An unusual case of onychomycosis due to

Fonsecaea pedrosoi

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Case Report

An unusual case of onychomycosis due toFonsecaea pedrosoi

B. Shweta a,*, A. Archana b, G. Nupur a

a Specialist, Microbiologist, National Centre for Disease Control, 22, Sham Nath Marg, Delhi 110054, Indiab Public Health Specialist, National Centre for Disease Control, 22, Sham Nath Marg, Delhi 110054, India

a r t i c l e i n f o

Article history:

Received 7 November 2014

Accepted 7 November 2014

Available online xxx

Keywords:

Onychomycosis

Dematiaceous

Fonsecaea pedrosoi

* Corresponding author.E-mail address: aimcnicd@gmail.com (B.

Please cite this article in press as: Shweta(2014), http://dx.doi.org/10.1016/j.apme.2

http://dx.doi.org/10.1016/j.apme.2014.11.0030976-0016/Copyright © 2014, Indraprastha M

a b s t r a c t

Onychomycosis is usually caused by dermatophytes, but some nondermatophytic molds

and yeasts are also associated with invasion of nails. Here is a report of a case of distal and

lateral subungual onychomycosis (DLSO) caused by Fonsecaea pedrosoi where it acts as

primary agent of nail infection.

Case report: A 30-year-old male presented with a 1-year history of brownish-black discol-

oration with hyperkeratosis on the finger and toenails. Scrapings were collected for smears

and culture.

Dematiaceous hyphae were seen on wet mounts of the scrapings and dark pigmented

colonies grew repetitively on the culture media; all colonies were identical, and were

subsequently identified as F. pedrosoi.

In humid tropical regions F. pedrosoi is one of the primary causes of human chronic

cutaneous mycosis, chromoblastomycosis. The case presented had certain unusual fea-

tures. The disease was caused by an unusual fungus (Fonsecaea), occurred at an unusual

site (nail) and in an immunocompetent individual.

Combination of antifungal medications may provide the best option for cure in

onychomycosis.

Copyright © 2014, Indraprastha Medical Corporation Ltd. All rights reserved.

1. Introduction

Onychomycoses constitutes a frequent fungal infections seen

in dermatological practice worldwide. The clinical picture is

very variable, but that in general is characterized by nail ar-

chitecture alterations, such as changes in color, thickness,

onycholysis and onycodistrophy. In most cases they are

caused by species of filamentous fungi like the dermatophytes

or yeasts of the genus Candida. However, in a small fraction of

the cases, the etiologic agents comprise nondermatophyte

filamentous fungi, belong to several genera and species.1

Shweta).

B, et al., An unusual cas014.11.003

edical Corporation Ltd. A

Nondermatophyte onychomycosis account for 2%e12%

of all nail fungal infections and can be caused by a wide

range of fungi, including Scopulariopsis brevicaulis,

Penicillium spp., Aspergillus spp., Fusarium spp., Ulocla-

dium spp., Acremonium spp., Alternaria spp, Cladosporium

spp., Paecilomyces spp., Curvularia spp., Chaetomium

spp.,Scytalidium spp and Trichoderma spp.2e5 The preva-

lence of nondermatophyte onychomycosis varies widely,

according to geographical location or the climate, but it is

more frequent in hot and humid tropical areas. Often they

are considered simple contaminants or secondary patho-

gens, invading nails previously damaged by trauma or

e of onychomycosis due to Fonsecaea pedrosoi, Apollo Medicine

ll rights reserved.

a p o l l o m e d i c i n e x x x ( 2 0 1 4 ) 1e32

disease, although in some cases they actually act as primary

pathogens.1

Dematiceous fungi are the etiological agents of phaeohy-

phomycosis and are now increasingly being recognized as

causing disease in humans specially in immunocompromised

patients.6 Fonsecaea pedrosoi, a dematiceous fungi, is the

commonest causative agent of chromoblastomycosis a

chronic mycotic cutaneous and subcutaneous skin infection,

which primarily occurs in humid tropical regions.7 Till now

only one case of nail infection i.e. of longitudinal melano-

nychia secondary to chromoblastomycosis due to F. pedrosoi

has been reported.8

Here, we report a case of distal and lateral subungual ony-

chomycosis (DLSO) caused by F. pedrosoi where it acts as pri-

mary agent of nail infection. The objective of this study was to

present a case of onychomycosis associated to thedematiceous

fungi F. pedrosoi in a reference hospital in new Delhi, India.

Aspects of fungal pathogenesis, as well as the epidemio-

logical characteristics and laboratory diagnosis, are discussed

below.

2. Case report

A 30-year-old male presented with a 1-year history of

brownish-black discolorationwith hyperkeratosis on the finger

and toenails. There was no history of other symptoms except

for finger and toenail dystrophy. Dermatological examination

revealed theDLSOon the right fingernails (1st and 5th), toenails

(1st, 2nd, 4th and 5th) and left toenails (1st and 5th). Complete

blood count, peripheral blood smear, urinalysis, liver and renal

function tests and stool examination were within normal

limits for both patients. Venereal disease research laboratory

test and serological tests for hepatitis virus and human im-

munodeficiency virus were also negative. Chest X-ray and

electrocardiogram were unremarkable. In mycological exami-

nation, fungal elementswere observed in potassiumhydroxide

(KOH) preparations from the both toenail and fingernail lesions

of the patient. Nail specimens were cultured on two slants of

Sabouraud's dextrose agar (SDA) without cycloheximide at

25 �C for 2 weeks, which yielded several identical appearing

colonies. The moderately slow-growing colonies were initially

white then turned spreading, lanose and olivaceous-green

colonies with a blackish reverse. We performed repeated

(three) cultures taken from nail plates at 2-week intervals; all

yielded similar findings. When the slide cultures of fungal

colonies were stained with lactophenol cotton blue, it showed

the two typical morphologic forms: i) light brown co-

nidiophores, profusely branched with cylindrical, intercalary

or terminal conidiogenous cells with clusters of prominent

denticles and ii) the Phialophora synanamorph, characterized by

ampulliform, darker phialides with conspicuous funnel-

shaped collarettes. The conidia were smooth-walled, clavate,

pale olivaceous and measured 3.5e5 � 1.5e2 mm.

3. Discussion

Dematiaceous fungi, including F. pedrosoi, are a group of het-

erogeneous ubiquitous fungi known to cause

Please cite this article in press as: Shweta B, et al., An unusual cas(2014), http://dx.doi.org/10.1016/j.apme.2014.11.003

phaeohyphomycosis, a spectrum of disease ranging from su-

perficial to deep-seated infections.6 The distinguishing char-

acteristic common to these fungi is the presence ofmelanin in

their cell wall, which is also believed to be a virulence factor.6

The genus Fonsecaea is not an established cause of ony-

chomycosis. To the best of the present authors' knowledge,

only one case of longitudinal melanonychia secondary to

chromoblastomycosis due to F. pedrosoi has been reported.8

However no case where F. pedrosoi acts as a primary cause of

onychomycosis has been reported till date. Infection is

through traumatic inoculation into the skin with infected

plant material. These infections can be classified in four

clinical forms: superficial, cutaneous, subcutaneous and sys-

temic. In category cutaneous includes the onychomycosis.9

Onychomycosis caused by dematiceous fungi is unusual.

These organisms are characterized by brownish-black

pigmentation of the host cells and culture of their colonies

blackish brown. So, due to this natural pigmentation of their

septate hyphae, can simulate melanonychia caused by mel-

anocytic lesions such as melanoma of the nail apparatus.9

From the clinical view point, the lesions caused by infect-

ing species of the genus Fonsecaea were very similar to those

caused by dermatophytes. The affected nails displayed dis-

trophy and onycholysis, usually with alterations of the distal

subungueal region.10

Regarding the laboratory diagnosis of Fonsecaea infections,

as in other nondermatophyte fungi infections, it is always

necessary to confirm if the fungus is the real etiologic agent of

the onychomycosis, by the repetition of the examswith a new

collected sample.10

The case presented had certain unusual features. The

disease was caused by an unusual fungus (Fonseca0e00 a),

occurred at an unusual site (nail) and in an immunocompe-

tent individual.

Treatment of the mycosis caused by this agent is unre-

warding not only because of the scarcity of effective anti-

fungals but also due to the need for prolonged periods of

treatment, which in some reports has required prolonged

therapeutic regimens of up to 2 years to obtain a mycologic

cure. Several studies have indicated, by minimal inhibitory

concentration (MIC)values, that itraconazole presents no

resistance to F. pedrosoi.7 Although in vitro susceptibility

testing does not reliably predict in vivo efficacy for fungi, and

MICs can not be used as strict guidelines for therapy, the

possibility of performing in vitro tests should be considered.

In that way, one may avoid ineffective, costly and a pro-

longed course of treatment. In view of the lack of suscepti-

bility of this agent to the current antimycotic drugs, it may

be wiser to seriously consider the possibility of combining

the best available drugs in order to obtain a synergistic

effect.7

Therefore, a high index of suspicion in both treating clini-

cians andmicrobiologists is necessary for the diagnosis of this

entity, the reasons being the rarity of the disorder and the

need for prolonged treatment, once identified. Confirmation

of the specific pathogen (such as F. pedrosoi, in this case) would

lead to not only initiation of the proper therapy but also pre-

vention of premature discontinuation of therapy that would

potentially deny the benefit of getting cured to the rare patient

who may be unfortunate enough to suffer from this disease.

e of onychomycosis due to Fonsecaea pedrosoi, ApolloMedicine

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Other importance of this case is the differential diagnosis

of cause of melanonychia, especially with melanomas of the

nail apparatus, as this rare type of cancer has bleak prognosis.

In conclusion, clinicians must appreciate that the Non-

dermatophyte fungi should no longer be disregarded as pure

contaminants and choose optimal antifungal agents

accordingly.

Conflicts of interest

All authors have none to declare.

r e f e r e n c e s

1. Rell LN, Hasse J, Galindo CC, et al. Onychomycosis byScytalidium dimidiatum: report of two cases in SantaCatarina, Brazil. Rev Int Med Trop. 2005;47:351e353.

2. Naidu J. Growing incidence of cutaneous and ungulainfections by non-dermatophyte fungi at Jabalpur(M.P.).Indian J Pathol Microbiol. 1993;36:113e118.

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3. Hilmioglu-Polat S, Metin DY, Inci R, et al. Non-dermatophytic molds as agents of onychomycosis inIzmir, Turkey e a prospective study. Mycopathologia.2005;160:125e128.

4. King DM, Lee MK, Suh MK, et al. Onychomycosis caused byChaetomium globusum. Ann Dermatol. 2013;25:232e236.

5. Moreno G, Arenas R. Other fungi causing onychomycosis. ClinDermatol. 2010;28:160e163.

6. Singh N, Agarwal R, Gupta D, et al. An unusual case ofmediastinal mass due to Fonsecaea pedrosoi. Eur Respir J.2006;28:662e664.

7. Lima ALH, Guarro J, Freitad D, et al. Clinical treatment ofcorneal infections due to Fonsecaea pedrosoi e case Report.Arq Bras Oftalmol. 2005;68:270e272.

8. Sarti HM, Vege-Memije ME, Dominguez-Cherit, et al.Longitudnal melanonychia secondary tochromoblastomycosis due to Fonsecaea pedrosoi. Int JDermatol. 2008;47:764e765.

9. Carvalho Vl, Mendonca IM, Val A, et al. Melanonychia : thepurpose of a case simulating. Dermatol Online J. 2010;16.

10. Gupta AK, Ryder JE, Summerbell RC. The diagnosis ofnondermatophyte mold onychomycosis. Int J Dermatol.2003;42:272e273, 2.

e of onychomycosis due to Fonsecaea pedrosoi, Apollo Medicine

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