Download Fungal and yeast infection of skin, hair and nails

Fungal and yeast infection
of skin, hair and nails
Forum
Dermatology
The choice of treatment for a fungal or yeast infection depends on the
probable organism and the extent of the infection, writes David Buckley
Picture 1. Tinea pedis sometimes causes an allergic (‘id’) reaction that
causes pompholyx (blistering eczema) on the soles of the feet
Picture 2. Onychogryphosis (above) can often be confused with tinea
unguium
Some fungal infections of the skin are obvious, can be
diagnosed clinically and treated empirically without having
to take samples for the lab (see Table 1). A good example
is an annular rash with raised, red, scaly borders and fading
centres on the arm of a farmer. This is most likely to be
ringworm (tinea corporis) and can be treated with a topical
antifungal such as terbinafine. Identifying and treating the
source (cows, dogs, cats, etc) is helpful to prevent reinfection and also to prevent infection of other family members.
Tinea corporis
However, ringworm is not always ring-shaped and not all
annular rashes are due to ringworm. Further confusion can
arise if the patient has self-treated a rash with a myriad of
creams from pharmacists and well-meaning friends and
family. These treatments can alter the classical appearance
of the rash, particularly if the patient is applying a potent
topical steroid. Potent topical steroids dampen down the
inflammatory response to the fungus but usually promote its
spread, resulting in a more widespread, diffuse, non-specific
rash that cannot easily be identified as fungal in origin (tinea
incognito). This can often look like a patch of eczema or psoriasis, prompting the GP to use even more potent steroids.
Any attempts at stopping the steroid will usually result in a
rebound exacerbation of the rash (see Table 2).
If there is any suspicion that the rash is due to a fungal
infection, take skin scrapings for fungal stain and culture.
It can take two to four weeks to get the result back. Not
only will the culture confirm that you are dealing with a
fungal infection but it will also give you clues as to the
likely source of the infection (from animals, humans, the
soil, etc) and the most appropriate treatment. While waiting
for the results, treat on a best guess basis. It is reassuring
to know you have sent skin scrapings particularly if you are
tempted to try topical steroids while awaiting results.
The choice of treatment for a fungal skin infection is
dependent on the probable organism (dermatophyte or
yeast infection) and the extent and severity of the infection.
For localised dermatophyte infections, a topical allylamine
antifungal such as terfenadine, for one to two weeks, is
usually sufficient. For more extensive, severe infections you
may have to add in a longer course of oral terfenadine.
Some rashes can be due to a yeast (candida) infection
rather than a dermatophyte. Terfenadine has little or no
anti yeast activity, whereas imidazole antifungal such as,
ketoconazole or itraconazol have strong anti yeast activities.
Other imidazole antifungal such as micanozole or clotrimazole have both antifungal and anti-yeast activity and also
a weak antibacterial effect. These can be a good choice if
you are unsure if the infection is fungal, yeast, bacterial or
a mixed infection such as athlete’s foot or a groin infection.
Tinea pedis
Tinea pedis nearly always starts as an itchy rash between
toes, with scaly, white, macerated skin, most commonly
between the fourth and fifth toes. One foot is usually worse
than the other. Tinea pedis sometimes causes an allergic
(‘id’) reaction that causes pompholyx (blistering eczema) on
the soles of the feet and on the hands (see Picture 1). This
is more common in young women. If you see a person with
pompholyx on the hands, always look at their feet, as you
may find tinea pedis, which may be the cause.
Treating tinea pedis with an antifungal and the pompholyx with a potent topical steroid usually clears the rash.
It is important to advise patients with tinea pedis to wear
open sandals in summer and leather soled shoes in winter.
They should also be cautioned not to walk around barefoot, particularly in pools and changing rooms. As footwear
can harbour yeast or fungi, it is important to treat all shoes
with an antifungal powder, daily for one week. Tinea pedis
may also cause small cracks in the skin, allowing bacteria
to penetrate, resulting in cellulitis on the foot or leg. It is
important to treat the cellulitis with an antibiotic and also
the tinea pedis with an antifungal to prevent relapse.
46 FORUM November 2013
Tinea manuum
Tinea manuum usually causes a dry, slightly scaly rash
on the skin creases of the palm of the hand. It is usually
unilateral and can be associated with athlete’s foot (‘two
feet, one hand syndrome’). Skin scrapings from the scaly
palm creases usually clinch the diagnosis.
Tinea cruris
Tinea cruris causes an itchy, red, scaly rash in the groin
creases. It can be difficult to differentiate from intertrigo,
eczema, seborrhoeic dermatitis or psoriasis of the groin. Skin
scrapings can help to identify if a fungal infection is present.
Topical imidazole antifungals are usually better than terfenadine as they have anti yeast and antibacterial effects as well
as antifungal effects. Sometimes combining an imidazole
antifungal with 1% hydrocortisone can help to dampen the
inflammatory aspects of the infection, while the antifungal
is beginning to have an effect. Underlying causes should be
identified and managed to prevent relapse (diabetes, obesity,
poor hygiene, antiperspirants, soaps, bubble baths, etc).
Tinea capitis
Tinea capitis is more common in children under the age
of 12. It is usually caused by infections from cats, dogs or
cattle. It causes round patches of hair loss, but unlike alopecia areata, it also causes skin inflammation with redness
and scaliness of the skin in the bald area. Skin scrapings or
plucking hair from the affected areas may grow the fungus.
Treatment is with oral terfenadine for four to six weeks.
Griseofulvin is not as effective and is not easily available.
Occasionally, tinea capitis can cause a severe allergic reaction, resulting in a boggy, pussy, oozing mass on the scalp
with regional lymphadenopathy (a kerion). Treatment may
require a combination of oral antifungals, oral antibiotics
and oral steroids. If not treated early, a kerion may cause
permanent scarring and a bald patch. Tinea capitis is more
common in patients of African origin and tinea violaceum is
the most common organism isolated in this group .
Tinea barbae
Tinea barbae is most commonly found in the beard area
in farmers and causes an inflammatory, pustular, crusty,
unilateral rash that responds to three to four weeks of topical or oral terfenadine.
Tinea unguium
Tinea unguium can often be confused with other conditions that cause nail dystrophy, such as psoriasis, paronychia
or onychogryphosis (see picture 2). Fungal toenail infections
are usually harmless and asymptomatic. The only indication
for treatment is cosmetic. If the patient insists on treatment,
nail clippings should be taken as proximally as possible to
the infected nail to include some subungal debris for fungal
stain and culture. I usually withhold treatment until the
results are back, as the type of organism involved will dictate
the appropriate treatment. Mild, superficial fungal nail infections may respond to topical treatment such as amorolfine
nail lacquer, twice-weekly for three to six months.
Infection can be due to a dermatophyte (eg. trichophyton
rubrum or tinea interdigitale), yeast (candida) or moulds.
If a dermatophyte infection is isolated (eg. tinea rubrum),
I usually treat it with oral terfenadine for three to four
months. Yeast infections respond better to oral itraconazole. Routine blood should be checked before starting oral
therapy and repeated one month into a three or four month
Forum
Dermatology
Table 1: Common fungal and yeast skin infections
• Tinea
• Tinea
• Tinea
• Tinea
• Tinea
• Tinea
• Tinea
•T
inea
• Tinea
pedis (athlete’s foot)
corporis (ringworm on the body)
cruris (jock itch)
manuum (hand infection)
unguium (onychomycosis, fungal nail infection)
capitis (scalp ringworm)
barbae (beard ringworm)
incognito (when masked with a potent topical steroids)
versicolor (pityriasis versicolor)
Table 2: Clues to a fungal/yeast origin of a rash
• Asymmetrical rash
• A unilateral rash
• Annular rashes
• Slightly raised scaly borders
• Ill-defined borders
• Satellite lesions
• Animal contacts
• Patients of African origin
•U
nresponsive or worsening with potent topical steroids
•R
ebound of the rash when potent topical steroids are stopped
course of treatment to ensure no adverse reactions. Success
rates range from 40-80% with oral therapy.
Laser and IPL (intense pulsed light) treatment have been
shown recently to have a good antifungal or an anti-yeast
effect by heating the subungual skin and killing the organism. I usually treat all the infected nails with IPL for 60
seconds at an energy level that causes some discomfort
under the nail. We repeat this treatment once a week, for
three to four weeks. Success rate is similar to that of oral
antifungal therapies without the inherent risks of drug side
effects. It can take six to 12 months after completing oral
or laser treatment before the nail grows out clear and it
is important to explain this to the patient at the outset.
Relapse rates are quite high over the next five to 10 years.
Tinea (pityriasis) versicolor
Tinea (pityriasis) versicolor causes a low grade, faint,
slightly itchy, slightly scaly, blotchy rash, mainly on the
trunk in adults. The colour of the rash can vary from brown to
white (versicolor) according to the season and the area of the
skin involved. Skin scrapings should identify the offending
commencial yeast (malassezia) but are rarely necessary as
the diagnosis is usually obvious on clinical grounds. Treatment is with a topical anti-yeast agent, such as ketaconazole.
Ketaconazole shampoo can be used as a lotion and 5-10ml
can be applied from the neck down to the thighs and to the
wrists for 15 minutes daily for seven days. The patient needs
to be warned that the scale and itch will go immediately after
treatment, but the pigment changes can take six to 12 weeks
to fade. Relapses are quite common and some patients have
to treat themselves every spring. Malassezia yeast can also
cause a truncal folliculitis (pityrosporum folliculitis), which
may require systemic anti yeast treatment, such as ketoconazole or itraconazole.
David Buckley is in practice in Co Kerry
References available on request
FORUM November 2013 47