Nail Changes in Secondary Syphilis: A Report of 3 Cases and Review of Literature

Abstract

Introduction

Nail changes have been described in syphilis in all stages. However, they can be subtle and easy to miss. At the same time, they are valuable indicators towards underlying pathology as nail is a useful “window to systemic disease.” Onychoscopic features of nail syphilis have not been described in detail.

Case Report

We describe 3 patients (n = 60 nails) with secondary syphilis with involvement of 29/60 (48.3%) nails. Most common clinical nail findings were onychorrhexis (13, 37%), followed by distal onycholysis (10, 28%). Other findings included subungual hyperkeratosis, onychomadesis, Beau’s lines, nail plate atrophy, paronychia, and periungual ulceration. Onychoscopic involvement was seen in 32/60 (53.3%) nails. Features observed on onychoscopy were onychorrhexis (13/60) and distal onycholysis (including erosive onycholysis) (12/60). Distinctive features on onychoscopy included alternate white and red lines, longitudinal erythematous bands, and ulcerative onycholysis.

Conclusion

Nail involvement in syphilis, particularly the onychoscopic findings, has been under-reported. Varying terminologies have been used over the years as per the literature review. We propose that nail syphilis is best classified based on the site of involvement within the nail unit. Onychoscopy aids the detection of changes which may be missed on clinical examination.

Established Facts

• Nail changes in syphilis are described as onychial and perionychial changes.

• They are more often reported in secondary syphilis.

Novel Insights

• Nail changes in syphilis affect all parts of the nail unit and are best classified based on the sites of involvement as nail matrix, nail bed, and nail fold syphilis.

• Onychoscopy is helpful to detect nail changes in patients with syphilis even when clinically not apparent.

Introduction

Syphilis, commonly known as the “great imitator,” is a chronic systemic infection caused by the spirochete Treponema pallidum subs. pallidum. There is a wide variation in the prevalence rates across different age groups in various countries including India. Nevertheless, there has been a resurgence of new cases in the last decade. Various factors contributing to this include the human immunodeficiency virus (HIV) epidemic, rising global travel, a higher incidence of men having sex with men, common online relationships with casual sex, and also an increased awareness, leading to increased diagnosis [1]. Nail involvement in syphilis is reportedly uncommon, but reported across all stages of syphilis, that is, primary, secondary, and tertiary syphilis. However, it is traditionally under-recognised and under-reported. The limited reports available in literature have used varying terminologies. There have been no systematic studies focussing on nail syphilis. Onychoscopy is a non-invasive means to identify nail features which may not be visible on clinical examination alone. However, there has been a lack of reports on the onychoscopic features of the disease.

We report a series of 3 patients of skin of colour, with secondary syphilis who were found to have nail changes. A prospective observational evaluation was done including serological tests (including Venereal Disease Research Laboratory [VDRL], treponema pallidum haemagglutination [TPHA], hepatitis B, anti-hepatitis C virus antibody, HIV) with a thorough clinical and onychoscopic examination of all nails. The clinical and onychoscopic findings were documented and categorised based on the site of involvement within the nail. The literature was also reviewed using the search strategy “Nail AND Syphilis” on PubMed. The relevant English language reports were retrieved and analysed. A narrative review is presented.

Case Details

Case 1

A 25-year-old unmarried, heterosexual male presented with multiple, asymptomatic pigmented lesions over upper back, soles, and genitalia for 4 months. He also complained of patchy hair loss and oral lesions. He had toenail thickening and discoloration for the past 2 years, but complained of some tenderness over the past 2 months. He gave history of a single paid contact 6 months ago with a commercial sexual worker, unprotected, peno-vaginal, and not under the influence of alcohol.

On examination, he had stable vitals and no pallor, lymphadenopathy, or oedema. Multiple copper-coloured, scaly, papulo-squamous plaques with collarette of scales were identified over the trunk, both soles (shown in Fig. 1a), nail folds (shown in Fig. 1b), and penile skin. There was a single well-defined, asymptomatic, whitish mucous patch present over the buccal mucosa. Finger and toenails showed onychorrhexis, distal onycholysis, and Beau’s lines. Pre-existing thickening and subungual hyperkeratosis involving toenails were suggestive of onychomycosis (shown in Fig. 1b). Onychoscopy revealed distal onycholysis, subungual hyperkeratosis, and Beau’s lines (shown in Fig. 1c). However, direct microscopy and culture of nail clippings were negative for bacterial or fungal growth. The patient denied any nail biopsy. Serological tests showed a VDRL titre of 1:32, TPHA-positive, HIV, HBsAg, and anti-HCV-negative. Based on the clinical findings and serological reports, a diagnosis of secondary syphilis with nail involvement was made. Treatment with benzathine penicillin led to improvement in the skin lesions and resolution of nail changes over further 6 months of follow-up, though thickening persisted.

Fig. 1.

a Case 1 showing multiple copper-coloured, scaly plaques with collarette of scales involving the feet. b Toe nails showing distal discoloration, distal onycholysis, and SUH with Beau’s lines. Syphilitic plaque with hyperpigmentation can be seen involving the PNF and digital skin. c Onychoscopy showing brown-yellow discoloration of distal nail (suggestive of onychomycosis) with lamellar separation of the nail plate (onychoschizia) and Beau’s lines. PNF, proximal nail fold; SUH, subungual hyperkeratosis.

Case 2

A 22-year-old unmarried homosexual male presented with multiple lesions over trunk, genitalia, face, and nape of neck for 6 months. There was history of multiple sexual contacts with multiple partners. The patient was thin-built with stable vitals. There were multiple asymptomatic, copper-coloured papules and plaques over the trunk and genitalia (shown in Fig. 2a, b). Few tender, ulcerated plaques were seen over the beard area and nape of neck. Nail examination showed periungual ulceration and paronychia involving right 4th fingernail (shown in Fig. 2c) and distal erosive onycholysis in the left digit. Onychoscopy showed distal onycholysis (erosive), loss of cuticle, paronychia, and periungual ulceration (shown in Fig. 2d). Serology showed VDRL-1:8, TPHA-positive, HIV-positive, HBsAg, and anti-HCV-negative. A diagnosis of secondary syphilis with nail involvement, with HIV, was made. The patient was treated with single dose injection benzathine penicillin 2.4 million IU which led to improvement in skin changes and healing of ulceration over further 3 months of follow-up.

Fig. 2.

a Case 2 showing multiple copper-coloured, papules and plaques involving the trunk. b Multiple asymptomatic, condyloma lata involving the scrotum and penile shaft. c Nail examination showing periungual ulceration, paronychia of right ring finger, and distal ulceration (erosive onycholysis) of the left index finger. d Onychoscopy showing loss of cuticle, ulcerative paronychia, and erythematous patch involving the nail bed.

Case 3

A 28-year-old unmarried homosexual male presented with brittle nails, nail splitting, and erythematous discoloration of the nail plates for 2 months. There was history of multiple protected as well as unprotected sexual encounters over the past 1 year. He denied history of similar lesions in any of the sexual partners. On examination, mucous patch was seen with generalised lymphadenopathy (shown in Fig. 3a). Nail examination showed marked thinning, with nail bed erythema, and onychorrhexis (shown in Fig. 3b, c). Onychoscopy showed loss of cuticle, onychorrhexis, alternate white and red bands, longitudinal red bands (shown in Fig. 3d). Serology showed VDRL titre of 1:16, TPHA-positive, HIV, HBsAg, and HCV-negative. A diagnosis of secondary syphilis with nail involvement was made. Treatment with benzathine penicillin led to resolution of mucosal lesion, though the nail thinning persisted. The patient was lost to follow-up.

Fig. 3.

a Case 3 showing a single well-defined, asymptomatic, whitish mucous patch over mucosal aspect of the lower lip. b Nail examination showing apparent leukonychia, marked nail plate thinning, and onychorrhexis. Longitudinal erythematous bands can be seen. c Similar changes in the other fingernails. One nail shows a subungual hematoma which was post-trauma. d Onychoscopy showing loss of cuticle, onychorrhexis, onychoschizia, nail plate thinning, alternating white and red bands, and longitudinal erythronychia. Distally placed haemorrhages can be seen.

The clinical and onychoscopic features of nail changes in these 3 patients with secondary syphilis are summarised in Table 1. Onychoscopy revealed 32 (53.3%) nails involved as compared to clinically visible changes in 29 (48.3%) nails (p > 0.05).

Table 1.

Clinical and onychoscopic nail changes seen in patients with secondary syphilis (n = 60 nails)

Features	Clinical changes, n (%)	Onychoscopic changes, n (%)
Onychorrhexis	13 (43.3)	13 (43.3)
Beau’s lines	1 (3.3)	1 (3.3)
Distal onycholysis	10 (33.3)	12 (40)
Alternate white and red lines	0 (0)	2 (6.6)
Longitudinal erythematous bands	0 (0)	4 (13.2)
Erosive onycholysis	1 (3.3)	2 (6.6)
Splinter haemorrhage	0 (0)	1 (3.3)
Paronychia	2 (6.6)	2 (6.6)

Discussion

We report 3 patients with secondary syphilis with significant nail changes. On reviewing the literature, it was seen that nail involvement in syphilis, although uncommonly reported, has been well established. It has been reported across all stages of syphilis, though most reports refer to secondary or congenital syphilis. This is not surprising keeping in mind the systemic nature of the disease in these stages.

Varying terminologies have been used for nail syphilis [2–15] including syphilitic onychia [2, 3], onychia craquele of Fournier [2], syphilitic paronychia ulcerosa [4], onychia sicca syphilitica [10], nail plate syphilis [6], syphilitic nail dystrophy [14], or syphilitic onychopathy [15] (Table 2). This has probably been the reason for ongoing confusion in literature. As seen in the cases reported, syphilis can affect all parts of the nail unit, including nail matrix (producing nail plate changes), nail bed (mostly vascular changes), and nail fold (mostly ulcerative changes). Based on our findings, we propose a scheme of classification of nail syphilis to ease communication and reporting of future cases (Table 3). Nail plate changes have been termed as syphilitic onychia and result due to the inflammation of the nail matrix. These include brittleness, pitting, elkonyxis, Beau’s lines, onychomadesis, onychoptosis, and nail loss or anonychia. Nail fold changes occur due to periungual and subungual inflammation, and have been termed as syphilitic paronychia. Nail bed changes, seen as onycholysis and nail bed erythema, reflect the vascular nature of the nail bed. Based on our findings and the review of literature, it can be said that nail fold syphilis is the commonest presentation of nail syphilis. This could present as paronychia, or even onycholysis (due to involvement of distal nail fold or of nail bed). Nail bed syphilis may also be fairly common, but is often underdiagnosed due to its asymptomatic nature, and the need for onychoscopy to pick up subtle nail bed changes.

Table 2.

Nail changes in syphilis as reported in literature

S. No.	Author, year	Design	Sample size	Age/sex	Stage of syphilis	Nails involved, n	Terminology used	Nail features described	Cutaneous features described
1	Cormia et al. [2] (1938)	Case report	1	41/M	Secondary	3	Syphilitic onychia, onychia craquele of Fournier	Longitudinal striations, onychorrhexis, Beau’s lines, proximal swelling, and mega-lunula	Palmo-plantar papular eruption, psoriasiform lesions on elbow
2	Waugh et al. [3] (1972)	Case report	3	33/M, 23/F, 75 d	Secondary, secondary, congenital	Not mentioned	Syphilitic onychia	Onycholysis	33/M – psoriasiform plaques on scalp, erythematous papulosquamous lesions on body, buccal ulceration, circinate balanoposthitis, anal condyloma lata
									23/F – generalised maculopapular rash, generalised lymphadenopathy 75 d/I – catarrhal nasal discharge
3	Kingsbury et al. [4] (1972)	Case report	1	40/F	Secondary	8	Syphilitic paronychia ulcerosa	Painful paronychia with seropurulent discharge, onychomadesis, dirty yellow and thickened nail beds	Palmo-plantar papulosquamous lesions
4	Oh et al. [5] (2012)	Case report	1	20/M	Secondary	1	Nail dystrophy	Scaly exfoliated patch with erythematous swelling, onychodystrophy, and mild tenderness	Multiple erythematous, broad eroded surface papules, and macules on scrotum
5	Bittencourt et al. [6] (2015)	Case report	1	32/M	Secondary	1	Nail plate syphilis	Periungual erythema, SUH, onychodystrophy of toenails	Palmo-plantar papulosquamous lesions
6	Di Biagio et al. [7] (2016)	Case report	1	41/M	Secondary?	1	–	Onychomadesis, onycholysis	Maculopapular rash, anal condyloma lata, alopecia, lymphadenopathy
					Late latent?
					With HIV
7	Noriega et al. [8] (2017)	Case report	1	52/M	Secondary	1	–	Erythematous scaly plaque involving lateral nail fold and hyponychium	Erythematous scaly plaque on leg
8	Fusta et al. [9] (2017)	Case report	1	36/M	Secondary	10	–	Beau’s lines, distal amber discoloration, onychomadesis	Erythematous scaly plaques over palms and soles
					With HIV
9	Gabrielli et al. [10] (2018)	Case report	1	37/M	Secondary	10	Onychia sicca syphilitica, non-primary nail plate syphilis	Well-demarcated, purplish, opaque, rough, vertically ridged plaques over PNF of fingernails	Light-coloured macular rash, sparing palms and soles, maculopapular lesions over volar aspects of forearms
10	Leung et al. [11] (2018)	Case report	1	2 weeks/I	Congenital	20	–	Onychauxis of fingernails and toenails	Diffuse erythematous keratoderma of palms and soles, with fissures and desquamation, linear scaly fissures at angles of mouth
11	Al-Awwad et al. [12] (2020)	Case report	1	38/M	Neurosyphilis	10	Syphilitic onychia	Onychoptosis persistent for 3 months, nail bed syphilis	Subacute bilateral retrobulbar optic neuritis with vision loss
12	Marcantonio et al. [13] (2021)	Case report	1	28/M	Primary	2	Ulcerative paronychia	Painful inflammed nodules on the tip of digits, persistent primary chancre	–
13	Dumlao and Wu [14] (2024)	Case report	2	30/M, 35/M	Secondary	10, 5	Syphilitic nail dystrophy	1. PNF swelling, thick yellow haemorrhagic crusts, brittle and thinned out nail plates	1. Erythematous plaques with hyperpigmented patches
								2. Pitting, onycholysis, salmon patches, central groove resembling koilonychia or onychomadesis, paronychia, and onychomadesis	2. Thick scaling on scalp, erythematous macules, and patches on face, inguinal area, scrotal area
14	Aggarwal and Singal [15] (2025)	Case report	1	68/M	Secondary	2	Syphilitic onychopathy	PNF swelling, crusted erosion, peripheral scaling, ragged cuticle	Palmo-plantar papulosquamous lesions, generalised crusted lesions, condyloma lata

M, male; F, female; I, infant; d, days; SUH, subungual hyperkeratosis; PNF, proximal nail fold.

Table 3.

Summary of nail findings reported in syphilis with a proposed classification scheme based on the site of involvement

Nail matrix/nail plate changes (syphilitic onychia)	Nail bed changes	Nail fold changes (syphilitic paronychia)
Onychorrhexis, longitudinal striations	Onycholysis – distal onycholysis, erosive onycholysis	Primary chancre
Brittleness, distal splitting, thinning	Splinter haemorrhages	Painful paronychia/tenderness
Fissuring	Salmon patches	Seropurulent discharge and haemorrhagic crusting
Pitting, elkonyxis	Subungual hyperkeratosis	Periungual erythema
Mega-lunula	Alternating red and white bands	Proximal nail fold swelling
Beau’s lines	Longitudinal erythronychia	Ragged cuticle, loss of cuticle
Onychauxis	Nail bed thickening and discoloration	Periungual scaling
Onychomadesis	Distal amber discoloration	Painful inflamed nodules on the tip of digits
Nail loss, anonychia	Onychoptosis – persistent and recurrent over months	Well-demarcated, erythematous/purplish, scaly plaques over nail folds
Central groove, resembling koilonychia	​	​

Onychoscopy has evolved as a valuable adjunct to clinical examination of nails. It has been shown to enhance visualisation of nail changes in many nail disorders, over and above those visible to the naked eye. The same was reflected in our patients. Till date, only one previous report has described the onychoscopic features of nail syphilis [15]. Our study found nail plate changes to be more common as compared to nail fold changes, with onychorrhexis being the most common finding. However, the difference was not statistically significant. Moreover, features like alternate white and red lines, ulcerative onycholysis, and longitudinal erythematous bands were exclusively seen on onychoscopy. More reports on onychoscopic evaluation of nail syphilis can help confirm our findings.

Conclusion

Nail changes in syphilis, especially secondary syphilis, should be actively looked for. Use of a standard terminology for nail syphilis, incorporating the spectrum of changes seen, can improve reporting of these cases as they are currently under-recognised and under-reported. Onychoscopy can aid the detection of changes which may be missed on clinical examination. However, these are just preliminary findings and larger studies across various stages of syphilis can validate our findings.

Statement of Ethics

This retrospective review of patient data did not require ethical approval in accordance with local/national guidelines. Written informed consent was obtained from participants to participate in the study and for publication of the details of their medical case and any accompanying images. The CARE Checklist completed by the authors for this case report is available at https://doi.org/10.1159/000546719.

Conflict of Interest Statement

The authors have no conflicts of interest to declare. Dr Chander Grover serves on the Editorial Board of Skin Appendage Disorders.

Funding Sources

None of the authors report any form of support and financial involvement. There are no nonfinancial relationships (personal, political, or professional) that may potentially influence the writing of the manuscript. Dr. Chander Grover is a member of the Editorial Board of Skin Appendage Disorders.

Author Contributions

C.G. diagnosed the patient, did the literature review, and shall act as guarantor. S.A. prepared the first draft of manuscript. C.G. and S.A. contributed equally to the concept, design, definition of intellectual content, data acquisition, and data analysis. A.S. helped in patient management and preparation of draft. All authors did manuscript editing and review.

Funding Statement

None of the authors report any form of support and financial involvement. There are no nonfinancial relationships (personal, political, or professional) that may potentially influence the writing of the manuscript. Dr. Chander Grover is a member of the Editorial Board of Skin Appendage Disorders.

Data Availability Statement

All data generated or analysed during this study are included in this article. Further enquiries can be directed to the corresponding author.