Teen pseudo-modesty and pseudo-rash decision

January 2005

We pediatricians encounter a multitude of rashes and infections that often defy routine diagnosis. Even when the correct medical diagnosis can be deduced quickly, the etiology of the offending pathogen is harder to ascertain than the medical textbooks would have us to believe. Furthermore, pediatric patients are frequently scared of our “necessary” culture techniques, and the family may be overwhelmed by the cost of our procedures.

Even worse, one must diagnose using a combination of clinical acumen, medical sixth sense and “even-a-blind-hog-finds-a-nut-once-in-a-while” luck.

On a frosty winter day, a 12-year-old early pubescent girl enters the office complaining of an itchy, burning rash scattered over her trunk and legs (Figure 1). She is afebrile and otherwise healthy and denies any constitutional symptoms.

It is with much cajoling that I convince her to remove most of her clothing for me to visualize the full extent and actually determine the type of rash she has acquired. I explain that I am “a really good doctor, but I have not yet acquired the x-ray vision of Superman.” She seems to comprehend my limitations. Slowly, behind the curtain she removes her shirt and places on our most deluxe stylish paper gown.

I notice the multiple papules on her trunk, which have a whitish central pustule in a few lesions. Could there be more?

Now, God forbid, I must ask her to remove her pants and to tie one of our ever-fashionable paper robes. More apologies for my human limitations and lack of super-vision!

I notice a few alarming lesions on her buttocks and her posterior thigh area, some of which have blossomed into a semblance of an early erythematous abscess (Figure 2).

“Have you used any new detergents, been exposed to chickenpox or other viruses, developed any blisters on the hands or feet, any sore throat?”

My symptom review gets a negative response. “But two of my friends have developed an itchy rash this week. We spent the night together last week.”

Now the specter of the mighty itch is clawing at my cerebrum. But I notice she has no lesions on her arms, hands or below her knees. No dog or cat exposure either. Perhaps she traumatized one of the papules enough to secondarily infect it with methicillin-resistant Staphylococcus aureus (MRSA)? The lesions are both painful and pruritic. They don’t itch more at night.

Mom chimes in: “The girls were all in the hot tub last week. Could that have anything to do with it?”

Ah, the wintertime enigma — hot tub folliculitis! Her rash is found mostly in the bathing suit area, and the posterior thigh lesions may have originated from sitting on the bench. Still, there is ubiquitous MRSA in the area. “Do you mind if I obtain a culture of the worst lesion, which has some pus in it?” A few tears, but the girl handled it rather well.

The next week, a 4-year-old girl presents with a nonspecific papular pruritic rash (Figure 3). She has no other symptoms and review of symptoms for rash turns up nothing. “By the way, have you been exposed to a hot tub recently?” Affirmative. Bingo! We discuss the risks, duration and degree of symptoms for untreated Pseudomonas hot tub folliculitis vs. the risks and benefits of empiric therapy with oral ciprofloxacin. A culture of one of the pustules is performed.

Nail puncture wounds

The 8-year-old boy was playing in the barn when he stepped on a nail. He was wearing tennis shoes. The next day, the plantar aspect of the foot reveals the inflamed, tender puncture site and an adjoining erythematous streak ascending the arch of the foot (Figure 4). He can move each of his toes and tendons without pain, and no bony tenderness in his foot can be elicited.

Of course, this child is probably infected with Pseudomonas, which if left untreated can blossom into tenosynovitis or osteochondritis. Having observed more than 30 nail puncture wounds in my career, I’ve found that one can rarely accurately ascertain the true depth of the puncture. My foot was punctured by a nail 15 times in my less-than-illustrious construction career. (Much safer for me to be a doctor!) Each puncture wound hurt terribly; I could never estimate the depth. Luckily, none ever were infected.

Pseudomonas is widely documented to cause hot tub folliculitis, as was the case in both my patients. As you can see from the figures, the lesions are rather nonspecific and easily could pass for an enteroviral, scabies or staphylococcal folliculitis. Like success in real estate, location, history and timing are the keys to diagnosis!

In general, hot tub lesions consist of pustules, pruritic papules or tender erythematous nodules, which develop within two to five days of hot tub exposure. Sometimes fever, malaise and lymphadenopathy, and rarely septicemia or metastatic foci, can develop, especially in the immunocompromised. But remember, MRSA or other pathogens may be the offending pathogen in any skin abscess, lymphangiitis or folliculitis.

In the past, the only real option even for outpatient Pseudomonas infections was parenteral therapy twice or thrice daily with antibiotics such as ceftazidime. Can we now consider empirically initiating early therapy with a fluoroquinolone for hot tub folliculitis or an uncomplicated infected nail puncture wound? Ciprofloxacin is considered safe enough for children with complex urinary tract infection. Should we obtain a culture and then consider waiting three or four days for the results to target therapy? Or should we begin therapy with cephalexin or even trimethoprim-sulfamethoxazole to provide coverage for S. aureus or even MRSA, but which merely provides placebo coverage for Pseudomonas?

We are all aware of the theoretical hazards of quinolone-induced arthropathy in the beagle puppy. But this has not been documented in the limited pediatric prescribing and research of the quinolones in the United States.

However, prescribing quinolones in ambulatory children requires the following: high probability of Pseudomonas or a highly resistant enterobacteria, the lack of a reasonable oral antibiotic alternative, reasonably informed consent and parental awareness of potential and theoretical adverse events.

Then, for hot tub folliculitis, the clinician must assess whether the dermatologic infection is severe enough to warrant therapy. Pediatric infectious disease textbooks recommend the use of topical astringents (acetic acid), gentian violet or topical antibiotics like gentamicin or polymyxin B. These obnoxious dermatologic lesions can spontaneously resolve over one to two weeks — with or without topical therapy. Interestingly, most practitioners initiate therapy for hot tub folliculitis with cephalexin or a macrolide; strangely, the lesions also disappear within one to two weeks.

However, I have been quite impressed with the rapid (two days) resolution in most cases of either hot tub folliculitis or less serious puncture wounds treated with oral ciprofloxacin.

Initial choices for hot tub folliculitis: Ignore, topical antibiotics, astringents, empiric oral antistaphylococcal antibiotics, empiric oral anti-pseudomonal antibiotics, pretreatment culture, culture of antibiotic failures. Whew, the choices are daunting!

I believe that any significant hot tub folliculitis that presents or evolves into systemic signs, cellulitis, lymphadenopathy, abscess, or hot, painful and erythematous papules should be treated with oral ciprofloxacin for five to seven days, which will achieve serum concentrations commensurate with its parenteral form. Before initiating therapy with oral ciprofloxacin, obtain a culture, which could be important in case your target was actually MRSA or another pathogen.

Initial choices for uncomplicated nail puncture wounds of the foot: empiric antistaphylococcic antibiotics, empiric anti-pseudomonal oral antibiotics, superficial or deep (with lidocaine injection) culture, immediate exploration or incision and drainage of the puncture site? Do not forget the possible need for tetanus booster.

Few pediatricians are inclined to culture the infection that is not draining or fluctuant. Although Pseudomonas is the most likely pathogen, I have seen puncture wounds with S. aureus. A failed brief trial of inexpensive, less alarming antistaphylococcic antibiotics should not suppress Pseudomonas culture. Daily follow-up is essential in case the infection worsens or shows any signs of deteriorating into osteochondritis or tenosynovitis over the next few days.

Obviously, immediate incision and drainage or surgical exploration of the puncture site by an orthopedist is needed for signs of tendon or bone involvement, likely retained foreign body or worsening infection despite antibiotics. Anti-pseudomonal antibiotics are essential at this point.

Supervision, blind hogs, hot tubs and nails — is this a great country or what?

For more information:

• Long S, Pickering L, Prober C, eds. “Principles and Practice of Pediatric Infectious Disease.” 2nd ed. Philadelphia, Pa: Churchill Livingstone; 2003: 428.
• Feigin RD, Cherry J, Demmler G, Kaplan S, eds. “Textbook of Pediatric Infectious Diseases.” 5th ed. Philadelphia, Pa: W.B. Saunders; 2003:1558-1568.

• Stan L. Block, MD, has a pediatric practice in Bardstown, Ky., and is a member of the Infectious Diseases in Children Editorial Advisory Board.