Girl presents with ear pain after swimming in brackish water
What’s your diagnosis?
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A 12-year-old girl presents to the guest columnist’s office with a red, painful right auricle. The onset was yesterday, and it is worse today.
There is no history of fever or injury to the ear, and the patient is otherwise in good health with her immunizations up to date for her age. More history reveals that the patient lives in southern California in an area that is connected to the Pacific Ocean via a narrow channel of brackish water that forms a pond near her home, and it happens to be her favorite place to swim. She had been swimming in the pond every day for 10 days before the onset of the ear pain.
On examination, she is alert and cooperative and shows no distress, with normal vital signs. Her examination shows only swelling and diffuse erythema confined to her right auricle (Figure 1), including the ear lobe, with forward displacement.
The pain was made worse by manipulation of the auricle. There were no breaks in the skin or lesions seen on the auricle, and as shown, there is slight, painless erythema over the mastoid area, with no swelling. The right tympanic membrane is clear, and her right ear canal is devoid of cerumen and a bit swollen with some mild erythema and pain of the skin in the canal, consistent with mild to moderate otitis externa (OE). A culture of the ear canal is pending.
What’s your diagnosis (most likely cause of the cellulitis)?
A. Staphylococcus aureus
B. Streptococcus pyogenes
C. Pseudomonas aeruginosa
D. Vibrio vulnificus
Answer and discussion:
This is a case of OE with associated periauricular cellulitis involving the auricle or pinna. By the numbers, the most common cause (about one in three) is Pseudomonas aeruginosa (choice C), especially in older children and adolescents, and was grown on the culture of the canal in this case. However, a wide range of gram-positive cocci and fungi are occasionally seen as the primary cause or mixed with other organisms. OE is commonly seen in the warmer months, when children are frequently swimming. This patient had been swimming daily for 10 days prior to the onset of the infection, resulting in some swelling and mild erythema of the skin of the canal. With the cerumen having been washed out, the protective layer was gone, giving environmental pathogen colonizers an opportunity to invade through microbreaks in the skin, setting the stage for the soft tissue infection that spread to the periauricular area and auricle. This case was empirically treated with oral ciprofloxacin, with good results (Figure 2).
Regarding Vibrio vulnificus, a highly virulent gram-negative rod that thrives in brackish water, there are three distinct forms that are typically seen:
- sepsis, which usually occurs when an immunodeficient patient eats contaminated seafood, like oysters;
- common gastroenteritis caused by a strain with an endotoxin; and
- localized, necrotizing wound infections, which can be life-threatening, occurring as a result of exposure of a skin injury to the organism.
Most cases in the United States are reported from the East Coast and Gulf Coast areas but have also been seen along the California coast. In warm, brackish waters, Vibrio species should be considered present. Isolated cases of OE with Vibrio species have very rarely been reported.
When dealing with periauricular and auricular cellulitis without OE, some important distinctions should be made. If associated with a break in the skin — even a simple insect bite or cutaneous herpes simplex lesion (Figure 3) — the bacteria will most likely be S. aureus.
If there is a sharp line of demarcation above the ear lobe as shown in Figure 3, beware of a deeper infection involving the perichondrium (perichondritis), which may impair the nutrient vessel to the cartilage, resulting in necrosis and a cosmetic deformity. If there is involvement of the ear lobe, the cellulitis is more likely superficial, as shown in Figure 4.
In that case, a patient with “ear ring” cellulitis was treated for a staph infection (Figure 5).
Also, if there is pain, erythema and swelling over the mastoid area, the diagnosis of mastoiditis is likely (Figure 6).
However, simple erythema over the mastoid area may occur with periauricular cellulitis, as in this vignette or as shown in Figure 7, which may be confusing and result in the erroneous diagnosis of mastoiditis. Stan L. Block, MD, FAAP, reported several such cases in the 2014 issue of Pediatric Annals.
Columnist comments
As usual, I would like to thank my old friend, Michael Cater, MD, FAAP, of Children’s Hospital of Orange County in Tustin, California, for contributing yet another interesting case to this column.
Regarding the words “pinna” and “auricle,” which term is most appropriate? Auricle is a late Middle English word derived from the Latin word auricula, meaning external ear. Pinna is derived from the Latin word for “wing” or feather. I suppose in the case of the cartoon character, Dumbo, who used his ears as wings with which to fly, the term pinna or pinnae would be most appropriate. Therefore, unless I see a child flying with the use of his external ears, I will use auricle rather than pinna from this point forward.
I hope your new year is one of good health and happiness. Please keep in touch and let me know if you have a good case that you would like to see appear in this column. If you have already sent me a case to potentially use but have not heard back, please let me know. My memory is not as sharp as it used to be.
Reference:
Block SB. Pediatr Ann. 2014;doi:10.3928/00904481-20140825-03.
For more information:
Brien is a member of the Healio Pediatrics Peer Perspective Board and an adjunct professor of pediatric infectious diseases at McLane Children's Hospital, Baylor Scott & White Health, in Temple, Texas. He can be reached at jhbrien@aol.com.