Mysterious Foot Lesions in a Healthy Eight Year Old

An 8-year-old Hispanic male patient with no significant medical history was referred to Children's Hospital & Research Center Oakland for evaluation of left foot pain, swelling, and redness. Two days before admission, the child noticed that his left foot was swollen. The next morning, he awoke with pain in the left foot; and was evaluated at his pediatrician's office. Laboratory studies including a complete blood count and comprehensive metabolic panel were normal. A blood culture was also obtained. The following morning, the patient had worsening erythema, edema, and pain on the plantar surface of his left foot and was unable to bear weight. His pediatrician referred him to the Emergency Department for further evaluation. There was no reported trauma or puncture wound to the foot, and the patient had no previous similar episodes. He was otherwise well and denied any joint pain, swelling, or rashes elsewhere. In addition, he denied any fevers, respiratory symptoms, vomiting, or diarrhea. There was no family history of any rheumatologic or dermatologic conditions, and no sick contacts. The patient and his family resided in Hayward, CA and reported no travel except to Modesto, CA on occasion to visit an uncle. There were no animal exposures or known insect bites. On physical examination, the patient was afebrile with normal vital signs. His physical examination was remarkable for numerous exquisitely tender, nodular lesions, each measuring about 5 to 10 mm in diameter, on the plantar surface of his left foot, mostly on the ball and arch with sparing of the heel (Fig., Supplemental Digital Content 1, https://links.lww.com/INF/A776). The lesions were erythematous with a purplish hue and blanched with pressure. Some were coalescent; others were target-like in appearance. The foot itself was warm and swollen, and the patient was unable to bear weight secondary to pain. The rest of the body was spared, including the dorsal surface of the left foot, his entire right foot, and both of his legs. He had no lymphadenopathy. Initial evaluation included a WBC of 12,100/mm3 with 51% segmented neutrophils, 12% bands, 23% lymphocytes, 11% monocytes, 1% eosinophils, and 2% reactive lymphocytes; hemoglobin of 12.5 g/dL; platelet count of 268,000/mm3; C-reactive protein of 8.3 mg/dL; and erythrocyte sedimentation rate of 30 mm/h. A radiograph of his left foot showed soft-tissue swelling but no fracture or foreign body. A second blood culture was obtained. The patient was treated with intravenous cefazolin for presumed cellulitis. Soon after admission, he became febrile to 39.1°C, but defervesced after receiving a dose of acetaminophen and subsequently had no further fevers. Because there was concern for a vasculitis or other rheumatological disorder, further laboratory studies were obtained, including a urinalysis that was negative for protein and blood; a comprehensive metabolic panel that was normal; and antinuclear antibody, antidouble stranded DNA, complement levels, antistreptolysin O titers, rheumatoid factor, and perinuclear and circulating antineutrophil cytoplasmic antibodies that were all normal. All of his blood cultures were negative. Additional history was obtained and a diagnostic procedure was performed. Denouement Fluid aspirated from one of the plantar nodules grew Pseudomonas aeruginosa, and the diagnosis of Pseudomonas hot-foot syndrome was made. Further history obtained from the family revealed that 2 days before the onset of symptoms, the patient was playing barefoot in a plastic wading pool at his uncle's house in Modesto, CA. The pool had not been cleaned or disinfected recently and reportedly had been full of dirty water containing grass, leaves, and dirt. The patient clinically improved with resolution of pain by hospital day 4 without antipseudomonal treatment. Despite the diagnosis, the medical team continued cefazolin throughout the hospitalization, and the patient was discharged on cephalexin to complete a 10-day course of therapy. Pseudomonas hot-foot syndrome was described in 2001 by Fiorillo et al1 after a community outbreak in Canada of exquisitely painful erythematous plantar nodules in 40 children after exposure to a wading pool with water containing a high concentration of P. aeruginosa. All these children, ages 2 to 15 years old, reported intense pain on the soles of their feet within 10 to 40 hours after using the wading pool. Within hours of onset, marked swelling, redness, and warmth developed, accompanied by such exquisite pain that weight bearing and for some, even wearing socks or shoes became intolerable. On physical examination, all of these children had diffuse, dusky erythema of the soles, with deep, exquisitely tender, violaceous 1- to 2-cm nodules on the weight-bearing surfaces of their feet. In addition to the painful plantar nodules, 1 child also had a tender nodule on a finger, 1 had palmar erythema, and another had buttock folliculitis. Laboratory results were significant for elevated inflammatory markers (ESR and CRP) and mild leukocytosis. P. aeruginosa was cultured from a deep pustule of one of the patients and from water taken from the wading pool 11 days after the first case was identified. These isolates were found to be identical by pulsed-field gel electrophoresis. Two patients underwent punch biopsies of their plantar nodules. One biopsy revealed neutrophilic invasion of the perivascular, interstitial, and periadnexal spaces extending to the lobules of subcutaneous fat along with extravasated red blood cells in the dermis. The other biopsy showed neutrophilic infiltrate around the wall and lumen of the eccrine sweat glands, a deep dermal abscess extending to the adipose tissue, and a focal area of vasculitis with a blood vessel thrombus. All the children completely recovered in 1 to 14 days with supportive care such as cold compresses, analgesic agents, and foot elevation. None received antipseudomonal therapy, though 3 patients were treated with cephalexin. Three patients had recurrence of plantar nodules but only after using the same pool at a later date. It was suspected that Pseudomonas hot-foot syndrome had resulted from entry of the bacteria through miniscule breaks in the skin caused by the abrasive grit at the bottom of the pool. P. aeruginosa has been known to cause several distinct infections of the skin, including a greenish discoloration of the nail known as green nail syndrome, white scaling and maceration of the skin between the toes known as toe web intertrigo, and malignant otitis externa.2P. aeruginosa can also cause burn and surgical wound infections3 as well as superinfection of acne vulgaris.2 In patients with pseudomonas sepsis, characteristic skin ulcers with ecchymotic and necrotic centers and bright red areolae can develop called ecthyma gangrenosum.4 In addition, P. aeruginosa has been identified as the cause of “hot tub folliculitis,” or folliculitis associated with the usage of swimming pools, hot tubs, whirlpools, saunas, and hydrotherapy pools. These patients develop pruritic follicular, maculopapular, vesicular, or pustular lesions after being exposed to contaminated water, sometimes in association with otitis externa, malaise, fatigue, low-grade fever, and mastitis.2–6 Lesions can occur on any hair-bearing skin on the body, but are more commonly found on the buttocks, hips, axillae, and trunk, which are regions containing apocrine sweat glands that often open into hair follicles.3 In addition, the greater exposure to moisture and friction in these areas may facilitate entry of the organisms into the hair follicles. Painful plantar nodular lesions in these cases are rare but have been documented as occurring either preceding or concurrent with the folliculitis.3,5 In 2007, Yu et al7 described an outbreak of pseudomonas skin infections in 33 children within 6 to 48 hours of using of a hot tub at a pool party. In this outbreak, several children developed erythematous pustular lesions on the face and trunk characteristic of pseudomonas hot-tub folliculitis, while others developed markedly tender, erythematous nodules on the palms and/or soles. Some children presented with both types of skin lesions. Many of the children developed low-grade fever, but only 2 were hospitalized. Both these hospitalized children had leukocytosis. No skin biopsies were performed, but isolates of P. aeruginosa cultured from the pustules of one of the patients and from the hot tub water showed nearly identical repetitive sequence polymerase chain reaction banding patterns. These patients were diagnosed with pseudomonas folliculitis with “hot hand-foot syndrome.” Although hot tub folliculitis and Pseudomonas hot hand-foot syndrome can occur simultaneously, they seem to be distinct entities. With both entities, certain factors such as hot water, high pH, and low chlorine concentrations increase risk of Pseudomonas infection. However, the sites of entry for hot tub folliculitis are the hair follicles, thus usually sparing the palms and soles,3 whereas in Pseudomonas hot-foot syndrome, plantar lesions are thought to result from inoculation of P. aeruginosa into the soles due to repeated trauma caused by rubbing the soles against the abrasive surfaces of the pool.1 This could explain why children, teenagers, and young adults seem more likely to develop palmar and plantar nodules: children have a thinner epidermis on their palms and soles than adults, and in addition, these age groups tend to be more active and may therefore sustain more friction injury on their hands and feet.1,7 Pseudomonas hot-foot syndrome is a self-limited disease with most patients recovering without antipseudomonal therapy. Outbreaks can be prevented by keeping pools and hot tubs well-maintained and adequately chlorinated to suppress the concentrations of P. aeruginosa in the water. The Centers for Disease Control and Prevention now recommends that the concentration of free chlorine in public swimming pools be kept at 1 to 3 parts per million and the pH level be maintained between 7.2 to 7.8.8 When this infection does occur, a detailed exposure history and recognition of the characteristic lesions can help to prevent unnecessary hospitalization and antibiotic treatment.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.