A 45-year-old Caucasian woman presented with pruritic erythematous scaling eruptions on her back and lower extremities. The patient said these skin lesions, which she has had since childhood, become worse in the summer. Additionally, her nails were fragile and often cracked. Her father and son had similar skin lesions.
On skin examination, we saw erythematous hyperkeratotic confluent papules and plaques on her back, chest, thighs, and lower legs. Multiple 3- to 5-mm keratotic papules were noted on the dorsa of her hands bilaterally. Fingernail examination revealed longitudinal lines with notching at the distal edges (Figures 1 and 2). Examination of other systems was unremarkable.
FIGURE 1
Papules on the back...
FIGURE 2
...and the thighs
What is your diagnosis?
Are any diagnostic tests Necessary to confirm it?