Dermatology MCQ - Inflammatory Dermatoses - Systemic sclerosis signs and symptoms

A 58-year-old woman presents with a 3-year history of tightening and thickening of the skin on her hands, arms, and face. She also reports severe Raynaud's phenomenon and dysphagia. On physical examination, which of the following findings is considered the single most specific clinical sign for the diagnosis of systemic sclerosis?

A. Digital pitting scars
B. Calcinosis cutis
C. Sclerodactyly
D. Mat-like telangiectasias
E. Loss of the radial eyebrow hair (Queen Anne's sign)

Correct Answer: C. Sclerodactyly

Explanation

Systemic sclerosis (scleroderma) has a wide range of cutaneous manifestations, but some are more specific than others. Sclerodactyly refers to the localized thickening and tightening of the skin distal to the metacarpophalangeal joints (i.e., the fingers).

• Pathognomonic Sign: While many signs are highly characteristic, sclerodactyly is often considered the single most specific cutaneous finding for systemic sclerosis. It is a cardinal feature and is included in the classification criteria for the disease. It represents the fibrotic process that is central to the pathophysiology of scleroderma.

Why other options are incorrect

• A. Digital pitting scars: These are very common and characteristic of systemic sclerosis, resulting from ischemic damage due to the vascular pathology. However, they can also be seen in other conditions causing digital ischemia.

• B. Calcinosis cutis: The deposition of calcium in the skin and subcutaneous tissues is a classic feature of the CREST syndrome (limited cutaneous) subset. While highly suggestive, it can also occur in dermatomyositis and other conditions.

• D. Mat-like telangiectasias: These are flat, macular telangiectasias that are highly characteristic of systemic sclerosis, especially the limited cutaneous variant. However, telangiectasias can be seen in other diseases (e.g., hereditary hemorrhagic telangiectasia, chronic sun damage).

• E. Loss of the radial eyebrow hair (Queen Anne's sign): This is a sign of secondary syphilis, not systemic sclerosis. The hair loss in scleroderma typically affects the scalp, leading to non-scarring alopecia, not a specific pattern on the eyebrows.

Key Associations for Systemic Sclerosis Signs & Symptoms

• Vascular Phenomena:

  • Raynaud's phenomenon: Often the very first symptom, present in over 95% of patients.

  • Digital ulcers: A major cause of morbidity.

• Cutaneous Manifestations (The "CREST" Syndrome for Limited SSc):

  • Calcinosis

  • Raynaud's phenomenon

  • Esophageal dysmotility (part of the systemic GI involvement)

  • Sclerodactyly

  • Telangiectasias

• Systemic & Organ-Specific Manifestations:

  • Gastrointestinal: Dysphagia (due to esophageal hypomotility), gastroesophageal reflux disease (GERD), constipation, bacterial overgrowth.

  • Pulmonary: Interstitial Lung Disease (ILD) and Pulmonary Arterial Hypertension (PAH) are the leading causes of mortality.

  • Renal: Scleroderma Renal Crisis (SRC), a medical emergency characterized by malignant hypertension and acute kidney injury, often associated with anti-RNA polymerase III antibodies.

  • Cardiac: Myocardial fibrosis, pericarditis, conduction abnormalities.

• Autoantibodies and Subsets:

  • Anti-Centromere: Strongly associated with limited cutaneous SSc and a lower risk of ILD but a higher risk of PAH.

  • Anti-Scl-70 (Topoisomerase I): Strongly associated with diffuse cutaneous SSc and a high risk of progressive Interstitial Lung Disease.

  • Anti-RNA Polymerase III: Associated with diffuse cutaneous SSc and a high risk of Scleroderma Renal Crisis.