Sir,

Herein, we present the case of a 72-year-old housewife in Mexico City with a dermatosis on the right thumbnail, showing a very light green to almost blackish colored nail, with areas of xanthonychia, onychoschizia, and onycholysis. Onychoscopy revealed chromonychia, irregular pits, and paronychia in the proximal and lateral periungual folds (Figs. 1a and 1b).

Figure 1: a) Clinical and b) onychoscopic features of Goldman–Fox syndrome.

The condition had been present for six months, following direct trauma during housework. It progressed from the distal to the proximal region, affecting 70% of the nail plate. Despite receiving both topical and systemic antimicrobial treatments, there was no improvement. The patient remained asymptomatic and had no other documented diseases.

Based on these findings, a diagnosis of chloronychia (Goldman–Fox syndrome) was made, and the patient was referred to the laboratory for mycological studies. Direct examination with 10% potassium hydroxide (KOH) revealed yeast clusters. Culture on CHROMagar Candida® medium demonstrated growth of Candida tropicalis and Candida parapsilosis suggestive colonies, which was confirmed by Biomerieux MALDI-TOF MS (Figs. 2a and 2b). A clinical and mycological diagnosis of synchronous onychomycosis caused by two Candida species was established.

Figure 2: a) Yeast clusters and few pseudohyphae (KOH; 40x). b) Identification of strains through colony growth of C. tropicalis and C. parapsilosis on Chromagar culture medium.

Treatment was initiated with 150 mg of oral fluconazole administered once weekly for twelve weeks, followed by the topical application of ciclopiroxolamine lacquer. The clinical progression was satisfactory, with complete resolution of the disease observed during both clinical and dermoscopic follow-up (Figs. 3a and 3b).

Figure 3: Follow-up of a) the clinical and b) dermoscopic improvement of the case after twelve weeks of treatment.

Onychomycosis is a fungal infection of the nail that can affect the matrix, lamina, and folds, with an incidence exceeding 50% of nail diseases [1,2]. It is primarily caused by dermatophytes, non-dermatophytes molds, and yeasts, which mainly affect the fingernails [1,3,4]. Candida infections are particularly common in immunosuppressed individuals, and their behavior is influenced by various factors, including environmental conditions, cosmetics, chronic trauma, constant exposure to humidity, housework, advanced age and the patient’s immune status [1–3,5].

Green nail syndrome (chloronychia), also known as Goldman–Fox syndrome, was first described in 1944. It is characterized by a sallow-greenish discoloration of the nail plate, which can be either partial or total. This condition is primarily associated with bacterial infection caused by Pseudomonas aeruginosa, but it can also be linked to opportunistic fungi such as Candida albicans, C. parapsilosis, and C. tropicalis. Clinical manifestations include the triad of chloronychia (ranging from yellowish-green to greenish-black), proximal paronychia, and laterodistal onycholysis [4].

Candida infections typically present with onychodystrophy, hyperkeratosis, onycholysis, paronychia, transverse ridges, and chromonychia, exhibiting whitish, yellowish, or greenish hues. These overlapping signs can complicate clinical differentiation, particularly in the absence of targeted studies. Therefore, a comprehensive clinical evaluation, onychoscopy, and mycological studies are essential for accurate diagnosis [2–4].

In pathogenesis, C. albicans is characterized by its high activity of exoenzymes, including phospholipase, esterase, and β-hemolysin, which facilitate nail invasion. In contrast, C. parapsilosis generally exhibits lower enzymatic activity, although certain strains produce serine peptidase with keratolytic activity [4]. C. parapsilosis as a cause of onychomycosis has increased in recent years, so it is considered an emerging species and may develop resistance, particularly to triazoles [5].

The simultaneous isolation of two or more Candida species from nails is uncommon but clinically significant, as pathogenic synergy between them is possible [1]. It is crucial to evaluate the patient’s environment and habits, particularly in cases involving the use of artificial nails or frequent exposure to detergents and moisture [1,2,6,7].

Candida infections typically respond well to azole antifungals [1,5,7]. The addition of ciclopirox or amorolfine lacquers enhances the efficacy of systemic therapy, particularly in cases with onycholysis [1].

In conclusion, the simultaneous isolation of Candida tropicalis and Candida parapsilosis in an immunocompetent patient represents an uncommon finding in the literature. This highlights the complexity of candidal onychomycoses and suggests the potential for synergistic interactions between species.

REFERENCES

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2.Alvarado A, Hernández-Álvarez G, Fernández R, Arenas R. Onicomicosis por Candida en las uñas de las manos. Dermatol Rev Mex. 2014;58:323-30.

3.Sierra-Maeda KY, Segundo-López LD, Vega DC, Juárez-Durán ER, Arenas R. Síndrome de las uñas verdes:una revisión. Dermatol Cosmet Med Quirurg. 2022;20:78-85.

4.Jimenez B, Rivero-Bermúdez MD, Marte-Colina IJ, Vivas-Toro SC. Goldman–Fox syndrome associated with yeast. Rev Asoc Colomb Dermatol Cir Dermatol. 2024;32:64-9.

5.Tirado-Sánchez A, Bonifaz A. Candida onychomycosis:An old problem in modern times. Curr Fungal Infect Rep. 2020;14:209-16.

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7.Ge G, Yang Z, Li D, Sybren de Hoog G, Shi D. Onychomycosis with greenish-black discolorations and recurrent onycholysis caused by Candida parapsilosis. Med Mycol Case Rep. 2019;24:48-50.