Can scleroderma cause leukocytosis (an increase in white blood cell count)?

Can Scleroderma Cause Leukocytosis?

Yes, scleroderma can cause leukocytosis, though it is not a typical or common manifestation of the disease. When present, leukocytosis in scleroderma patients typically signals specific complications or disease activity patterns that require clinical attention.

Frequency and Clinical Context

• Leukocytosis occurs in approximately 14% of scleroderma patients 1
• When leukocytosis is present, it is correlated with active myopathy and/or advanced visceral involvement 1
• This finding is relatively uncommon compared to other hematologic abnormalities in scleroderma, where anemia (25%) is more frequent 1

Clinical Significance and Associated Conditions

Active inflammatory complications are the primary drivers of leukocytosis in scleroderma:

• Active myopathy/myositis: Patients with inflammatory muscle involvement are more likely to demonstrate elevated white blood cell counts 1
• Advanced visceral organ involvement: Progressive internal organ disease correlates with leukocytosis 1
• Overlap syndromes: Anemia in scleroderma is often attributed to chronic inflammatory disease, particularly overlap syndromes, which may also contribute to leukocytosis 1

Important Clinical Pitfalls

Leukopenia, not leukocytosis, may suggest overlap with systemic lupus erythematosus (SLE) 1. This is a critical distinction because:

• Severe leukopenia and lymphopenia in SLE are associated with increased risk of infections 2
• The presence of leukopenia should prompt evaluation for SLE overlap rather than isolated scleroderma

Infection must be excluded when leukocytosis is present, particularly in patients on immunosuppressive therapy 2. In the context of connective tissue diseases, significantly elevated inflammatory markers alongside leukocytosis should raise suspicion for superimposed infection.

Monitoring Recommendations

When leukocytosis is detected in scleroderma patients:

• Evaluate for active myopathy: Check muscle enzymes (CK, aldolase) and consider muscle imaging or biopsy if inflammatory myositis is suspected 1
• Assess for visceral organ progression: Screen for worsening interstitial lung disease, cardiac involvement, or renal complications 2, 1
• Rule out infection: Particularly important in patients receiving immunosuppressive therapy for scleroderma complications 2
• Consider overlap syndromes: Evaluate for features of other connective tissue diseases that may coexist with scleroderma 1