Recognizing CTCL Symptoms After Dupixent

• Patches: flat, discolored, scaly areas that are often itchy and may appear on sun protected skin such as the trunk, hips, or buttocks.
• Plaques: thicker, raised, sometimes reddish patches that do not respond to typical eczema or psoriasis treatments.
• Tumors: raised nodules that may ulcerate. Reaching tumor stage is a threshold event associated with a significant drop in 5 year survival.
• Erythroderma: widespread redness and scaling covering more than 80 percent of the body, often with intense itch. This pattern is characteristic of Sézary syndrome.

• Severe, unrelenting itch (pruritus) that disrupts sleep.
• Skin lesions that change shape, color, or thickness over months.
• Swollen lymph nodes, especially in the neck, armpits, or groin.
• Hair loss in affected areas.
• Unexplained weight loss, fever, or night sweats in advanced disease.

Early mycosis fungoides is famously a great mimicker. It is frequently mistaken for eczema, psoriasis, contact dermatitis, tinea (fungal infection), vitiligo, or chronic dermatitis. Per the PROCLIPI study (Scarisbrick et al., 2019), 85.6 percent of patients experienced a diagnostic delay, with a median delay of 36 months between first symptoms and diagnosis.

There is no single test. Diagnosis combines clinical examination with skin biopsy histopathology (often multiple punch biopsies over time), immunohistochemistry for T cell markers (CD2, CD3, CD4, CD5, CD7, CD8), and T cell receptor clonality testing. For suspected Sézary syndrome, peripheral blood flow cytometry is used. Staging follows the TNMB system (tumor, node, metastasis, blood).