46 Clinical Rounds SKIN & ALLERGY NEWS • October 2005 How to Diagnose Puzzling Pediatric Skin Problems BY HEIDI SPLETE Senior Writer Pilomatricoma A 15-month-old girl presented with a bump on her cheek—a firm, bluish, cystic papule that moved back and forth under pressure. When one end of the lesion was palpated, the other end would pop up, a phenomenon also known as a “teetertotter sign.” Annular Urticaria A 3-year-old girl presented with red, swollen, annular plaques on her skin, and had swollen hands and feet. She had been otherwise healthy and was taking no medications. The condition arose suddenly; the parents noticed the rings and swelling one morning when picking up the child from her bed. On closer inspection, the rings were red and blanchable, with clear white Wheezing in Infants Worsens Near Stop-and-Go Traffic B Y M I C H E L E G. S U L L I VA N Mid-Atlantic Bureau I nfants who live near roads with lots of stop-and-go bus and truck traffic are significantly more likely to develop wheezing than those who live near steady traffic or those who aren’t exposed to much traffic, Patrick Ryan and his associates reported. The association may be related to increased amounts of diesel exhaust particles (DEP) shed when the vehicles accelerate from a stop, said Mr. Ryan, of the University of Cincinnati, and his colleagues. Other studies have shown that acceleration from stop increases this particulate matter. “Sampling for fine particulate matter and black carbon inside a bus and a car traveling ahead of the bus showed that the average DEP levels were approximately 20 mcg/m3 and 5 mcg /m3, but during stop-and-go traffic the levels increased to more than 30 mcg /m3 and 20 mcg/m3, respectively,” they said. The researchers examined wheezing without cold over 1 year in 622 infants (median age 7.5 months). The infants were part of the Cincinnati Childhood Allergy and Air Pollution Study; all had at least one atopic parent, the researchers said ( J. All. Clin. Immunol. 2005;116:279-84). Living within 100 meters of stop-and-go traffic was associated with a 2.5-fold increased risk of wheezing and was the most important risk factor. Most (374) of the infants were unexposed to traffic; 176 lived near moving bus and truck traffic, and 99 lived near stop-and-go traffic. Infants exposed to stopand-go traffic were more likely to be black, have out-of-home care, and have a father with asthma, and they were less likely to have been breast-fed. The researchers adjusted for these variables in the analysis. Of the 622 infants, 8% (50) reported wheezing without a cold. The prevalence of wheezing in the unexposed infants was 5.8%. The prevalence was 7.4% in infants exposed to moving traffic, and 17.2% in infants exposed to stop-and-go traffic. The prevalence of wheezing was three times higher (19%) in infants who lived less than 50 meters from moving traffic compared with the unexposed group, the investigators said. The prevalence of wheezing in those who lived 200-300 meters from moving traffic was 12%—more than double that of infants who were unexposed. Living within 100 meters of stop-and-go traffic was associated with a 2.5-fold increased risk of wheezing and was the most important risk factor for wheezing. However, the authors noted, “Because wheezing in the first year of life is generally a poor predictor of later development of childhood asthma, results must be interpreted cautiously.” ■ P HILADELPHIA OF centers. Some were imperfect circles. The diagnosis is annular urticaria. “These types of cases are frequently referred for suspected erythema multiforme,” Dr. Yan noted. “Lesions of annular urticaria are evanescent; the lesions fade and move, and the lesions can form imperfect circles with clear centers,” he explained. The lesions may disappear within 24 hours, only to show up elsewhere, he said. By contrast, erythema multi- Annular urticaria, which is often mistaken for erythema forme appears as multiforme, can be distinguished by its evanescence. fixed target, or “bull’s-eye,” lesions with dusky centers erythema multiforme requires a detailed and is associated with mucous membrane history to determine underlying causes, removal or treatment of those causes, and ulcers. The two conditions are treated quite dif- consideration of steroid therapy if indiferently, Dr. Yan emphasized. Annular ur- cated. Dr. Yan often refers to annular urticaria responds to combinations of anti- ticaria as “urticaria multiforme” because histamines or occasionally steroids; these cases are so regularly mistaken. ■ C HILDREN ' S H OSPITAL Although these lesions may resemble dermoid cysts or epidermal inclusion cysts, the diagnosis in this case was pilomatricoma, distinguished by its bluish color and the presence of the teeter-totter sign. The lesions most often occur on the head or neck, although other areas occasionally are affected. Pilomatricomas generally are solitary, benign, frequently calcified, and arise from hair follicles. In some cases, the lesions resolve spontaneously, but more often, they persist and grow, and surgical intervention is recommended. Pilomatricomas may rupture, which can cause inflammation and scarring. Although pilomatricomas generally are isolated findings, they may be associated with systemic disorders such as Gardner’s syndrome, myotonic dystrophy, and sarcoidosis. Pilomatricomas may be associated with systemic disorders such as Gardner’s syndrome or sarcoidosis. COURTESY The Hair Collar Sign A boy is born with an area of localized, circular alopecia covered by a glossy membrane. The area is surrounded by a collection of dark, terminal hairs. Palpation reveals that a lump is present. Occasionally mistaken for fetal scalp monitor trauma, neonatal herpes simplex infection, or a nevus sebaceus of Jadassohn, this characteristic pattern—a collar of coarse hair surrounding an area of membranous aplasia cutis congenita—can be a marker for cranial dysraphism, a developmental defect of the skull potentially associated with structural neurologic defects. The scalp defect may represent only the tip of the iceberg, Dr. Yan noted, since underlying bony defects or ectopic brain tissue may be present. In such cases, magnetic resonance imaging is essential to rule out underlying abnormalities, including atretic encephalocele or heterotopic brain tissue. A collar of hair around membranous aplasia cutis congenita can indicate the presence of cranial dysraphism. P HOTOS O R L A N D O — Pediatric skin conditions often pose diagnostic challenges because many cutaneous disorders have similar clinical features. Annular lesions of granuloma annulare may be mistaken for tinea corporis; follicular papules of keratosis pilaris may be confused with follicular eczema; and nail psoriasis may be misdiagnosed as onychomycosis. At a meeting sponsored by the American Academy of Pediatrics, Albert C. Yan, M.D., director of pediatric dermatology at the Children’s Hospital of Philadelphia, provided some helpful diagnostic tips for distinguishing some of these potentially puzzling dermatologic problems.