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Incidence

Many authors postulate that LScs and PRS are clinical variants of the same disease. We will discuss both entities together in this condition. Linear Scleroderma (LS) incidence ranges from 0.4 to 2.7 per 100,000 people. Genetics participation in pathogenesis appears to be relatively weak, since only a 4.7% concordance between twins has been observed and family studies revealed only 1.6% frequency among first-degree relatives. Although present in all races, the prevalence among Caucasians is increased, summing up 72 to 82% of the patients. Females are primarily affected, and a similar distribution between children and adults occurs. Disease incidence peaks in the fifth decade of life in adults, whereas 90% of children are diagnosed between 2 and 14 years of age.

Clinical Characteristics

Linear scleroderma en coup de sabre (LSsc) is a rare subset of Linear Scleroderma (LS). LS has been associated to systemic symptoms. Rheumatologic, ophthalmologic, and neurologic manifestations seem to be present in around 20% of the patients, and, in those with LScs, nervous system disorders are the most prevalent extracutaneous presentation. The typical presentation affects frontoparietal region, and the mean age of onset is around 13 years old. Available data suggests a complex pathogenesis of scleroderma, in which blood vessels, the immune system, and extracellular matrix are affected and may contribute to the development of the disease. LScs presents in a band-like fashion on the frontoparietal scalp and forehead. Alopecia is common and many times is the patient\\\'s main concern. Skin lesions may extend to the nose, cheek, chin, and neck and usually have an active stage lasting 2 to 5 years. Muscle, cartilage, and bone lesions incur in facial atrophy: in this scenario, Parry-Romberg syndrome (PRS) must be considered a differential diagnosis. Up to 28% of patients having LScs manifests PRS features, such as a unilateral slowly progressive atrophy of the face. PRS commonly affects dermatomes of trigeminal nerve. Skin, soft tissue muscles, and underlying bone structures are involved. Skin hyperpigmentation and discoloration and hairless patches can be present. Many authors postulate that LScs and PRS are clinical variants of the same disease. Arguments for PRS inclusion on the spectrum of LS disorders are compelling. LScs and PRS coexist in 20 to 37% of the patients with LScs diagnosis, and both conditions have similar age of onset and disease course. Furthermore, dermatologic findings in PRS are sometimes indistinguishable from those of LS. However, some authors still consider them as different entities, since PRS does not always have skin thickening and the hemifacial atrophy occurring in PRS is usually more prominent. LScs has been associated with a variety of neurologic abnormalities and typically is preceded by the development of cutaneous disease by months to years. Nervous system involvement is usually not correlated to skin activity and may present years after the disease initial symptomatology. In 16% of cases, neurologic symptoms predate the cutaneous manifestations.
Neurological symptoms and signs in LScs are protean and include epilepsy, headache, focal neurological deficits, and movement disorders, as well as neuropsychiatric symptoms and intellectual deterioration. In regards to headaches, around 35% of LScs patients refer headache, which is usually associated with other neurologic complaints. Few studies have investigated headache subtype, but migraines and mimics of hemiplegic migraine seem to be more prevalent.

Precipitants

None

Provocation Tests

None

Diagnostic Procedures

The diagnosis is clinical and based on characteristic cutaneous and soft tissue findings. Currently no diagnostic laboratory tests exist. Nonetheless, 37 to 50% of the patients may present a positive ANA test (homogenous or speckled patterns), as well as anti-single-stranded-DNA antibodies. Antinucleosome antibodies, soluble interleukine-2 receptor, and, recently, antiagalactosyl immunoglobulin G antibodies have been reported in LS.