En coup de sabre (ECDS) is a rare subtype of linear scleroderma that is limited to the hemiface in a unilateral distribution. The lesional skin first exhibits contraction and stiffness that lead to characteristic fibrotic plaques with associated linear alopecia.1 The pansclerotic plaques are ivory in color with hyperpigmented to violaceous borders extending as a paramedian band on the frontoparietal scalp.2,3 The skin lesions bear resemblance to the stroke of the sabre sword, giving the condition its unique name. Many patients initially present with concerns of frontal scalp alopecia.3 Linear morphea, including the ECDS subtype, is predominantly seen in children and women, usually presenting within the first 2 decades of life.1,4
The differential diagnoses of ECDS include focal dermal hypoplasia, steroid atrophy, localized morphea, and lupus profundus.5 En coup de sabre should be distinguished from progressive hemifacial atrophy (PHA)(also known as Parry-Romberg syndrome).6 Progressive hemifacial atrophy presents as unilateral atrophy of the face involving skin, subcutaneous tissue, muscle, and underlying bone in the distribution of the trigeminal nerve.1 Both PHA and ECDS exist on a spectrum of linear scleroderma and may coexist in the same patient.6
There is a strong association with extracutaneous neurologic involvement, including seizures, ocular abnormalities, trigeminal neuralgia, and headache.7-10 One study examining ECDS and PHA demonstrated that 44% (19/43) of patients who underwent central nervous system imaging had abnormal findings.11 The majority of patients had magnetic resonance imaging with or without contrast, computed tomography, or both. The most common findings on T2-weighted images were white matter hyperintensities, mostly in subcortical and periventricular regions. The findings were bilateral in 61% (11/18) of patients and ipsilateral to the lesion in 33% (6/18) of patients.11 We present a case of ECDS masquerading as alopecia in a 77-year-old woman.
A 77-year-old white woman presented with a chief concern of hair loss on the scalp that had been present since 12 years of age. During her adult life, the scalp lesion remained unchanged with no associated symptoms. Her medical history was remarkable for hypertension and non–insulin-dependent diabetes mellitus. The patient denied any history of seizure disorders, facial paralysis, or neurologic deficits. Physical examination revealed a 13.6-cm linear, alopecic, hyperpigmented plaque extending from the left forehead and temporal scalp to the posterior occipital scalp with notable loss of underlying subcutaneous tissue (Figure). The left temporal scalp and forehead demonstrated pronounced atrophy with overlying telangiectases. Minimal depression was observed in the temporal scalp and forehead. The left cranial bone was easily palpable with no underlying subcutaneous tissue present. Computed tomography of the brain revealed no underlying skull or soft tissue abnormalities. No treatment was initiated, as the lesion was of minimal concern to the patient.