necrobiosis lipoidica ( nl ) is a rare chronic granulomatous dermatitis first described in 1929 by oppenheim that usually appears in the lower extremities that affects about 0.31.2% of diabetic patients , the majority of whom have type 1 diabetes .
we report a case of a 16 y old girl who developed lesions on the lower extremities and in the interscapular area , which is an unusual location .
the patient , a caucasian 16-y - old girl , was born at term by non - consanguineous , healthy parents .
type 1 diabetes ( t1 dm ) had been diagnosed at one year of age .
our patient s medical history was otherwise unremarkable . until the age of 12 she maintained an adequate glucose control with hba1c < 34 mmol / mol .
thereafter her glucose control progressively worsened with a hba1c of 86 mmol / mol . at the age of 16 , during a routine diabetes follow - up visit , the patient presented with erythematous subcutaneous nodular lesions which had appeared 4 mo earlier , initially in the pretibial area and subsequently in the interscapular area .
her hba1c was 64 mmol / mol and daily insulin requirements were 0.95 u / kg / day . in the suspect of necrobiosis lipoidica , a skin biopsy was performed ( lower extremities and interscapular area ) ( figs . 1 and 2 )
the smaller lesions in the interscapular area showed signs of perivascular dermatitis which could be consistent with early stages of necrobiosis lipoidica ( fig .
it may initially be represented by erythematous circular papules which may gradually progress to yellowish - brown , telangectatic plaques with central atrophy and raised violaceous border .
the etiology of nl is still currently elusive and few data exist regarding the pediatric population .
however , due to the significant relationship with diabetes ( 7590% of patients with nl have or will develop t1 dm ) , many studies have proposed microangiopathy as leading etiological suspect . immune - complex vasculitis and collagen abnormalities may also represent potential underlying causes .
previous studies have shown that glucose control does not appear to be correlated with nl onset and severity . however , a study by cohen concluded on the contrary , that nl is usually associated with poor glucose control and that a tighter glucose control , as currently practiced , might improve or prevent this disorder .
diagnosis of nl is mainly clinical , but a bioptic evaluation may be useful especially in the early stages of disease .
differential diagnosis include erythema nodosum , lupus panniculitis , granuloma annulare , sarcoidosis and amyloidosis .
microscopic evaluation usually shows degeneration of collagen , granulomatous inflammation of subcutaneous tissues and of blood vessels , capillary basement membrane thickening and obliteration of vessel lumen .
other therapeutic options are antiplatelet agents , cyclosporine , thalidomide , clofazimine , anti - tnf agents , fumaric acid esters , puva , photodynamic therapy , hydroxychloroquine , and tacrolimus .
in patients with t1 dm , diagnosis of nl of the lower legs is usually unequivocal .
however , diagnosis may be more challenging in the presence of lesions with recent onset and/or atypical clinical presentation and unusual site . in these cases , nl must always be taken in consideration in order to avoid misdiagnosis , wrong / late treatment decisions and progression to ulceration .
written informed consent was obtained from the patient and parents for publication of this manuscript and any accompanying images .
a copy of the written consent is available for review by the editor - in - chief of this journal .
 introduction : necrobiosis lipoidica ( nl ) is a rare chronic granulomatous dermatitis that usually appears in the lower extremities . 
 it affects about 0.31.2% of diabetic patients , the majority of whom have type 1 diabetes . 
 the etiology and pathogenesis of this disorder are still unclear . 
 nl is characterized by skin rash that usually affects the shins . 
 the average onset is 30 years , with females being affected more commonly . 
 there are very few reported cases of necrobiosis lipoidica in children . 

 
 case report : we report a case of a 16 year old girl affected by type 1 diabetes mellitus ( 15 years disease duration ) who developed an erythematous nodular rash on the lower extremities and interscapular area . in the suspect of necrobiosis lipoidica , a skin biopsy was performed ( lower extremities and interscapular area ) . 
 the microscopic evaluation of the pretibial lesions was suggestive of necrobiosis lipoidica . 
 the smaller lesions in the interscapular area showed signs of perivascular dermatitis which could be consistent with early stages of necrobiosis lipoidica . local treatment with tacrolimus determined a progressive improvement of the lesions . 
 
 conclusion : in patients with t1 dm , diagnosis of nl of the lower legs is usually unequivocal . however , diagnosis may be more challenging in the presence of lesions with recent onset and/or atypical clinical presentation and unusual site . in these cases , 
 nl must always be taken in consideration in order to avoid misdiagnosis , wrong / late treatment decisions and progression to ulceration . 