This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of skin, Subject name: Dental
Nail pitting is caused by all except - 
Select and explain. 
A. Lichen planus, B. Psoriasis, C. Alopecia areata, D. Pityriasis Rosacea
D: Pityriasis Rosacea
Answer: D: Pityriasis Rosacea 
Explanation: Nail involvement is common in alopecia areata, paicularly in severe forms. Pitting is the most common finding, but other abnormalities such as trachyonychia have been repoed. Nail plate pitting tends to be more shallow and regularly spaced than in psori-atic nail pitting Nail pitting is often a sign of another condition that can include: psoriasis, which causes skin inflammation. reactive ahritis or inflammation caused by an infection elsewhere. alopecia areata, which causes temporary bald patches on the scalp. Ref Harrison20th edition pg 1278