This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Least common site involvement in psoriasis is – 
Select and explain. 
A. Scalp, B. Nail involvement, C. CNS involvement, D. Arthritis
C: CNS involvement
Answer: C: CNS involvement 
Explanation: Not found in psoriasis

Alopecia (despite the involvement of scalp)
Face involvement (though scalp lesion can extend on forehead
Mucosal involvement

Uncommon in psoriasis

Joint involvement (5-10%)
Pruritis