Random Dermatology MCQ - Behçet’s disease

A 45-year-old woman presents with recurrent oral ulcers, genital ulcers, and erythema nodosum-like lesions on her legs. Ocular examination reveals anterior uveitis. Which of the following HLA associations is most strongly linked to this condition?

A) HLA-B27
B) HLA-Cw6
C) HLA-B51
D) HLA-DR4
E) HLA-A29

Correct Answer: C) HLA-B51

Explanation

This patient has Behçet’s disease, a multisystem vasculitis characterized by the triad of oral aphthae, genital ulcers, and uveitis. Other features include pathergy, erythema nodosum-like lesions, and neurologic involvement.

• HLA-B51 is the strongest genetic association (up to 80% of patients in endemic regions like the Middle East/Asia).

• HLA-B27 (A): Associated with ankylosing spondylitis/reactive arthritis.

• HLA-Cw6 (B): Linked to psoriasis vulgaris.

• HLA-DR4 (D): Seen in pemphigus vulgaris and rheumatoid arthritis.

• HLA-A29 (E): Birdshot chorioretinopathy.

Key point: Behçet’s is a neutrophilic vasculitis with pathergy (hyperreactivity to skin trauma), and HLA-B51 screening can support diagnosis in uncertain cases.