The most common medical
helminthes, which are of dermatological interests, associated with skin
Americans, Ancylostoma duodenale, Strongyloidesa and larva migrans.
Tissue round worms :
Filariasis , Loasis and Dracunculosis .
Taenia solium and
and cutaneous Schistosomiasis.
DUE TO NEMATODES
|(Thread worm, pinworm,
Pinworms are the
commonest of the human helminthes affecting mainly children.
Fig. 153. Ova of entrobius vermicularis
Infestation is due to
ingestion of food or drinks contaminated with the eggs of the parasite or
via infested fingers. The eggs mature in the rectum where after two weeks
the eggs hatch and the female migrates out of the anus especially at night
to lay more and more eggs .
During its migration, it
causes intense itching, where by scratching the eggs may be carried under
the nails or on the finger to cause a common way for re-infection.
Ingestion of the nematode
eggs, most commonly carried by finger nails contaminated during scratching
the anal area.
Infested dust, in which
eggs may survive for up to 13 days.
Skin excoriation and
Nocturnal pruritus: anal
, vaginal and perineal itching at night which may be severe causing sleep
disturbances and irritability.
secondarily infection and nocturia due to severe itching vulvar irritation
and mucoid discharge.
salpingitis are rare complications .
Other symptoms are
irritability , insomnia and enuresis .
Peri-anal itching and the
detection of worms in the stool are diagnostic.
Scotch tape is fixed on
the peri-anal area better in the morning then removed and mounted on a
glass slide and examined by the low power microscope may show the ova of
General hygiene - the
children should be instructed to wash their hands thoroughly after using
the toilet and before eating.
Keeping the nails shortly
General hygiene for the
bed linen, toilets and houses to eradicate the ova. Changing the underwear
and bed linens. Boiling of suspected clothes and linens at least during
The bedroom vacuum is
cleaned especially if the floor is covered with carpets.
citrate (Antepar) is the drug of
choice. This is given in single daily dose of 65 mg./kg. body weight or
one large single dose (not exceeding 2500 mg.), taken one hour before
breakfast mixed with Senna for eight consecutive days is very effective .
The drug is safe but should not be given in renal impairment or
uncontrolled cases of epilepsy.
100 mg/kg and (Pyrantel pamoate)
10 mg/kg are also effective.
is an effective drug given in a
single dose of 100 mg . In case of re-infection treatment is repeated
after two weeks giving 100 mg. Mebendazole twice daily for three
consecutive days .
pamoate (Povan-Park-Davis ) is
given in a single dose of 5mg./kg.of body weight. This can be repeated
after one week . It should be noted that the stools during using the
medication becomes bright red.
(Mintezol Merck - Sharp & Dohme): The dose is 25mg.//kg. body weight
given in two equal doses in one day and can be repeated after one week .
Antihistamine syrup may
be needed to relieve severe distressing itching. Topical steroid cream can
be used if itching is severe and persistent .
Dracunculosis is a
chronic infestation due to the nematode, Dracunculus medinensis.
Dracunculus medinensis, Guinea worm or Medina worm is a thread worm where
the female may reach a length of more than one meter. The disease occurs
in India, West Africa in East and Central Africa , Saudi Arabia, Yemen,
Iran, Pakistan and the West Pacific. Infestation occurs by drinking water
contaminated with a small crustacea belonging to the genus Cyclops (water
fleas ) .
The adult female worm
matures over a period of one year in man and discharges larvae through an
ulcerated skin lesion. Thousands of these larvae are produced,
particularly when the ulcerated area becomes on contact with water; these
survive for 3-4 days and can develop further in water fleas (Cyclops) .
Infestation of man
follows drinking water usually from wells, containing infested Cyclops
species, the larvae are released and penetrate the intestine. Further
maturation occurs in the retroperitoneal space or other sites where mating
occurs after about 3 months and the males subsequently die.
The females grow and
migrate downwards, usually to the lower limbs. The female penetrates the
skin of the leg and can then discharge larvae after exposure to water.
When the leg is immersed
in water a milky fluid loaded with the larvae is ejected, where after
complete ejection of the larvae the worm dies. The Cyclopes ingest the
ejected larvae where larvae complete their life cycle there.
are usually mild and begin when the larvae begin to migrate to the skin.
The general manifestations are mild fever, headache, malaise and
Skin lesions are in the
form of papule at the site of the worm under the skin, which becomes a
vesicle and a large bulla, which ulcerates, where the head of the worm may
be seen in the ulcer as a tortuous thread like .
Fig.154b. Dranculosis : multiple papules,vesicles and
Generalized urticaria and
mild itching are common. All the general manifestations may subside after
ulceration of the skin and the worm begins to extrude their larvae.
infection of the ulcer may cause more destruction to the tissues.
Supplying fresh water,
cleaning, and disinfecting wells from Cyclopes.
Fig. 154. Medena Worm lesion
Boiling water in endemic
areas may kill Cyclopes .
The treatment of choice
is injection of Phenothiazine in olive oil emulsion usually kills the worm
Much care should be
considered in order not to pull it too hard which may cause unwanted
separation of the worm leaving a retained part in the subcutaneous tissue
preparations such as Metronidazole given daily for about one week, which
can kill the worm, which then extracted gently through the skin .
Traditional method of
The natives in the
endemic areas has their own traditional way to get red of the worm:
As soon as a part of the
worm becomes apparent through the skin surface, the infested leg is
immersed into water for some time .
The worm extends more of
its body in the presence of water .
The patient has an experience to pull
gently the extruded part and rewinds it on a stick. He repeats this
procedure daily cautiously and with great care and patience till complete
extraction of the worm .
Schistosomiasis is a
serious systemic disease, which is caused by different species:
or blood flukes: Rashes may occur
during the invasive stage of the disease after penetration of the skin or
the mucous membranes by cercaria. The skin is being penetrated by
cercaria, and later there may be skin involvement at or near mucocutaneous
surfaces and less commonly at more distant sites on the trunk, following
dissemination of ova.
second group of non-human Schistosomes
cause cutaneous symptoms only. "Swimmers itch" or cercarial
dermatitis is an example of this type.
manifestations of Cutaneous Bilharziasis
Schistosome dermatitis is
due to invasion of the cercaria in to the skin during swimming or wadding
Itching and transient
erythema after the bather leaves water which decreases after few hours to
recur again .
Fig. 155. Biharzial granuloma
Erythematous macules and
papules appear on areas immersed in water. The condition may last for few
days where spontaneous recovery is usually the rule.
Mild cases need no
topical steroid may be required to relive itching.
Rubbing and drying the
skin by a towel may relieve the itching .
reactions: in the early weeks of the disease
Urticaria lesions usually
develop after penetration of the skin by cercaria. Urticaria may be severe
and called sometimes urticarial fever.
granuloma and fistulous tracts.
This may begin with mild
symptoms such as itching and erythematous macular or papular eruption due
to penetration of the cercaria to the skin from contaminated water
sources. The symptoms usually disappear after a short time. Few years
later the manifestations are more severe due to involvement of the
internal organs and the skin .
Late skin manifestations
are in the form of urticaria, ulceration of the skin and bilharzial
granuloma mainly on the external genitalia, which is cauliflower like
vegetation. A hard nodular or plaque type of bilharzial granuloma may
appear also on the trunk that becomes darkly pigmented and scaly.
Ectopic sites of egg
deposition probably arise through migration of adult worm via the
paravertebral venous plexus.
Skin involvement may
occur either as a result of the initial penetration of the skin by
water-borne free living cercaria or in the later stages of infestation
following ectopic localization of worms or ova.
In ectopic cutaneous
Schistosomiasis the ova may become deposited in the skin as well as in
other ectopic sites such as conjunctiva, trunk, lungs and central nervous
The periumbilical area is
a common site but other areas may be involved. In some cases, the lesions
have a segmental or zosteriform distribution.
features of Ectopic Bilharziasis
The primary lesion is a
flesh-colored, ovoid , firm papule reaching a size of 2-3 mm. These
papules form slightly raised plaques with irregular contours and
The skin over old nodules
may become deeply pigmented, scaly, and may later ulcerates. Hypopigmented
patch may develop after healing.
B. General manifestations of bilharziasis
Fever, purpura, malaise,
arthralgia, abdominal cramps, and diarrhea .
The symptoms resolve in
about 4-6 weeks.
Systemic manifestations of bilharziasis
Intestinal involvement .
Urinary tract involvement
Kidney and bladder
infection, which may lead to carcinoma of the bladder. Heart, central
nervous system and retina may be infested with the protozoa.
Prevent contact of human
excreta from coming in contact with water. Eradication of snails.
Tarter emetic or
Stibophen , Triostan and Astiban all are different medications used for
treatment of bilharziasis .
Niridazole ( Ambilhar) is
also very effective drug .
Amoebiasis is a very
common disease caused by Entemeba histolytica. The disease is endemic in
all warm and temperate parts of the world with low standard of living and
low sanitary conditions .
The prognosis is serious
in neglected case particularly in infants.
dysentery - this is due to
invasion of the trophozoites to the mucosa of the large intestine .
lesions - these are blood born
due to escape of amoebae from the bowel to blood stream causing metastatic
abscesses particularly in the liver.
Most of the lesions begin
as deep abscesses, which rupture and form ulcerations with distinct raised
, cord-like and thickened edges , surrounded by an erythematous halo . The
base of the ulcer is covered with necrotic tissue and hemopurulent pus in
which amoebae are present.
develops when invasive amoebae escape from the bowel to skin mainly on the
trunk, abdomen, external genitalia and buttocks.
Cutaneous Amoebiasis can
spread very rapidly and may terminate fatally, so early diagnosis and
treatment is important.
A solitary lesion may be
mistaken for an epithelioma, tuberculosis and verrucosa cutis.
Mucous membranes may be
involved when amoebae are implanted in the mucosa, most commonly that of
the vagina, cervix uteri or glans penis and rarely in the mouth.
Fresh smears :
Examination of fresh
material from the cutaneous lesion regularly discloses amoebae. Material
should be taken from the edge of the ulcer avoiding necrotic tissue, and
examined at once under the microscope. The demonstration of motile
trophozoites containing red blood cells is diagnostic.
Are helpful for rapid
screening especially in school children.
examinations should be performed.
recommended adult dose is 800 mg orally three times daily for 10 days.
This may be combined with Diloxanide furoate 500 mg three times daily or
followed by oral Diiodohydroxyquin, 650 mg three times daily for 21 days,
to eliminate intestinal cysts.
Local cleaning of
cutaneous ulcers with antiseptic solutions may be necessary.
Hepatic abscess needs to
be drained, this is most safely done by needle aspiration.
Effective treatment is
usually followed by complete healing of the skin lesion without any need
for plastic surgery.
Trichomonas vaginalis is
a disease of adults but due to direct or indirect infection of young ages
, it is included briefly in this chapter .
Trichomonas vaginalis is
found worldwide affecting all races, but more common in Negroes.Although
infection is commonest in the second and third decades, young age even
babies may be infected .
Many adults are
asymptomatic carriers - particularly males. It can be isolated from up to
15% of men with non-specific urethritis.
Discharge in males is
Direct infection during
sexual intercourse .
babies and young children may be infected from infected parents .
The condition is
frequently associated with gonorrhea .
transmission has been reported.
Fig. 156. Trichomonas vaginalis organism
The organism invades the
vagina and urethra in women, causing vaginitis and vulvitis with a
characteristic pale yellow frothy discharge. Trichomoniasis
characteristically causes a copious discharge with vaginal soreness or
irritation and urinary frequency.
The odor of the discharge
is often unpleasant although this feature is not specific. In many cases
bubbles can be seen in the discharge . The vaginal mucosal and cervical
surfaces are infested and sometimes covered with punctate hemorrhages.
Vulva soreness and
pruritus with inflammation of the surrounding skin are common, whereas
infection of Skenes or Bartholin's glands with abscess formation rarely
In males the condition
occurs with non-specific urethritis in up to 5% of cases, and balanitis
may also occur.The organism may be harbored in the prostate without
Standard treatment for
adults is with Metronidazole 400 mg twice daily for 5 days.
Single dose treatments
(four tablets, 500 mg.) can be given as a single dose is also effective.
Simple douching may relieve vaginal
symptoms (20-ml vinegar to one liter of warm water).
Creeping eruption is a
skin eruption, caused mainly by the larvae of hookworm Ancylostoma
Brazilians and to a lesser extent by other larvae as that of Ancylostoma
Cranium, horse bottle fly or larvae of strongyloides that penetrate the
skin during walking barefooted especially in children. The commonest sites
involved are feet, buttocks, genitalia and hands.
The condition is common
in all warm climates.
Adult hookworms live in
the intestines of dogs and cats and the ovae are deposited in the animals
conditions of humidity , warm and in sandy , shady areas, hatching of the
ova into infective larva which can penetrate human skin.
Infections are acquired
by children in sandpits, plumbers under houses, farm-workers under
outbuildings, hunters in hides, gardeners from the soil and sea bathers
from the sandy shore above the ebb and flow of the tides.
Mild itching at the site
of penetration of the larva into the skin. Later itching becomes more
severe with excoriation and secondary infection to the sites.
Tortuous thin, red lines
are formed along the way where larvae migrate into the skin. This line is
interrupted by small papules where the larvae hide in.
These larvae may be
removed from the skin during severe itching and may be detected under the
Some cases of creeping
eruption may show patchy infiltrate of the lungs with Eosinophils
Antihistamines orally and mild topical steroid to combat severe itching .
Antibiotics in cases
complicated by secondary bacterial infection .
Freezing of the larvae by
ethyl chloride spray is an old and effective.
(Mintezole-Merk Sharp & Dohme) :
Dose 25mg. twice daily
for two successive days .
The treatment of choice
is the topical application of 10% Thiabendazole.
Either the commercially
available oral preparation may be used directly, or two 0.5 g tablets of
Thiabendazole are triturated in 10g petrolatum, and applied twice daily,
where 95% of the tracks clear within a week. Oral Thiabendazole is less
effective and more toxic.
Albendazole 400 mg daily
by mouth for 3 days is safe and often effective.
"dew itch" is an eruption mainly on the soles, interdigital
spaces and ankles due to skin penetration by larvae of the hookworms
Ancylostoma duodenal, Necator Americans, and the roundworm Strongyloides
The disease is prevalent
in tropical and subtropical areas.
symptoms: are more severe in
children such as anemia debility ,lack of concentration , circulatory ,
nervous and digestive disturbances.
manifestations : appear 2-3
months before the systemic involvement by the hookworm .
lesion: Erythematous macules and
papules appear at the site of penetration of the larvae into the skin.
Later vesicles, pustules and ulceration are formed .
The ulcer is indolent,
irregular with rounded slightly elevated edges covered with necrotic
purulent exudate.Severe itching and urticarial lesions may occur during
the course of the disease where later the skin becomes pale or earth
Detection of the ova of the hookworm in the feces.
Necator Americans. Children dose is - 0.06 cc per pound of weight while
adult dose is 5 cc given with skimmed milk. Fats and oils should be
avoided . No need for purgation.
is also effective .
It should be noted that
if ascaris coexist with ancylostoma , ascaris should be treated first with
Alcopar before using Tetrachloroetheylene.
The adult worms live in
the jejunum with the head firmly attached to the mucosa and cause
bleeding. Bleeding leads to anemia, hypoproteinemia, digestive
disturbances and retarded development. Thousands of eggs are passed in the
feces, which can resist dryness.
conditions of warmth and humidity, eggs are hatched into motile
rhabditiform larvae. After 5 days and further they molt into infective
filariform larvae. They migrate upwards through soil and grass, and after
a period of contact with human skin, the larvae penetrate the skin.
Walking barefoot is the
commonest method of infection. Favorable places for transmission include
soil around houses such as plantations, cultivated fields, and mines.
After penetrating the
skin, larvae migrate within a day or two via the blood stream to the
lungs, pass up the bronchial tree where they are swallowed and pass down
to the esophagus, reaching the duodenum and jejunum. These mature in 4-6
In passing through the
lungs they cause acute alveolitis or pneumonitis.
can be reached by:
seen radiologically (characterized Leoffler‘s syndrome).
be confirmed by detection of the characteristic eggs in the feces.
Ground itch is treated
symptomatically, with an antipruritic cream such as crotamiton and 1%
Pulmonary symptoms, if
severe, respond to corticosteroids.
respond to a three day course of Albendazole or Mebendazole
Oral iron is given for
iron deficiency anemia .
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