Can psoriasis cause axillary lymphadenopathy?

Psoriasis and Axillary Lymphadenopathy

Psoriasis itself does not typically cause axillary lymphadenopathy, and the presence of axillary lymph node enlargement in a patient with psoriasis should prompt investigation for other causes. 1

Understanding the Relationship Between Psoriasis and Lymph Nodes

Psoriasis is a chronic, immune-mediated, systemic inflammatory disorder that primarily affects the skin but can also involve other organ systems. While psoriasis has several manifestations and comorbidities, axillary lymphadenopathy is not a recognized direct manifestation of the disease itself.

Key points about psoriasis and lymph node involvement:

• Psoriasis is characterized by scaly, erythematous patches, papules, and plaques that can affect various body areas, including the axillary region (as inverse psoriasis) 1
• Inverse psoriasis specifically affects skin folds including axillary areas, presenting as erythematous plaques with minimal scale due to the moist nature of these areas 1
• While psoriasis involves immune system dysregulation with increased T-cell activity, this does not typically manifest as clinically detectable lymphadenopathy 2

Differential Diagnosis for Axillary Lymphadenopathy in Psoriasis Patients

When axillary lymphadenopathy is present in a patient with psoriasis, other causes should be considered:

1. Infection/Inflammation:

   • Localized infections in the arm, hand, or axillary region
   • Systemic infections
   • Inflammatory conditions affecting the lymphatic system 1

2. Malignancy:

   • Lymphoma - patients with psoriasis have an increased risk of developing lymphoma, particularly Hodgkin's lymphoma (RR 3.18) and cutaneous T-cell lymphoma (RR 10.75) 3, 1
   • Breast cancer - the most common cause of malignant axillary lymphadenopathy 1
   • Other solid tumors with metastasis to axillary nodes

3. Treatment-Related:

   • Lymphadenopathy as a side effect of psoriasis treatments (e.g., certain biologics or immunosuppressants) 1

4. Coincidental:

   • Benign reactive lymphadenopathy from various causes unrelated to psoriasis 1

Evaluation of Axillary Lymphadenopathy in Psoriasis Patients

When a patient with psoriasis presents with axillary lymphadenopathy, a systematic approach is recommended:

1. Complete clinical evaluation:

   • Assess for other sites of adenopathy
   • Evaluate potential non-psoriasis etiologies of adenopathy 1

2. Age-appropriate diagnostic imaging:

   • For patients ≥30 years: Ultrasound with mammogram
   • For patients <30 years: Ultrasound 1

3. Tissue sampling:

   • Core needle biopsy for palpable axillary mass that is suspicious on imaging
   • Consider special pathologic evaluation if lymphoma is suspected 1

Clinical Implications

The presence of axillary lymphadenopathy in a patient with psoriasis should raise concern for:

• Possible development of lymphoma, as psoriasis patients have an increased risk (though the absolute risk remains low at approximately 7.9/100,000 psoriasis patients per year) 3
• Potential breast malignancy or other solid tumor with metastasis
• Infection or inflammatory condition requiring specific treatment

Conclusion

While psoriasis is associated with various comorbidities and can affect the axillary region as inverse psoriasis, it does not directly cause axillary lymphadenopathy. Finding enlarged axillary lymph nodes in a psoriasis patient warrants appropriate investigation for other causes, particularly given the increased risk of lymphoma in this population.