When to Suspect Hidradenitis Suppurativa

NOVEMBER 15, 2016
MD Magazine Staff

Hidradenitis suppurativa is a chronic skin disease associated with severe symptoms and complications. Early diagnosis and treatment can improve disease control and overall quality of life. Robert G. Micheletti, MD, discusses the impact of the disease and provides insight on its optimal management.
Robert G. Micheletti, MD: I think many dermatologists feel like they know hidradenitis when they see it, but sometimes we see atypical presentations or presentations that we’re not expecting. For the emergency medicine provider or the primary care physician who commonly sees infection walking through the door, it’s really important to be able to define what hidradenitis is, how it presents, and how we make a diagnosis. The way I like to summarize this is by saying that we are looking for characteristic lesions in characteristic locations that are recurring or cyclical over time. So, when we talk about characteristic lesions, what we are looking for is anything ranging from comedones; so, blackheads that appear in typical areas. Sometimes we talk about the double-headed comedone, this comedone that is dual-headed. That is very characteristic for hidradenitis, and it speaks to that follicular occlusion that’s happening.
As the disease progresses, you start to see inflammatory papules or nodules, so-called boils that may drain. Then, as it progresses still further, you can get sinus tract formation that’s fibrous-scarring that is really under the skin. If you press with your hand, you’ll feel this fibrous tissue. You might see purulent material being expressed from a remote location away from where you’re pressing. And then, even in very severe disease, you’ll see actually an entire anatomic area that can be involved with this scarring and sinus tract formation.
Some patients have very, very severe disease, where you have almost an erosive necrotic appearance where the entire area is really falling apart. In terms of location, we think about anything along the milk line as being typical, so that goes from axillae, under the breasts, the groin area, and then wrapping around the perineum. So, anything along those lines, it tends to be typical for hidradenitis. You’re really looking for bilateral disease. If someone has 1 boil ever and it’s in one axilla, that may or may not be hidradenitis. If I saw maybe open comedones, blackheads on the other side, then I might be suspicious that they’re on the hidradenitis spectrum. But, really you’re looking for bilateral disease and you’re looking for it to be recurring over time, so that if somebody is coming in for the third incision and drainage and it’s happening in both arm pits, that would be very suggestive. And so, we want to make sure that we’re on the lookout for patients like that who, really, it’s not just a bacterial issue, a staph abscess, or whatever, but rather actual hidradenitis suppurativa.
Again, I’m looking for characteristic lesions, characteristic locations along the milk line, bilateral and recurring over time. If I don’t have those things, if it’s just one side of say the buttock that’s involved, that’s when I’m looking for something else. Maybe this is an atypical infection, maybe I need to do a biopsy, do a tissue culture, something of that nature just to rule out other things. That kind of hidradenitis atypical presentation does occur, but we want to be making sure that it really is hidradenitis when we’re seeing that. Now, biopsy itself is not diagnostic. Biopsies can be variable depending on what sort of lesion you’re biopsying, and they’re not going to be definitive. But if you’re thinking about ruling something else out, they can be helpful.
I think for the community physician who’s not a referral dermatologist, getting patients sent over for suspicion of hidradenitis, I think it is important to know what to look for. Looking for lesions that are typical, these open comedones, these inflammatory cystic nodules, bilateral, recurring in the characteristic distribution from axilla to groin, those are the things that we’re thinking about. Again, certainly as a community physician, if you’re seeing a patient over time and you’re seeing that they’re having recurring issues with that, that’s very helpful. It is a challenge in the ER because you’re not getting that same continuity.
But if you can take a history to see if this is something that is happening over and over, if they’re just showing you one area, say the right axilla, looking on the left, looking in the groin, seeing if you see something as minimal as these blackheads there that you see in the inner thighs or in other areas, those things can be useful clues to hidradenitis. I would say that you’re not going to go wrong by suspecting the diagnosis, and referring or suspecting the diagnosis, and initiating some appropriate hidradenitis suppurativa treatment. Nobody is going to say that you did something wrong, whereas if you miss the diagnosis—and I should say here that the average delay in diagnosis for these patients is about 7 years—if you miss the diagnosis, that’s a problem. I think if you are suspicious and you prefer to start a treatment on your own that’s appropriate for hidradenitis, then no one is going to be unhappy with you. I think that certainly is a consult that we’re happy to get as dermatologists.

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