Thursday, October 17, 2019

21 year-old woman with solitary eschar

This 21 year-old college student presented with a 5 week history of an evolving lesion on the right leg.  She is in good health and takes no medications by mouth.  The lesion started with pruritus and pain and a solitary evolving bulla on her right leg.  She had walked through a wooded area the night before this developed. It has evolved into a dry eschar.  She has a history of a DVT on her right leg 2 years ago after tonsillectomy, bed rest and a long plane trip while on oral contraceptives.  To date, she has been treated with mupirocin ointment and a topical corticosteroid.

O/E: When seen there was a solitary 2 cm eschar on her right leg.  No erythema, no purulence.

September 8, 2019 a.m.

September 8, 2019 p.m.

September 9, 2019

September 28, 2019

October 9, 2019

October 16, 2019 (Date of visit)

Labs: Pending

Diagnosis: Eschar.  Etiologic considerations:
Envenomation – Brown Recluse Spider Bite
Echthyma gangrenosum
Pyoderma gangrenosum (Antiphospholipid syndrome)

A lesion such as this in a young healthy immunocompetent woman suggests an antecedent insult such as a brown recluse spider bite, but we have no history to confirm that.  She is being worked up for underlying disorders that might predispose to echthyma.  However the antecedent DVT makes one consider an underlying problem such as the antiphospholipid syndrome.

1.  What diagnoses do you entertain?
2.  At this time, what therapies do you recommend?

About Hydrocolloid Dressings.
1. Background.
2. Another useful resource on hydrogels.
3. Video Demonstration.

The rash that leads to eschar formation. Dunn C, Rosen T.
Clin Dermatol. 2019 Mar - Apr;37(2):99-108. Author information
Abstract:  When confronted with an existent or evolving eschar, the history is often the most important factor used to put the lesion into proper context. Determining whether the patient has a past medical history of significance, such as renal failure or diabetes mellitus, exposure to dead or live wildlife, or underwent a recent surgical procedure, can help differentiate between many etiologies of eschars. Similarly, the patient's overall clinical condition and the presence or absence of fever can allow infectious processes to be differentiated from other causes. This contribution is intended to help dermatologists identify and manage these various dermatologic conditions, as well as provide an algorithm that can be utilized when approaching a patient presenting with an eschar.  Full Text.


  1. From W.S. a recently retired general surgeon: "If the eschar is clean and dry and free of infection, I see no urgency to do anything immediately other than keeping it clean and dry; she could shower briefly, but never soak it. At 2cm it is too large to heal by secondary intention, and will probably require a small split-thickness skin graft for optimal appearance. But that graft would have the best chance of success once it has a healthy granulating base. While most general surgeons could do a satisfactory debridement, a graft is more in the purview of a plastic surgeon. I recommend having her see a plastic surgeon soon, though not emergently.

  2. From Professor Khalifa Sharquie, Baghdad: "There is nothing to worry as it was an acute insult and now resolving.It is most probably induced by bite such as spider as it is deep but not impetigo or icthyma.First attack of bullous fixed drug eruption due to forgotten tablet? is possibility.Regarding care nothing to do as it is resolving apart from topical antibiotic.

  3. From Dato Ong Cheng Leng (Malaysia): I haven’t seen it but your diagnosis of a brown recluse spider bite fits in well. It is not common in Malaysia but from what I read, fairly well known in your part of the world. The bite is typically unnoticed initially, usually in the wild where these nasty creatures are found. Initial annular margin with blistering at the centre followed by Eschar with necrosis and healing with a scar which is unavoidable. The size of the lesion is fortunately small at 2cm. Bigger one like 10cm has been reported.

    I would recommend a course of a good powerful intravenous antibiotics if possible, but then oral Bactrim at three tablets b.d. may suffice with God given immunological defence mechanism plus His healing hand.

  4. An internationally recognized wound care dermatologist suggested: "
    I would use a hydrocolloid dressing like duoderm or else a hydrogel. Leave on for at least 5 days at a time or until the dressing starts to peel off. She can shower etc without disrupting the dressing.
    For smaller wounds these dressings are available over the counter."
    [Accordingly we have uploaded three helpful videos on hydrocolloid dressings]

  5. from Roy Grekin, M.D. UCSF: Most likely spider bite or other insect, although some really intense exposure to an allergic or otherwise caustic contactant could cause this. Not so important now, the injury is the thing and whatever caused it is gone at this point. Moist occlusion is about all you can do and periodic debridement at weekly intervals to remove the fibrinoid material which retards epithelial ingrowth. You may need to anesthetize the area and use forceps and an iris scissors to really get the film off and get down to pure granulation tissue. I'd start debriding at the edges of the defect to promote the epithelial growth there first. Sometimes you need to stimulate the epithelium to start growing again as it can become sort of moribund or stagnant. A light curettage at the edge of the wound or a light application of 25% TCA may help to jump start the keratinocyte proliferation. Sometimes the necrotic tissue has also killed the nerve endings so you may get away without the anesthesia at first, but since you need to get to healthy granulations for the epithelium to grow across it eventually you may need to numb it. There are so many "biologic" occlusive and semi-occlusive dressings now that it is hard to give a definitive recommendation as to which is best, if any dressing is actually better than the others. Tegaderm is a good one as is Duoderm. No ointment is necessary under these and they can stay for several days at a time and the patient can shower with them on. There are also some silver impregnated dressings that may be of benefit, but more expensive and harder to find. As with a burn wound some people advocate the use of Silvadene cream. Silver is both antibacterial and helps with wound healing, but can't say that there are double-blind studies proving it is superior to other agents. Zinc is also touted as promoting wound healing, but as I said above, these biologic dressings don't require any topical applications beneath them. What ever you do, don't send her to a plastic surgeon yet or other surgeon. Surgeons cut. She doesn't need any more injury. Grafting this could be a disaster. I have experience with hyper baric oxygen chambers, but they are hard to find, expensive, often not covered by insurance and require like 40 daily treatments. I'm pretty sure there isn't one close to you, but maybe. However, I've seen patients go through the full course of treatment without any improvement. This is just going to take a long time to heal, frequent intervention for debridement and a lot of hand-holding. I'd be happy to keep consulting through photos as her course progresses.

  6. Prof. Bhushan KumarOctober 21, 2019

    Ecthyma- will now heal of its own. It is sometimes brought about by an insect bite and then inoculation of Staphylococci by scratching.

  7. Comment from Richard Sontheimer, M.D. SLC, Utah: " would agree with those who have made prior comments about this looking like a late-phase brown recluse spider bite reaction. To my eye, the early photos are very reminiscent of an acute brown recluse spider bite reaction. And, a solitary chronic necrotic lesion argues against an autoimmune-mediated vasculopathy such as antiphospholipid antibody syndrome. However, I can understand why with her DVT history you might consider this. I do agree with pursuing an anti-cardiolipin antibody assay.

    At this point, watchful waiting with hydrocolloid bandaging is about the only thing I would consider. I have typically recommended had the patient cover the eschar with an antibacterial ointment such as mupirocin prior to applying a new hydrocolloid dressing to be left in for at lease three days. I agree that aggressive surgical debridement at this point would not be a good idea. Medical debridement of the eschar with topical NexoBrid (bromelain) is an interesting thought. From what I have reviewed, it appears that the FDA has given orphan drug status to this new topical products for debridement of burn eschars. However, I have seen nothing on its use in the debridement of spider bite wounds. I'm sure because of its high proprietary price and non-FDA indication, it would likely not be covered by her insurance."


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