What is the key symptom that indicates the need for intervention in cases of lichen planus?

The key symptom indicating the need for intervention in cases of lichen planus is persistent lesions. Lichen planus is characterized by various lesions that can appear on the skin, mucous membranes, hair, and nails. While presence of Wickham's striae, which are fine white lines often seen on lesions, can be a notable feature of the condition, it does not independently trigger the necessity for intervention.

The absence of discomfort may even suggest a non-aggressive form of the disease, thus not necessitating immediate treatment. On the other hand, a positive biopsy provides confirmation of the diagnosis but does not inherently indicate that intervention is required. Persistent lesions, however, may signify that the condition is not resolving on its own and may require therapeutic measures to manage symptoms, prevent complications, or address the impact on the patient's quality of life.