What is morphea (localized scleroderma)?

What is Morphea (Localized Scleroderma)?

Morphea, also known as localized scleroderma, is a chronic autoimmune fibrosing disorder characterized by sclerotic skin lesions with thickening and hardening due to excessive collagen deposition that primarily affects the skin and underlying subcutaneous tissues (fat, fascia, muscle, and bone), but unlike systemic sclerosis, does not involve internal organs. 1, 2

Clinical Classification

Morphea is classified into five distinct subtypes based on distribution and depth of involvement 1:

• Circumscribed morphea: Limited, superficial plaques that are the most common presentation and typically resolve within 3 years 3
• Linear scleroderma: Linear sclerotic plaques that can be particularly severe in children, especially when affecting the face (en coupe de sabre variant) or extremities, with potential for permanent functional disability and cosmetic disfigurement 1, 4
• Generalized morphea: Extensive involvement affecting large body surface areas 1
• Pansclerotic morphea: The most severe form involving deep tissues including fascia and muscle 1, 5
• Mixed subtype: Combination of two or more of the above subtypes 1

Epidemiology and Pathogenesis

• Morphea is ten times more prevalent than systemic sclerosis, with an incidence of approximately 3.4 cases per million children per year 6, 3
• The exact pathogenesis remains unknown, but involves immunologically triggered release of pro-inflammatory cytokines in genetically predisposed individuals, leading to profound dysregulation of connective tissue metabolism and ultimately fibrosis 2
• Linear morphea en coupe de sabre can arise in adulthood in about 32% of cases, showing a more aggressive course with increased risk of systemic involvement compared to childhood-onset disease 7

Clinical Significance and Prognosis

The significance of morphea depends critically on the extent of lesions, potential for functional disability or cosmetic disfigurement, and presence of extracutaneous manifestations. 4

• Superficial circumscribed forms generally have good prognosis and may resolve spontaneously within 3 years 3
• Linear forms, particularly those affecting the face and extremities, can be severely deforming and irreversibly disabling 4
• Recurrence rates are substantial at 25-48% in the first years after treatment discontinuation, necessitating long-term follow-up 6
• The disease is associated with significant physical and psychological morbidity that should not be underestimated 8

Diagnostic Approach

All patients with suspected localized scleroderma should be referred to a specialized rheumatology center (pediatric rheumatology for children) for comprehensive evaluation. 1, 6

Clinical Assessment

• Complete skin examination to identify sclerotic plaques, active inflammatory lesions, and architectural changes, documented with diagrams or photography 6
• The Localized Scleroderma Cutaneous Assessment Tool (LoSCAT) is highly recommended for standardized assessment, which includes the LoSSI (Localized Scleroderma Skin Severity Index) for measuring disease activity and the LoSDI (Localized Scleroderma Skin Damage Index) for measuring damage 1, 8, 6

Confirmatory Testing

• Skin biopsy from the most active sclerotic area should be performed when diagnostic uncertainty exists, atypical features are present, or features mimic other conditions like lichen sclerosus 8
• Histopathology is required in most cases to determine the depth and degree of tissue involvement 5
• There are no specific serological markers clearly associated with morphea, and in the absence of symptoms suggesting systemic involvement, extensive laboratory examinations are purposeless 2, 3

Extracutaneous Evaluation

For patients with linear morphea involving the face and head 1:

• MRI of the head is highly recommended at diagnosis, with or without signs of neurological involvement 1
• Ophthalmological assessment including screening for uveitis at diagnosis and during follow-up 1
• Orthodontic and maxillofacial evaluation at diagnosis and during follow-up 1

For all patients 1:

• Complete joint examination including the temporomandibular joint at diagnosis and follow-up 1
• MRI can be useful to assess musculoskeletal involvement, especially when lesions cross joints 1

Common Diagnostic Pitfalls

• Mistaking morphea for other conditions such as lichen sclerosus, especially in extragenital sites, is a common error 8
• Underestimating the importance of extracutaneous involvement, particularly in linear forms affecting the face and extremities 1