Dermal fibrosis is a condition where the skin’s dermal layer undergoes excessive scarring. It involves an overactivity of fibroblast cells, which produce an abundance of collagen and other extracellular matrix proteins. This leads to noticeable thickening and hardening of the affected skin tissue. This accumulation of fibrous connective tissue can occur in the dermis or subcutis, often with chronic inflammation.
Underlying Causes and Triggers
Various factors can initiate dermal fibrosis. Tissue injury is a common initiator, where normal wound healing can become dysregulated. This can result in hypertrophic scars, which are raised and red but remain within the original wound, or keloids, which extend beyond the wound site and can continue to grow. In these cases, fibroblasts produce excessive collagen and other extracellular matrix components, driven by growth factors like TGF-β.
Autoimmune conditions are another cause, where the immune system mistakenly attacks healthy tissues. Diseases such as systemic sclerosis (scleroderma) and morphea involve the immune system triggering a chronic fibrotic response in the skin. Morphea leads to hardening of the skin due to increased collagen deposition. Systemic sclerosis also involves excessive collagen production and accumulation in the skin and internal organs.
Genetic factors play a role in the predisposition to certain fibrotic conditions. Some individuals have an inherited tendency to develop keloids after skin injury, with a higher incidence observed in people of African and Asian descent. Studies suggest multiple genetic and epigenetic factors may contribute to keloid pathogenesis.
Other triggers for dermal fibrosis include radiation therapy, which can lead to radiation-induced fibrosis. This typically develops within 4 to 12 months after therapy but can progress for many years. Nephrogenic systemic fibrosis is another cause, linked to gadolinium exposure in patients with kidney insufficiency. This condition involves fibrosis of the skin and internal organs, leading to painful skin thickening and joint contractures.
Physical Signs and Symptoms
Dermal fibrosis manifests through changes in skin texture. The affected skin often becomes hardened, a condition known as induration, and appears thickened. It can also develop a tight, waxy, or shiny appearance, with some cases exhibiting a “woody” texture or an “orange-peel” dimpling.
The loss of skin elasticity is a consequence of dermal fibrosis, which can significantly restrict movement. When fibrosis occurs over joints, such as the hands, wrists, ankles, or knees, it can lead to severe flexion contractures and a substantial reduction in range of motion. This can impair functional mobility.
Changes in skin color are also observed in affected areas. This can include both darkening, known as hyperpigmentation, and lightening, or hypopigmentation. For example, in nephrogenic systemic fibrosis, reddened or darkened patches may appear on the skin.
Individuals with dermal fibrosis may also experience itching, a symptom known as pruritus, or pain in the affected skin. These sensations can impact a person’s quality of life.
The Diagnostic Process
Confirming a diagnosis of dermal fibrosis involves several steps. A clinical examination is often the initial approach, where a dermatologist visually inspects and physically feels, or palpates, the skin. This assessment helps determine the texture, thickness, and boundaries of the affected areas. Objective tools like the SkinFibroMeter can also be used to measure skin stiffness and induration, providing quantitative data to assess the severity of fibrosis.
A skin biopsy is considered the definitive method for diagnosis. A small sample of the affected skin is taken and then examined under a microscope by a pathologist. This microscopic analysis identifies characteristic features, such as excessive collagen deposits, an increased number of fibroblasts, and disorganized collagen fibers, which confirm the presence of fibrosis.
Blood tests may also be ordered, not to directly diagnose fibrosis, but to check for underlying conditions. For instance, in suspected autoimmune diseases like scleroderma, blood work can reveal autoantibodies or other markers that indicate immune system dysfunction. Antinuclear antibody (ANA) testing is often performed, and if positive, more specific autoantibodies related to scleroderma may be tested.
Medical Management Approaches
Managing dermal fibrosis aims to slow its progression, alleviate symptoms, and improve functional abilities. Complete reversal can be challenging.
Topical treatments are often a first line for localized fibrosis, including creams and ointments containing corticosteroids and retinoids. Corticosteroids help reduce inflammation, while retinoids can help soften the skin and may prevent corticosteroid-induced skin atrophy.
Intralesional therapy involves injecting medications directly into localized fibrotic lesions. Triamcinolone acetonide, a corticosteroid, is commonly injected into keloids to suppress inflammation and reduce scar volume. This approach can flatten lesions and reduce associated pain and itching. Combining corticosteroids with other agents like 5-fluorouracil can enhance effectiveness and reduce side effects.
For more widespread or aggressive fibrosis, systemic medications are employed. These include immunosuppressants such as methotrexate, which can be taken orally or by injection. Newer antifibrotic agents are also used to reduce fibrosis, particularly in conditions like systemic sclerosis.
Phototherapy, using ultraviolet A1 (UVA-1) light, can help soften hardened skin. UVA-1 penetrates deeper into the skin and can reduce inflammation and decrease dermal thickness by affecting immune dysregulation and collagen metabolism. This treatment has shown efficacy in conditions like morphea and systemic sclerosis, with some patients experiencing skin softening and improved mobility.
Supportive therapies play a role in maintaining function and preventing further complications. Physical and occupational therapy are frequently recommended to maintain range of motion and prevent joint contractures through stretching and exercise. These therapies improve joint mobility and can involve active or passive exercises, splinting, and orthoses to stretch shortened tissues.