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An 8-year-old boy with acute abdominal pain
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An 8-year-old boy was in the hospital for the management of acute abdominal pain when on hospital day four or five, he began complaining of pain in the skin overlying his hips.
The history of this illness began a few days before hospitalization with the onset of fever, abdominal pain and nonbloody diarrhea. He had been admitted to the surgery service when it was first thought that he had appendicitis. However, an abdominal CT scan revealed a normal-appearing appendix but did show a thickened cecum and distal ileum. Noteworthy lab tests at that time revealed a low white blood cell count of 4,700 with 47% granulocytes and 21% band forms. Urinalysis, metabolic profile and chest radiograph were normal. No cultures or stool studies were done at that time.
Pediatric Infectious Disease, Scott and White's Children's Health Center and Associate Professor of Pediatrics,
Texas A&M University, College of Medicine, Temple, Texas.
e-mail: jhbrien@aol.com
His fever and abdominal pain persisted along with worsening diarrhea, and sometimes he would awake with watery stool in his bed. On hospital day four, he was transferred to the medical service, at which time his stool and blood were sent for culture. Twenty hours later, his blood was reported to be growing a gram-negative rod, and treatment with gentamicin and ceftriaxone was begun. The organism was later identified as a non-typhi Salmonella species. His stool was reported positive for the same organism a couple of days later. During this interval is when he noticed the pain over his hips and brought it to our attention the next day.
Examination revealed an 8-year-old child curled up in the “fetal” position with normal vital signs with the only positive finding being the skin over both hips, which revealed numerous pustules overlying somewhat raised erythematous bases. They were mostly confined to the skin overlying the hips and so numerous in places to be confluent, especially over the left hip, as shown in Figures 1-4. Except for two or three other similar lesions distant to the hips, the rest of his skin exam was unremarkable.
By this time, he had defervesced, and the rest of his vital signs were also normal, but the pain from his skin was now his chief complaint.
Gram stains of two of the pustules (one from each hip area) revealed gram-negative rods, and cultures are pending.
What’s your diagnosis?
- Gram-negative folliculitis
- Bullous impetigo
- Pityriasis lichenoides et varioliformis acuta
- Contact dermatitis
Answer
The answer is A, gram-negative folliculitis. Both pustule cultures grew Escherichia coli. (I know you thought, as I did, that it was going to be Salmonella.) Presumably, this occurred as a result of the patient lying in stool on his sides (his preferred sleeping position) long enough to contaminate and occlude the follicles with stool that was teaming with E. coli.
The pathogenesis of folliculitis usually involves obstruction and/or microtrauma of the follicle, in the presence of a potential pathogen. Most cases will be due to Staphylococcus aureus, as seen in Figure 5 (a patient who shaved her legs and wore very tight jeans), but many other pathogens have been implicated. The term gram-negative folliculitis is mostly seen in the dermatology literature and specifically refers to folliculitis that occurs as a result of prolonged use of antibiotics for acne therapy. However, I think this case points out that given the right set of circumstances, unusual organisms such as E. coli may produce folliculitis. In this case, the E. coli was sensitive to the antibiotics that were being used for his Salmonella bacteremia, so all that was needed was to simply keep the skin clean and dry, and the problem was markedly improved on discharge.
Another form of gram-negative folliculitis is that caused by Pseudomonas aeruginosa from prolonged contact with the organism in hot tubs with water that has been inadequately treated. This generally requires no specific therapy beyond local skin care.
Bullous impetigo is a superficial S. aureus infection of the skin that results in vesicles or small blisters (Figure 6). The blistering is the result of a low–molecular-weight protein liberated by the organism (usually a phage group II S. aureus), usually referred to as epidermolytic toxin. This protein cleaves the intracellular bonds within the granular layer of the epidermis, resulting in vesicle or blister formation. For the same reason, if enough of this toxin got into the bloodstream, usually from a more significant infection, the patient would develop staphylococcus scalded skin syndrome.
The treatment of bullous impetigo is usually with an oral anti-S. aureus antibiotic. Nowadays, that usually means assuming methicillin-resistant S. aureus and treating with trimethoprim/sulfamethoxazole or clindamycin. In the child beyond 8 years of age, tetracycline may be used, pending culture and sensitivity results.
PLEVA is an acronym for Pityriasis Licheoides Et Varioliformis Acuta, also known as Mucha-Habermann disease. It is not an infectious disease at all but rather a form of childhood parapsoriasis seen in school-aged children. It is often confused with “persistent” varicella with macules and erythematous papules, but when one looks closely, there are no vesicles or pustules (Figure 7). The condition is self-limited and produces few symptoms, generally requiring only parental education. It may last up to a year. Referral to a dermatologist for phototherapy may be needed for those bothered by the condition.
Contact dermatitis is a fairly descriptive term that refers to a rash or lesion on the skin resulting from an irritant or allergen coming in direct contact with the skin.
Contact dermatitis virtually always has an inflammatory component to it and may have some blistering as well. This is shown in Figure 8: a young child with “pseudo” athlete’s foot, which is really a contact dermatitis, revealing erythema and broken blisters. The treatment, of course, is to remove the source and avoid further contact. Topical steroid cream will speed the recovery, and if secondarily infected, a seven- to 10-day course of oral antibiotics against S. aureus. However, “true” secondary infection is uncommon. Even though the rash may appear to be severely infected, if there is no pain (just itching) and no fever, it is likely to be just severely inflamed (Figure 9: a patient with poison ivy). Figure 10 is the same patient after a few days of systemic steroids and no antibiotics.
Comments
Summer is here. Remind your parents to protect their children from the sun and swimming pools. Also, skin infections like those mentioned above are more common this time of year. If a simple impetigo progresses to cellulitis, be sure it’s not caused by group A Streptococcus before treating with trimethoprim/sulfamethoxazole. It will likely progress on to a more serious level. Please keep in touch, and send me your ideas and comments.
In July we will have a correction on the specific type of juvenile idiopathic arthritis presented in the May issue.
What’s Your Diagnosis? is a monthly case study featured in Infectious Diseases in Children, with treatment information and discussion to follow.