A 43-year-old woman with a history of guttate psoriasis presents with swollen fingers and toes. What is the most likely diagnosis?

In this scenario, the clinical presentation of the 43-year-old woman along with her history of guttate psoriasis strongly points toward psoriatic arthritis as the most likely diagnosis.

Guttate psoriasis is a specific type of psoriasis characterized by small, drop-shaped lesions, often triggered by infections such as streptococcal throat infections. Individuals with psoriasis have an increased risk of developing psoriatic arthritis, which commonly manifests with symptoms such as swollen fingers and toes, often referred to as "dactylitis" or "sausage digits."

The swelling in the fingers and toes suggests that there is an inflammatory process occurring, which is consistent with psoriatic arthritis. The overlap of her psoriasis and the current presentation of swelling supports this diagnosis.

In contrast, conditions such as osteoarthritis typically involve joint pain and stiffness but are less likely associated with significant swelling of the fingers and toes in such a manner and are generally seen in older individuals or those with a history of joint trauma. Rheumatoid arthritis could be a consideration, but it usually presents with symmetrical joint swelling and morning stiffness, rather than isolated swelling of the digits without significant involvement of other joints. Systemic lupus erythematosus is also less likely in this context, as