Differential Diagnosis for a 70-year-old Female with Weak Positive Anti-centromere Antibodies and Generalized Pruritis

• Single most likely diagnosis:
  • Limited Systemic Sclerosis (CREST syndrome): This diagnosis is likely due to the presence of anti-centromere antibodies, which are highly specific for limited systemic sclerosis. Generalized pruritis can be an early symptom of this condition. Although the antibody titer is described as weakly positive, the clinical correlation with other symptoms such as pruritis, potential skin thickening, and possibly esophageal dysmotility or other systemic features, makes this a strong consideration.
• Other Likely diagnoses:
  • Primary Biliary Cholangitis (PBC): This autoimmune liver disease can present with pruritis and has been associated with various autoantibodies, including anti-centromere antibodies in some cases. The age and sex of the patient also align with the typical demographic for PBC.
  • Mixed Connective Tissue Disease: While less likely than limited systemic sclerosis given the specific mention of anti-centromere antibodies, mixed connective tissue disease can present with a variety of autoantibodies and symptoms overlapping with different autoimmune diseases, including pruritis.
• Do Not Miss diagnoses:
  • Lymphoma: Certain types of lymphoma, particularly cutaneous T-cell lymphoma (e.g., mycosis fungoides, Sézary syndrome), can present with generalized pruritis. Although anti-centromere antibodies are not typically associated with lymphoma, the severity of pruritis and potential for lymphoma to mimic other diseases make it a "do not miss" diagnosis due to its significant implications for treatment and prognosis.
  • Hepatobiliary Disease (e.g., Cholestasis): Conditions causing cholestasis, such as primary sclerosing cholangitis or drug-induced cholestasis, can lead to severe pruritis. While anti-centromere antibodies are not directly related to these conditions, the symptom of pruritis necessitates considering hepatobiliary causes, especially given the potential for serious underlying disease.
• Rare diagnoses:
  • Sjögren's Syndrome: Although primarily known for causing dry eyes and mouth, Sjögren's syndrome can occasionally present with pruritis. The presence of anti-centromere antibodies is less common in Sjögren's but can occur, making this a rare consideration in the differential diagnosis.
  • Eosinophilic Fasciitis: This rare condition can cause skin thickening and pruritis, among other symptoms. While it does not typically present with anti-centromere antibodies, its rarity and potential for significant morbidity if untreated make it a consideration in a broad differential diagnosis.