Over the last decade, the incidence of tuberculosis (TB) in the pediatric population has increased worldwide. In 1993, 1721 children in the United States developed tuberculosis, a 40% increase from 1987.1 The World Health Organization estimates that 4.5 million tuberculosis-related deaths will occur among children in the 1990s.2,,3 With the increasing incidence of tuberculosis, an accompanying rise in the incidence of tuberculids and other skin manifestations of this disease may occur.
Erythema induratum of Bazin (EIB) is a tuberculid characterized by chronic or recurrent tender subcutaneous nodules which sometime ulcerate. The lesions typically are located on the lower extremities of adult women.4 Histologically, a lobular granulomatous panniculitis with extensive vasculitis is seen.5Clinicopathologic correlation is required for the diagnosis, because no single finding is pathognomonic. After 50 years of controversy over its relationship to tuberculosis, EIB now is generally accepted to be a true tuberculid and histologically classified as a subset of nodular vasculitis.5 To the best of our knowledge, the youngest patient with EIB reported previously in the English language literature was a 13-year-old Korean girl described briefly in a series.6 We describe herein the youngest patient with EIB: a 22-month-old boy with EIB secondary to pulmonary tuberculosis. This report emphasizes that recognition, investigation, and treatment of tuberculids is essential in the pediatric age group.
A 22-month-old, previously healthy Asian boy developed a transient fever (103°F) and an asymptomatic papular pink eruption resembling insect bites over the face, back, and legs. The eruption persisted for 3 weeks, followed by development of tender nodules on the lower legs. Results of a tuberculin skin test were positive at that time, with 22 × 25 mm induration. Ten months before, a tuberculin skin test result had been negative. The patient was born in New York City and had no history of bacilli Calmette-Guérin vaccination or travel outside of New York. His parents had immigrated from China 13 years earlier, and had no evidence of active tuberculosis. His babysitter traveled frequently between China and the United States and was the suspected source case, but she relocated to China and was lost to follow-up.
On admission to Bellevue Hospital, the patient was afebrile and without cough or systemic symptoms. Results of physical examination were normal, except for the skin. There were scattered 3- to 6-mm erythematous to violaceous papulonodules on the face and extremities. There were three indurated erythematous to violaceous nodules on the anterior and posterior lower legs. They ranged in diameter from 3 to 7 cm and were extremely tender (Fig 1). No ulceration was present.
A right middle lobe infiltrate without cavitation was noted on chest radiography (Fig 2) and confirmed with computed tomography. The computed tomography scan revealed hilar adenopathy that was not evident on radiography. Multiple gastric aspirates were negative for acid-fast bacilli. Skin biopsy from a nodule on the calf demonstrated a granulomatous lobular panniculitis with extension into the septae. Areas of fat necrosis without caseation and vasculitis with destruction of large and small vessels were present (Fig 3). Special stains and tissue culture for acid-fast bacilli and other organisms were negative. Polymerase chain reaction for detecting Mycobacterium tuberculosis DNA on formalin-fixed, paraffin-embedded tissue was negative.
The patient was treated with isoniazid, rifampin, pyrazinamide, and ethambutol for 2 months. The nodules worsened and diminished for 1 month and then resolved without sequelae. The patient underwent an additional 4 months of isoniazid and rifampin treatment under directly observed therapy and is clinically well with resolution of the pulmonary infiltrate.
Cutaneous TB may be divided into four categories.7The first includes cutaneous manifestations resulting from exogenous infection (eg, TB verrocosa cutis and primary inoculation TB). The second stems from endogenous spread of tuberculosis (eg, lupus vulgaris, scrofuloderma, metastatic TB abscess, and acute miliary TB). Cutaneous reactions attributable to bacilli Calmette-Guérin vaccination make up the third category. Finally, a group of cutaneous eruptions known as the tuberculids, arise from hypersensitivity reactions to internal TB infection or disease. The three tuberculids are EIB, papulonecrotic tuberculid (PNT), and lichen scrofulosorum. Although all tuberculids are uncommon in the pediatric age group, PNT probably is the most common,8 and EIB the least common.
Tuberculids most likely result from a hypersensitivity reaction to antigenic fragments of dead bacilli that have been deposited hematogenously in the skin. Recent studies have demonstrated M tuberculosis DNA in skin lesions by polymerase chain reaction in 25% to 75% of specimens tested.9–11 Patients have a moderate to high degree of immunity against tubercle bacilli. PPD reactions typically are strong, with blistering or necrotic reactions occasionally seen. Tubercle bacilli usually are not evident by special stains of skin lesions or by tissue cultures from skin biopsies.5 Tuberculids respond well to appropriate antituberculous therapy.
It has been postulated that two of the tuberculids, PNT and EIB, may represent the same disease process, varying only by the caliber of blood vessels affected, with PNT affecting the more superficial vessels and EIB the deeper, larger vessels. This is supported by reports of their simultaneous co-existence in at least 10 patients12–15 and their histopathologic similarities.5
In this patient, the initial differential diagnosis included erythema nodosum, which has a strong predilection for the anterior aspect of the lower legs, usually does not ulcerate, and generally has a transient course, involuting within a few weeks. In contrast, EIB usually occurs on the posterior aspects of the lower legs, frequently ulcerates, and commonly exhibits a chronic or remitting course.5 Histopathologically, erythema nodosum shows a septal panniculitis, without fat necrosis, and mild or absent vasculitis. In EIB, however, a severe vasculitis is common, with resultant fat necrosis and granulomatous lobular panniculitis, as occurred in this patient.
The tuberculids are especially likely to go unrecognized or misdiagnosed in children because they are uncommon and because no pathognomonic clinical or laboratory finding exists. Furthermore, diagnosis of TB infection or disease in children requires a particularly high index of suspicion. Clinical symptoms of TB often are less obvious, and laboratory tests have lower sensitivity and specificity in children than in adults.16 For example, gastric aspirates and sputum cultures for M tuberculosis are positive in <50% of young children with active pulmonary TB.16 In addition, chest radiography often is misinterpreted when TB is not consciously considered.
This report illustrates that EIB can be the presenting sign of TB infection or disease, even in the very young child. Although tuberculids are rare in children, we believe they may be underrecognized. Tuberculids may become more common, in consideration of the resurgence of tuberculosis worldwide. A high index of suspicion, along with clinical, laboratory, and histopathologic correlation, is necessary to make the correct diagnosis. Thorough investigation for TB is indicated whenever a tuberculid is suspected.
- TB =
- tuberculosis •
- EIB =
- erythema induratum of Bazin •
- PNT =
- papulonecrotic tuberculid
- Dolin PJ,
- Raviglione MC,
- Kochi A
- ↵McNutt NS, Moreno A, Contreras F. Inflammatory disease of the subcutaneous fat. In: Elder D, Elenitsas R, Jaworsky C, Johnson BJ, eds. Lever's Histopathology of the Skin. 8th ed. Philadelphia, PA: Lippincott-Raven; 1997;429–440
- ↵Tappeiner G, Wolff K. Tuberculosis and other mycobacterial infections. In: Fitzpatrick TB, Eisen AZ, Wolff K, Freedberg IM, Austen KF, eds. Dermatology in General Medicine. 4th ed. New York, NY: McGraw-Hill; 1993;2370–2373
- Schneider JW,
- Jordaan HF,
- Geiger DH,
- Victor T,
- Van Helden PD,
- Rossouw DJ
- Copyright © 1999 American Academy of Pediatrics