Urticarial Vasculitis secondary to Sarcoptes scabiei

UTSW ID Case Conference 8/13/20 by 1st year fellow Dr. @JohnHan59390335

An elderly patient presented to allergy clinic due to generalized itchy rash for about 1 month. Rash initially started on thighs but then spread to entire body. Lesions last for about 24 hours, then fade

After fading, they leave dark pigmented spots.

PMH: renal cell carcinoma, s/p nephrectomy. Social hx: denies any drugs, no outdoor activities, no other risk factors; wife recently required rehab stay after a hospitalization. Meds: no new medications.

Vital signs stable. General exam unremarkable except skin exam as below.

Skin biopsy taken and showed leukocytoclastic vasculitis. Pt trialed on colchicine, dapsone, and prednisone which showed initial improvement, but then rash relapsed over period of 1 year.

During one relapse, he was seen in dermatology clinic with below exam.

Diagnosed with scabietic urticarial vasculitis! Treated with topical Permethrin and oral Ivermectin and rash completely resolved.

Teaching points:
-Urticarial vasculitis (UV) is an uncommon presentation of scabies with frequently delayed diagnosis (this was reported case number 13).
-Treatment of UV is challenging
-Treatment of the underlying cause generally result in resolution of UV.

The patient’s risk factor for scabies was wife who recently stayed in a rehab/care facility; outbreaks of scabies are very concerning in institutions, schools, military camps, and prisons.
-Presents with intensely itchy skin, detection of even one burrow is pathognomonic

The clinical presentation of scabies in this elderly population differs from the classic
-Bacterial super-infections complicates scabies and can be fatal
-Dementia was identified as a risk factor for scabies so these patients should have a thorough examination

Originally tweeted by Kruti Yagnik (@KrutiYagnikDO) on 13 August, 2020.

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