Dermatology: Practical and Conceptual


Dermatology Practical & Conceptual

Image Letter | Dermatol Pract Concept. 2021; 11(4):e2021093 1

Dermoscopy of Green Nail Syndrome:  
The “Green Aurora Sign”

Miguel Dominguez-Santas1, Borja Diaz-Guimaraens1, Juan Jimenez-Cauhe1,  
Ana Suarez-Valle1.

1 Dermatology Department, Ramon y Cajal University Hospital, Madrid, Spain

Citation: Dominguez-Santas M, Diaz-Guimaraens B, Jimenez-Cauhe J, Suarez-Valle A. Dermoscopy of green nail syndrome:  
the “green aurora sign”. Dermatol Pract Concept. 2021; 11(4):e2021093. DOI: https://doi.org/10.5826/dpc.1104a93

Accepted: March 2, 2021; Published: October, 2021

Copyright: ©2021 Dominguez-Santas et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 
License 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: Miguel Dominguez-Santas, MD. Dermatology Department, Ramon y Cajal University Hospital. Carretera 
Colmenar Viejo km 9.100, 28034 Madrid, Spain. Email: miguelds92@hotmail.com

Case Presentation

A 49-year-old woman presented to our dermatology depart-

ment with a 1-year-long history of asymptomatic nail discol-

oration affecting the thumb of her right hand. She referred 

that she was treated with oral fluconazole by her general 

practitioner with no clinical improvement.

Dermatological examination showed dark green discol-

oration of the nail plate (Figure 1A). Dermoscopy of the 

nail plate showed a brighter green discoloration with bluish 

hues (Figure 1B). Dermoscopy of the free edge showed distal 

onycholysis and the presence of the pigment in the ventral 

side of the plate (Figure 1C). The patient in this manuscript 

provided written informed consent to the publication of her 

case details.

Teaching Point

Green nail syndrome is caused by the accumulation of pyocy-

anin that is produced by Pseudomonas aeruginosa bacterium 

[1]. Although it may be confused with onychomycosis, the 

absence of nail bed hyperkeratosis should guide the clinician 

towards the correct diagnosis. Onychomycosis can present the 

aurora borealis sign if dermoscopy is used [2], we therefore 

suggest using the term “Green aurora sign” to differentiate green 

nail syndrome dermoscopy from the one seen in onychomycosis.



2 Image Letter | Dermatol Pract Concept. 2021; 11(4):e2021093

References

1. Maes M, Richert B, de la Brassinne M. Green nail syndrome or 

chloronychia. Rev Med Liege. 2002; 57: 233–235.

2. Piraccini BM, Balestri R, Starace M, Rech G: Nail digital der-

moscopy (onychoscopy) in the diagnosis of onychomycosis. 

J Eur Acad Dermatol Venereol. 2013; 27: 509–513. DOI: 

10.1111/j.1468-3083.2011.04323.x.PMID:22040510.

Figure 1. (A) Dark green discoloration of the nail 

plate. (B) Dermoscopy of the nail plate showed 

a brighter green discoloration with bluish hues. 

(C) Dermoscopy of the free edge showed distal 

onycholysis and the presence of the pigment in 

the ventral side of the plate.