A 28-year-old woman presents to the dermatology clinic with a three-month history of itchy, scaly, red papules on her forearms, lower legs, and upper back. The lesions started as small bumps but gradually became more numerous and have a rough, scaly texture. She reports that the rash worsens after sun exposure and that she occasionally experiences mild burning or stinging sensations.

She denies fever, joint pain, or systemic symptoms but has a history of atopic dermatitis as a child. She has not used any new skincare products or medications. Examination reveals multiple well-demarcated, erythematous papules with fine scaling, some coalescing into plaques. The lesions spare the palms, soles, and mucous membranes. There is no evidence of vesicles, pustules, or ulceration.

A diagnosis of lichen planus with papulosquamous eruption is considered. A skin biopsy is recommended for confirmation, and the patient is started on a regimen of topical corticosteroids and antihistamines for symptom relief. She is advised to avoid potential triggers, including excessive sun exposure and harsh soaps.