ARTICLE
Tinea capitis by Trichophyton schöenleinii
The direct microscopic examination of the scrapings and hair, with lactophenol
- blue, showed septate hyaline hyphae and arthrospores with an endothrix
parasitism (Fig. 2).
Sabouraud dextrose agar with antibiotics and mycobiotic cultures were
incubated at 25º C and 37º C. The cultures showed slow growing
waxy colonies with irregular borders that submerged into the agar. The
surface of the colonies, at first white, became cream coloured and the
reverse was non-pigmented (Fig. 3).
This dermatophyte grew equally at room temperature and at 37º C.
The urease test was negative and growth was not enhanced on media enriched
with vitamins or aminoacids. Irregular and multiple branched hyphae with
broadened tips, or antlerlike structures also known as favic chandeliers
were the characteristic features seen (Fig. 4). Chlamydospores
were common in older cultures. Neither microconidia nor macroconidia were
seen.
A diagnosis of tinea capitis by Trichophyton schöenleinii
was made.
She was treated with 15 mg/kg/day of oral micronized griseofulvin (375
mg once a day) and ketoconazole shampoo (once a day) for twelve weeks.
All the household members (a total of ten children and one adult) and
our patient's sister, who was visiting her frequently at that time, were
screened for the presence of hair and scaling lesions and fluorescence.
A total of six samples were collected from the fluorescence positive scalps.
We detected T. schöenleinii only in our patient's sister.
Nevertheless, all the children were treated with ketoconazole shampoo
(once a day) and her sister was additionally prescribed oral griseofulvin.
Patients were rechecked and cultures obtained, and the child was clinically
and mycologically cured. We do not know what happened to her sister since
we lost contact.
T. schöenleinii is an important anthropophilic dermatophyte
that causes Tinea favosa, a rare and chronic disease characterised by
the presence of yellowish, cup-shaped crusts called scutula, on the scalp
and glabrous skin [1], and severe alopecia. Besides this classic clinical
type there are erythematous follicular forms, without alopecia, similar
to seborrheic dermatitis, psoriasis or tinea amiantacea [2, 3]. Because
of its non-inflammatory appearance, the disorder may persist for years
before it is diagnosed [2].
The peculiar type of hair invasion (endothrix favic) contributes to
the chronic course of the favus, which may persist in adult life [4].
Endothrix infections are more likely to result in outbreaks among family
members or intimate friends [3]. T. schöenleinii can be transmitted
from person to person by sharing towels or clothing [5].
A recent study has revealed that symptomatic children may not be the
source of infection of other children [6]. However, it showed that a high
percentage of symptom-free adult carriers at home could act as reservoirs
of infection [4] and were responsible for the spread and persistence of
scalp ringworm in the community [7].
The question of whether asymptomatic carriers should be treated with
oral antifungals or antiseborrheic shampoos remains [8]. However, there
is a slight risk of adverse reactions from oral griseofulvin administered
for 4-6 weeks [4]; the regular use of a shampoo is an appealing solution
for controlling the carrier state, particularly in closed institutions.
Unfortunately only one controlled study has evaluated treatment options
for the carrier state [2, 4, 7, 8].
Although the favus occurred worldwide in the past it is now limited
to some endemic regions, probably due to the great improvement of socio-economic
conditions [9, 10]. During the past decade, there have been some cases
confined to Germany [11], West Iran [12], Jordan [13] and Brazil [14].
Our patient presented a seborrheic-like scaling, without alopecia, resistant
to the usual treatment and not suggestive of tinea capitis. We emphasise
the importance of microbiological study in such cases.
Her sister was presumably the source of the infection, since the household
members who had a positive fluorescence, were not infected and the others
had apparently healthy scalps.
In spite of being a rare agent of tinea in Portugal nowadays, T.
schöenleinii exists sporadically in endemic areas, which also
happens in other countries [9, 10]. As we lost contact with our patient's
sister we presume the source may not be totally eradicated.
Article accepted on 30/1/01
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