Keratoerma blennorhagicum is unique to which type of arthritis?

• A. Psoriatic arthritis
• B. Reactive arthritis
• C. Rheumatoid arthritis
• D. Gout

Answer: (B)

Keratoerma blennorhagicum is a skin condition that presents as hyperkeratotic lesions and is specifically associated with reactive arthritis, particularly following infection with certain urethral bacteria such as Chlamydia. Reactive arthritis is characterized by inflammation that occurs in response to an infection in another part of the body, commonly the genitourinary system.

This specific skin manifestation is considered one of the hallmark signs of reactive arthritis, reinforcing the link between the immune response triggered by an infection and the subsequent development of arthritis symptoms. The lesions can develop on the palms and soles and are often painless.

In contrast, the other types of arthritis listed do not have this specific dermatological presentation linked to them. For example, psoriatic arthritis is associated with skin psoriasis but not keratoerma blennorhagicum, while rheumatoid arthritis and gout have their respective clinical features that do not include this particular skin condition. Therefore, recognizing keratoerma blennorhagicum as a unique manifestation of reactive arthritis is crucial for differential diagnosis in clinical practice.