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<v ->Now another characteristic of the spondyloarthropathies

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you already heard about is the finding of dactylitis.

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And in simple terms, dactylitis means inflammation

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of a finger or of a toe.

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Now there are many causes of dactylitis,

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this is a short list of some of them,

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of course, we're talking about spondyloarthropathies,

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where dactylitis can relate to tenosynovitis,

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osteitis, or soft issue inflammation.

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But one can get dactylitis in sarcoid,

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one can get it in tuberculosis,

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we saw in syphilis, we heard about in syphilis,

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how you can get that, other infections,

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sickle cell anemia, osteoid osteoma.

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Going to time element,

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I'm not gonna show you examples

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of all these producing dactylitis,

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we're gonna concentrate on the spondyloarthropathies.

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But be aware that there are many conditions

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that lead to inflammation of a finger or of a toe.

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Single or multiple digits, of course,

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and the pathology of them,

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the pathogenesis of why it occurs different

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in these various diseases.

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So let's look at a classic example of psoriatic dactylitis.

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In my experience the most common site to find this,

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is in the foot, it's in the great toe,

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it's in the terminal phalanx of the great toe,

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and it leads to a finding

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that we initially called an ivory phalanx.

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The most common cause of an ivory phalanx,

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a white, dense phalanx, in my experience,

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is psoriatic dactylitis.

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Now you can see it with osteomyelitis,

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you can see it with other conditions as well.

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But the first thing I think about when I see

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an ivory phalanx in the foot, particularly in the great toe,

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is spondyloarthropathy, and especially related to psoriasis.

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It's said to occur in up to a quarter of patients

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who have psoriasis,

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particularly those who have severe disease,

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with a lot of erosions.

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Again, more common in the feet than in the hand,

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it can be multiple digits and when you study it with MR,

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low signal becoming high signal

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with fluid sensitive sequences

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indicative of the bone proliferation

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that is occurring in that area.