Dermatology: Practical and Conceptual


Image Letter | Dermatol Pract Concept. 2025;15(1):4901 1

Pitted Keratolysis Associated with Cutaneous 
Small-Vessel Vasculitis Resembling Deep Vein 

Thrombosis
Mengyi Zha1, Delaney D. Ding2

1 Yakima Valley Farm Workers Clinic, Yakima, Washington, United States of America

2 University of Florida College of Medicine, Gainesville, Florida, United States of America

Citation: Zha M, Ding DD. Pitted Keratolysis Associated With Cutaneous Small-Vessel Vasculitis Resembling Deep Vein Thrombosis. 
Dermatol Pract Concept. 2025;15(1):4901. DOI: https://doi.org/10.5826/dpc.1501a4901

Accepted: August 29, 2024; Published: January 2025

Copyright: © Zha et al. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 
License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and 
reproduction in any medium, provided the original authors and source are credited.

Funding: None.

Competing Interests: None.

Authorship: All authors have contributed significantly to this publication. 

Corresponding Author: Delaney D. Ding, 1600 SW Archer Road, Gainesville, FL 32610. E-mail: ddd68@cornell.edu 

Case Presentation

A 31-year-old man was referred for a recurrent leg “rash” 

causing pain and swelling. This “rash” recurred four times 

in the preceding two years. Physical exam revealed a limp-

ing patient with a band-like erythematous patch wrapping 

around the right lower leg, swelling, and pain in the right 

calf (Figure 1A). Dermoscopy showed red dots within a 

patchy orange-brown base (Figure 1B) that raised the sus-

picion of cutaneous small-vessel vasculitis (CSVV), which 

was later confirmed by biopsy. However, due to the re-

semblance to deep vein thrombosis (DVT), a stat D-dimer 

was obtained and was negative. The patient denied recent 

illness, but inspection of his feet showed small crater-like 

pits on the plantar surfaces and malodor (Figure 1C). 

Upon further questioning, the patient reported working in 

a wet environment and having had persistent feet malodor 

for two years. Ultraviolet (UV) light revealed coral-red flu-

orescence between the toes grossly (Figure 1D) and in the 

pits dermoscopically  (Figure  1E). A clinical diagnosis of 

pitted keratolysis (PK) was made. Azithromycin 500 mg 

daily for three days resulted in the resolution of both the 

feet and leg rashes. 

Teaching Point

Dermoscopy can improve the diagnostic accuracy of  

CSVV [1] and spare time in the investigation of associated 

conditions such as infections. UV light associated with der-

moscopy techniques can assist in the diagnosis of PK [2]. 

Though previously not reported, our case suggests that un-

treated and persistent PK can be associated with CSVV, which 

can even resemble a DVT. When CSVV is suspected, it is im-

portant to examine the feet with UV light and dermoscopy. 



2 Image Letter | Dermatol Pract Concept. 2025;15(1):4901

References

1. Bakay OSK, Kacar N, Gonulal M, et al. Dermoscopic Fea-

tures of Cutaneous Vasculitis. Dermatol Pract Concept. 2024; 

14(1):e2024051. DOI:10.5826/dpc.1401a51

Figure 1. (A). A band-like erythematous patch wrapping around the right lower leg associated with pain 

and swelling. (B) The dermoscopic view: red dots within a patchy orange-brown base. (C) Crater-like pits 

on the plantar surfaces of foot. (D) UV light revealed coral-red fluorescence between the toes. (E) UV light 

dermoscopy revealed coral-red fluorescence around a pit.

2. Pietkiewicz P, Navarrete-Dechent C, Salwowska N, Cantisani C,  

Goldust M, Errichetti E. Ultraviolet-Induced Fluorescence Der-

matoscopy Reveals Fluorescent Clues in Pitted Keratolysis. 

Dermatol Pract Concept. 2023;13(3):e202342. DOI:10.5826 

/dpc.1303a242