Pediatric Leg Ulcers: Going Out on a Limb for the Diagnosis

Compared to the adult population with a prevalence of lower extremity ulcers reaching approximately 1% to 2%, pediatric leg ulcers are much less common and require dermatologists to think outside the box for differential diagnoses.¹ Although the most common types of lower extremity ulcers in the adult population include venous leg ulcers, arterial ulcers, and diabetic foot ulcers, the etiology for pediatric ulcers is vastly different, and thus these statistics cannot be extrapolated to this younger group. Additionally, scant research has been conducted to construct a systemic algorithm for helping these patients. In 1998, Dangoisse and Song² concluded that juvenile leg ulcers secondary to causes other than trauma are uncommon, with the infectious origin fairly frequent; however, they stated further workup should be pursued to investigate for underlying vascular, metabolic, hematologic, and immunologic disorders. They also added that an infectious etiology must be ruled out with foremost priority, and a subsequent biopsy could assist in the ultimate diagnosis.²

To further investigate pediatric leg ulcers and their unique causes, a PubMed search of articles indexed for MEDLINE published from 1995 to present was performed using the term pediatric leg ulcers. The search yielded approximately 100 relevant articles. The search generated more than 47 different causes of leg ulcers and produced unusual etiologies such as trophic ulcers of Lesch-Nyhan syndrome, ulcers secondary to disabling pansclerotic morphea of childhood, dracunculiasis, and dengue hemorrhagic fever, among others.^3-6 The articles were further divided into 4 categories to better characterize the causes—hematologic, infectious, genodermatoses, and autoimmune—which are reviewed here.

Hematologic Causes

Hematologic causes predominated in this juvenile arena, with sickle cell disease specifically comprising the vast majority of causes of pediatric leg ulcers.^7,8 Sickle cell disease is a chronic disease with anemia and sickling crises contributing to a myriad of health problems. In a 13-year study following 44 patients with sickle cell disease, Silva et al⁸ found that leg ulcers affected approximately 5% of pediatric patients; however, the authors noted that this statistic may underestimate the accurate prevalence, as the ulcers typically affect older children and their study population was a younger distribution. The lesions manifest as painful, well-demarcated ulcers with surrounding hyperpigmentation mimicking venous ulcers.⁹ The ulcers may be readily diagnosed if the history is known, and it is critical to maximize care of these lesions, as they may heal at least 10 times slower than venous leg ulcers and frequently recur, with the vast majority recurring in less than 1 year. Furthermore, the presence of leg ulcers in sickle cell disease may be associated with increased hemolysis and pulmonary hypertension, demonstrating the severity of disease in these patients.¹⁰ Local wound care is the mainstay of therapy including compression, leg elevation, and adjuvant wound dressings. Systemic therapies such as hydroxyurea, zinc supplementation, pentoxifylline, and transfusion therapy may be pursued in refractory cases, though an ideal systemic regimen is still under exploration.^9,10 Other major hematologic abnormalities leading to leg ulcers included additional causes of anemia, such as thalassemia and hereditary spherocytosis. These patients additionally were treated with local wound care to maximize healing.^11,12

Infectious Causes

Infectious causes of pediatric ulcers were much more varied with a myriad of etiologies such as ulcers from ecthyma gangrenosum caused by Pseudomonas aeruginosa to leishmaniasis and tularemia. The most commonly reported infection causing leg ulcers in the pediatric literature was Mycobacterium ulcerans, which led to the characteristic Buruli ulcer; however, this infection is likely grossly overrepresented, as more common etiologies are underreported; the geographic location for a Buruli ulcer also is important, as cases are rare in the United States.^13,14 A Buruli ulcer presents as a well-defined, painless, chronic skin ulceration and most commonly affects children.¹⁵ Exposure to stagnant water in tropical climates is thought to play a role in the pathogenesis of this slow-growing, acid-fast bacillus. The bacteria produces a potent cytotoxin called mycolactone, which then induces tissue necrosis and ulceration, leading to the clinical manifestations of disease.¹⁵ The ulcers may heal spontaneously; however, up to 15% can be associated with osteomyelitis; treatment includes surgical excision and prolonged antibiotics.¹⁴ Given the numerous additional causes of pediatric leg ulcers harboring infections, it is critical to be cognizant of the travel history and immune status of the patient. The infectious cause of leg ulcers likely predominates, making a biopsy with culture necessary in any nonhealing wound in this population prior to pursuing further workup.