The correct answer is: B. Type 2 collagen.

Explanation: The image shows relapsing polychondritis (see image Figure 2.1.41 in DIR). This condition occurs in the 4th-5th decade and is likely secondary to antibodies directed towards type 2 cartilage. Type 2 cartilage is found in articular and non-articular cartilage, and this condition can lead to chondrolysis, dystrophy, and atrophy of cartilage with sparing of the earlobe. This can lead to erythema, edema, and pain with flares lasting 1-2 weeks, and the recurrent episodes can lead to permanent cartilage destruction and fibrosis (i.e. cauliflower ear).

A. Type 1 collagen is not the most common type of collagen involved in relapsing polychondritis B. Type 2 collagen is the correct answer. C. Type 3 collagen is not the most common type of collagen involved in relapsing polychondritis D. Type 4 collagen is not the most common type of collagen involved in relapsing polychondritis E. Type 5 collagen is not the most common type of collagen involved in relapsing polychondritis.

References:

General Dermatology 2.1 Neutrophilic Disorders DIR Review book page 76