A 60-year-old man presents with generalized onset of fish-like scaling over the trunk and extremities without preceding skin disease. There is no family history of similar complaints. The most important investigation to perform next is:

• A Skin biopsy for direct immunofluorescence
• B Serum antinuclear antibody profile
• C Age-appropriate malignancy screening including lymph node examination ✓
• D Serum IgE and filaggrin gene mutation analysis

Explanation

Acquired ichthyosis in an adult, especially when late onset and without family history, should raise suspicion for underlying malignancy, most commonly Hodgkin lymphoma and other lymphoreticular malignancies. It can also occur with sarcoidosis and nutritional deficiencies. Filaggrin testing is relevant for congenital ichthyosis vulgaris. Direct immunofluorescence and ANA are not the primary concern here.

Reference: Rook's Textbook of Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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