PEDIATRIC DERMATOLOGY

PEDIATRIC DERMATOLOGY

What's your DX?

By Bernard A. Cohen, MD

A 12-year-old girl with insulin-dependent diabetes comes toyour office for you to evaluate several scar-like reddish-yellowplaques that developed on her shins over the last three months.The lesions do not hurt or itch, she reports, but they are continuingto spread.

She was diagnosed with diabetes when she was in first grade,and her blood sugar has been kept under very tight control sincethen. Her growth and development have been normal, and she isan "A" student.

Her examination is significant only because of three or fourlarge (3­6 cm) plaques on each shin. The plaques are nontender,indurated, elongated ovals. Her upper anterior thighs show minimalerythema surrounding several insulin injection sites.

1. What would you consider in the differential diagnosis?

2. What is the relationship between her skin lesions and diabetes?

3. How would you treat her skin?

Discussion

The changes on this child's shins are typical of necrobiosislipoidica diabeticorum (NLD). NLD is a degenerative disorder ofdermal collagen characterized by reddish-yellow, indurated plaqueson the anterior legs.^1­3 Lesions usually beginas small red-to-violaceous papules. Their diameter increases from1 cm to 4 cm or larger over months or years. As plaques expand,the center becomes shiny, yellow, and atrophic. Telangiectasiasextend from the center to the violaceous border. The shins aremost commonly affected, although NLD occasionally involves thethighs, head and neck, or arms.

NLD and diabetes. Although NLD is rare in diabetics, at leasthalf of affected individuals have insulin-dependent diabetes.¹About 75% of patients with necrobiosis are female. Although theincidence peaks in young adulthood and middle age, NLD has beenreported in all age groups, including early childhood. In somecases, necrobiosis precedes the onset of clinical diabetes byyears. About half of nondiabetic patients demonstrate chemicaldiabetes, and many have a strong family history of diabetes.

Although the cause is unknown, investigators suggest that somesort of vascular insult, triggered by diabetes, initiates thenecrobiotic changes in collagen.^2,3 However, controlof hyperglycemia does not correlate with the development or progressionof NLD.

Histologically, one observes granulomatous inflammation aroundaltered, degenerating collagen, which extends in large bands deepinto the reticular dermis.⁴ The overlying epidermisis atrophic and may be ulcerated. Thickening of vascular walls,proliferation of endothelial cells, and occasionally vascularocclusion are seen throughout the dermis. The yellow color comesfrom lipid deposits within necrobiotic collagen.

Differential diagnosis. NLD can usually be differentiated fromgranuloma annulare, which is not associated with epidermal atrophyor ulceration. Moreover, granuloma annulare in children is notassociated with diabetes. In some patients fibrotic or atrophicplaques in scleroderma or lichen sclerosis et atrophicus mimicNLD. The clinical course and skin biopsy findings, however, aredistinctive. One third of juvenile diabetics develop diffuse nonpittingwaxy edema of the hands during the first two decades of life.The lack of distinctive cutaneous lesions, atrophy, or color changeshelps differentiate this condition from NLD. The histology ofwaxy edema shows increased dermal collagen, thought to be causedby increased glycosylation of the proteins in the collagen matrixand by the proliferation of dermal fibroblasts.

Treatment. NLD is usually asymptomatic, and plaques may remainstable or occasionally heal without treatment. However, most lesionspersist or progress slowly. In about one third of patients, minortrauma of the atrophic surface leads to chronic, painful ulcerations.^1­3NLD may respond to topical steroids or to intralesional steroidsinjected into the expanding red border. Other treatments thathave been reported include dipyridamole and aspirin, pentoxifylline,systemic corticosteroids, and topical retinoids.^2,3,5,6Ulcerated NLD may respond to conservative therapy including wet-to-wetcompresses, bio-occlusive dressings, and gentle debridement. Chroniculcers may require surgical intervention with excision and grafting.All patients should be counseled to protect involved sites fromtrauma, and nondiabetics should be screened for chemical diabetes.

The plaques on the shins of the 12-year-old girl in this caseimproved minimally with application of topical steroids and nonew lesions have appeared.

REFERENCES

1. Muller SA, Winkelmann RK: Necrobiosis lipoidica diabeticorum:A clinical and pathological investigation of 171 cases. Arch Dermatol1966;93:272

2. Lowitt MH, Dover JJ: Necrobiosis lipoidica (Review). J AmAcad Dermatol 1991;25(5pt1):735

3. Boulton AJ, Cutfield RG, Abouganeu D, et al: Necrobiosislipoidica diabeticorum: A clinicopathologic study. J Am Acad Dermatol1988;18:530

4. Muller SA, Winkelmann RK: Necrobiosis lipoidica diabeticorum:Histologic study of 98 cases. Arch Dermatol 1966;64:1

5. Petzelbauer P, Wolff K, Tappeiner G: Necrobiosis lipoidica:Treatment with systemic corticosteroids. Br J Dermatol 1992;126:542

6. Heymann WR: Necrobiosis lipoidica treated with topical tretinoin.Cutis 1966;58;53

THE AUTHOR is Director, Pediatric Dermatology and CutaneousLaser Center, and Associate Professor of Pediatrics and Dermatologyat Johns Hopkins University School of Medicine, Baltimore.
He is a Contributing Editor for Contemporary Pediatrics.