A 50-year-old woman presents with recurring episodes of pain and stiffness primarily in her finger joints, which are more pronounced in the morning and last for about 15 minutes. She also experiences shortness of breath, a cough and fatigue, particularly after exposure to cold showers. Additionally, she notices pallor in the skin of her fingers during these cold episodes. The patient denies having oral ulcers, photosensitivity, alopecia, dry mouth, or dry skin. She does not smoke or consume alcohol. Her medical history includes well-controlled hypertension with medication. She has no other significant medical conditions.

On examination, her blood pressure is 120/80 mmHg, pulse is 80/min, respiratory rate is 16/min, and SpO2 is 98% on room air. Cardiovascular examination reveals normal heart sounds with no murmurs, rubs, or gallops. Respiratory examination reveals fine inspiratory crackles at the lung bases, suggestive of lung fibrosis. She has tenderness and swelling primarily in the finger joints, and to a lesser extent in the wrists, elbows, and knees. The range of motion in the affected joints is limited. Her fingers are puffy with thickening and tightening of the skin. The skin on her arms up to her axillae is firm with areas of subtle increase and decrease in pigment. No evidence of ulcers or telangiectasia is observed.

Which one of the following is the most likely diagnosis?
Choose the single best answer.

• Diffuse systemic sclerosis

• Antiphospholipid syndrome

• CREST syndrome

• Sine scleroderma

• Overlap syndrome