, works just fine also.  This is the treatment of choice for anyone’s who’s had rheumatic carditis.  NEVER give procaine penicillin [looks the same], or procaine-benzathine combination products [no logical rationale].  There was an outbreak of mistreated syphilis in Los Angeles once, from clinicians who didn’t understand [or didn’t read the label].

Of course, most pharyngitis is viral.  See our posting Sore Throat-1 for diagnosing symptoms on Day 1-3, and Sore Throat-2 for longer syndromes.


These comprise a diverse group of entities including:

•  Tooth  infections                 •  Gingivitis                 •  Peritonsillar abscess
•  Deep oral infections           •  Human Bites            •  Lung abscesses

The culprit bugs are always normal oral anaerobic bacteria.  These do NOT include Bacteroides fragilis, common among anaerobic intestinal flora.

Therefore, plain-old penicillin is the drug-of-choice for anaerobic infections above the diaphragm.  If treating as an out-patient, give Pen V K 500 mg Q.I.D.

Sort of.  Some strains of oral anaerobes produce beta-lactamases, thus potentially destroying our penicillin.  So maybe we should use Amoxicillin-clavulanate (Augmentin®) or Clindamycin.  But giving these too often (especially Clinda) runs a risk of causing intestinal C. difficile.

So I personally stick with Penicillin, especially for the all-too-common situation of an infected tooth needing a root-canal or extraction (Pen + narcotic for 5 days, with explicit instructions to see a dentist, “no refills of either from me”).

For Pen-allergic patients, go with Clindamycin or Metronidazole.  Consider these also for more severe oral infections, like a possible peritonsillar abscess you think you can abort medically without an I&D.


The differential for this is broad: both common & uncommon infections, & non-infectious causes including malignancy.  But first, a definition: lymphadenitis means one single acute, painful, tender node; it’s different from lymphadenopathy.  The latter, if tender & acute, is regional or even somewhat generalized (e.g. posterior cervical nodes with mono or primary HIV).  A single non-painful, non-tender node is usually more chronic, though a patient may have just discovered it.

Here we’re only going to discuss acute focal lymphadenitis, which is undoubtedly infectious.  We’ll assume you’re not dealing with an actual abscess.  And we’re going to assume the patient is afebrile & does not look ill.  Otherwise, they may need blood cultures & a fine-needle aspiration for definitive diagnosis [ruling out things like plague, tularemia, etc).

If there’s a history of exposure to kittens, look for a pustule somewhere that would drain into the swollen node.  Find it, & you’ve got Cat-Scratch Disease, due to Bartonella.  But this usually occurs on extremities, not head-&-neck [our current topic].

Submandibular and submental nodes (under the jaw bone) invariably mean oral infections, which are anaerobic.  Treat how we just discussed above, & send to a dentist.  Otherwise, the bugs are the same as for Skin & Soft Tissue Infections: Staphylococcus aureus (“Staph”) & Streptococcus pyogenes (Group A beta-hemolytic, aka “Strep”).

For anterior cervical adenitis, percuss the nearby teeth just to be sure there’s no occult dental infection (tap on them with a tongue blade).  Then, assuming there’s no sore throat to suggest Strep, target Staph primarily:

  • MRSA in the community: TMP-SMX, Doxycycline, maybe Clindamycin
  • MRSA not a concern:  Dicloxicillin, Cephalexin, or Amoxicillin-Clavulanate

That’s it for Head & Neck Infections.  Other I.D. postings address the variety of bacteria that infect Skin & Soft Tissue, the Lower Respiratory Tract, and organs Below the Diaphragm (UTIs, PID, & diverticulitis).

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