What is the most likely etiology for the erosive lichen planus presentation in this case?

• A. Autoimmune
• B. Bacterial infection
• C. Viral infection
• D. Fungal infection

Answer: (A)

The main idea here is that erosive lichen planus is an immune-mediated condition. It involves a T-cell–driven attack on the basal cells of the oral mucosa, leading to damage at the dermal-epidermal junction. This cytotoxic T-cell response causes basal cell degeneration and the formation of Civatte bodies, producing the characteristic erosive and painful mucosal lesions seen in this variant. While conditions like hepatitis C can be associated with lichen planus, the underlying cause is not a direct viral infection; it’s the autoimmune/immune-mediated process that drives the disease. Infections can complicate the erosions (for example, secondary candidiasis), but they are not the primary etiology.