CHAPTER 12

Lice are vector of certain diseases that may cause cutaneous and systemic diseases such as relapsing fever and typhus . Two species of lice can infest human body : Pediculosis humanus (head louse). This can infest the scalp and body causing pediculosis capitis and pediculosis corporis . Phthirus pubis: infests the pubic hair and the anogenital areas.

Fig. 133. Pediculosis capitis  (Nits along the hair shaft)

Pediculosis capitis is a common infestation of girls and boys with long hair. A school child is commonly infested due to direct contact with others in the classroom or in the playing ground. Infestation from personal fomites such as combs , hairbrushes and hair covers is common .

The commonest area infested is the occipital area and that which is near the ears. Lice are sometimes not easily found in the infested area but the nits are seen on the hair shaft .

1. Severe scalp itching .

2. Secondary bacterial infection causing folliculitis, impetigo and furunculosis.

The hair may be matted together with offensive smell due to the oozing and crusted bacterial lesion.

Cervical and occipital lymph nodes are enlarged .

3. Constitutional symptoms especially in infants and children are due to toxic bacterial absorption.

• Detection of the nits on the hair shaft or the parasitic lice .

• The disease should be suspected in any case of :

• Continuous scalp itching.

• Inflammatory scalp lesions .

 Enlargement of the occipital or posterior cervical lymph nodes especially in young girls.

1. Secondary bacterial infection is treated first.

2. Wet crusted lesions are treated by wet compresses such as Potassium permanganate 1:9000 twice daily followed by topical antibacterial preparation such as Muperacin (Bactropan Cream).

3. Oral antibiotics.

4. A antihistamines orally may be required to alleviate itching .

5. Gamma benzene hexa chloride ( Kwell lotion or shampoo ) is applied and rubbed to the scalp at night and shampooed next night .

   Another application may be required after two weeks .

This is an infestation of the body caused by body louse. The parasite is rarely detected on the skin . It is found clinging to the clothes where it pierces its probiscus into the skin and sucks blood .

Generalized itching, which may be severe. Excoriation of the skin with manifestations of secondary bacterial infections. Impetigo and furunculosis are common complications of pediculosis corporis .

The clinical picture may be diagnostic. Erythematous macular lesions where parallel excoriation and scratch marks appear on the shoulders . Hyper pigmentation of the affected areas may follow which is due to the effect of saliva of the lice, changing the bilirubin into beleverdin .

Pediculosis corporis is differentiated from scabies by the absence of burrows and the hands and feet are not involved.

Detection of the parasites or their eggs can be found on thorough search of the clothes .

Treatment of infested individuals by one per cent Melathione.

Crotamiton (Eurax ) cream or lotion.

Severe itching may need topical antipruritic preparation and oral antihistamines.

Pediculosis pubis is infestation of the pubic area. This is usually the only site infested and rarely other areas are involved as eyelashes, eyebrows, axilla and body hair.

Pubic louse is different from other types of lice by having greater width than length . They are small and sometimes not easily detected while their nits are glued to the hair shaft and the louse may be seen grasping the base of the hair shaft with their heads buried in the hair follicle.

Pediculosis pubis is rare in newborn and children. Infestation occurs from infested mother or father. Pediculosis pubis is sexually transmitted disease due to direct contact from infested individuals. Infestation from infested clothes, bed sheets, toilet seats and other infested garments may occur.

The pubic lice in children may infest and reside the eyelashes producing blepheritis and crusted lesions .

Lice may induce sever pruritus on biting while the skin manifestations may be inconspicuous apart from the scratch marks . A secondary bacterial infection is common complication as furuncles , pustular lesions and even abscesses .

One of the clinical and usually diagnostic features of pubic lice is the presence of pinpoint hemorrhagic minute spots on the underwear . Small-pigmented steel-gray spots resembling stain may be also found on chest , thighs ,upper arms and abdomen more prominent in light skinned individuals.

• Symptomatic: antihistamines to relieve severe itching and antibiotics for secondary bacterial infections.

• One percent D.D.T or Lindane spray for dusting the infested clothes.

• Shaving of the crural area may facilitate the creams or lotions to work in a better way .

• Crotamiton ( Eurax lotion and cream ) once daily for two weeks is effective medication .

• One percent Melathione and Gamma benzene is an alternative medications.

Bed bugs are distributed worldwide especially in crowded places , in camps and areas with lower hygienic conditions .

The parasite has a special smell where it attacks their victims at night to get its meal from human blood . The parasite punctures human skin by its probiscus where it injects a vasodilator and irritating substance into the human skin .

The reaction to the bite varies according to the site involved , type of patients and the age. The manifestations are more severe in infants and young children .

Mild reaction : may show minimal manifestations . One parasite may produce several bites mainly on the abdomen , buttocks and ankles . The reaction may be urticarial or purpuric associated with itching at the site of the bite .

Severe reaction: may be in the form of generalized urticarial lesions where the patient finds in the morning that his nightdress and bed linen stained with blood .

Improvement of the general hygiene especially in crowded places .

• Melathione 0.5 per cent, Pyrithium or Trichlorfon spray are used to dust small holes in the furniture, walls and floors where the parasites hide during the day.

• Methyl bromide fumigation for infested houses may be enough to eradicate the parasites .

• Fumigation by the use of sulfur is also effective .

• Mild topical steroid to relieve pruritus .

• Systemic antihistamines may be needed for severe cases especially for sensitive patients .

Several species of ticks attack human causing skin and systemic manifestations . Ticks are found on grass or bushes and attack also animals as dogs .

Ticks transmit Rocky Mountain fever , tick born encephalitis and Q-fever.

In children ticks may cause tick paralysis if the tick is attached to the skin and not removed immediately .

The female tick attaches itself to the skin and sucks blood from the superficial vessels by its probiscus till the body of the parasite becomes engorged with blood . This may take two weeks after that the tick leaves the skin and fall .

• Systemic manifestations :

1. Tick pyrexia - the manifestations begin by fever, chills, headache, abdominal pain and vomiting .

2. Tick paralysis - this occurs one week after the tick attaches itself to the neck and back of the head of the victim . This type of paralysis, which is of the flaccid type involves, the neck and limbs resembling infantile paralysis.

3. Other systemic manifestation are respiratory failure, dysarthria and dysphagia may be another manifestation of the disease .

• Skin manifestations :

  Macular erythematous lesions with arciform or circinate edges appear on the site of insect bite mainly on the trunk and extremities .

  Punctate hemorrhagic macules or nodules may appear at the site where the insects bite the skin .

  Erythema migrans - The lesion has a chronic course lasting for few months.

1. Eradication of ticks is a very important preventive measure.

   DDT - dusting crowded areas with DDT, in refugee or military camps and schools.

2. Removal of the clinching tick to the skin surface leads to dramatic relief of the tick paralysis.

   Removal of the tick from skin will cause relief of these symptoms within 24 hours.

   Removal of the tick should be complete. Every possible care should be considered in order not to leave their probiscus into the skin .

Hold the tick gently from the area near its mouth by a forceps, raise its body by a needle inserted between the tick and the skin, and try to gently remove it. The site of the bite must be immediately disinfected.

3. Diethyltolamide ( Deet ) is very a effective repellent .

4. Indalone and dimethyl phthalate are also effective in eradicating ticks.

Rickettsia diseases are systemic bacterial infections transmitted by blood sucking arthropods such as ticks and lice.

These diseases include :

Typhus, Rocky Mountain, spotted fever, Rickettsia Pox and Scrub typhus.

Epidemic typhus is caused by Rickettsia prowazeki, which is transmitted by lice, while rat flea transmits Murine typhus or endemic typhus.

1. Epidemic Typhus

   The organisms are present in the feces of the lice, which by scratching or minor trauma can penetrate the skin causing local and systemic manifestations.

a. Prodromal symptoms - appear after an incubation period of about one week . These manifestations include fever , chills ,aches and generalized pain.

b. Skin manifestations - pinkish macular eruption appears after five days on the trunk, which becomes later on hemorrhagic and gangrenous lesions affecting mainly the fingers, toes, nose and the ear lobes. The face palms and soles are usually spared .

There is conjunctival injection with photophobia.

3. General manifestations:

   Psychic disturbances such as delirium and hallucination is a characteristic of the disease .

   Myocardial damage leads to pulse irregularities and hypotension that may lead to coma .

   Leukopenia, anemia.

   The patient becomes week and debilitated .

Complement fixation test.

OX-19 test demonstrates the antibodies in infected persons .

2. Endemic Typhus

   Fleas transmit the disease . The clinical manifestations are the same as that of epidemic typhus, but milder without gangrenous lesions .

3. Tick Typhus (mediterranean fever )

   Tick typhus is caused by R. conori, which is transmitted by the dog tick. The disease is endemic in countries of the Mediterranean areas and in many parts of Africa and India. The disease affects mainly children .

Indurated papule at the site of the tick bite appears which later ulcerates. Characteristic black eschar appears at the site of the bite with the febrile exanthema. Macular or maculopapular eruption later appears on the trunk, palms and soles.

The course, manifestation and treatment of the disease is the same as that of epidemic typhus .

4. Spotted Fever (rocky mountain spotted fever)

   Rocky Mountain spotted fever is an endemic febrile disease caused by R. Rickettsia that is transmitted by ticks from various types of animals such as rabbits, rodents and ticks living in shrubs and grasses .

   Spotted fever is the most virulent type of the rickettsia infections. If the tick is infected, it remains so through out its life where the virulence of the organisms increases after the tick takes a blood meal .

The incubation period is about one week. The onset of the disease begins with a prodroma of high fever lasting for 2-3 weeks, chills, generalized pain and prostration .

Skin eruption appears on the first week, begins on the wrists , ankles and then becomes generalized with purpuric eruptions .

Systemic manifestation are due to involvement of other systems :

Neurological manifestation : meningeal irritation leads to convulsions and disorientation.

Flushing of the face and epistaxis is a common manifestation .

Gastrointestinal disturbances

1. General measures

           Protection from tick bites .

          Dusting places inhabited by the lice using the special repellents .

         Effective delousing is necessary to control spread of infection.

2. Specific treatment

   Active treatment by using broad-spectrum antibiotics is curative .

   Tetracyclines are the drugs of choice and treatment should be started as soon as the clinical diagnosis is made. The drug is given in full dose as a standard course.

   Doxycycline: epidemic typhus and scrub typhus respond to a single dose of 200 mg Doxacycline .

   Chloramphenicol is also effective and has been recommended for Rocky Mountain spotted fever in pregnant women and children under 8 years old.

   General supportive measures are necessary in severe cases.

    

This disease is due to tick bites .

Erythematous patch appears at the site of inoculation. The eruption appears within a week after the bite due to spirochete inoculation. The skin lesion is usually an erythematous ring, enlarging at a rate of several centimeters per week. The course of the skin lesion is chronic and may take few months or even a year.

In some cases the erythema is intense, in others it is rarely detectable. The erythematous lesions may be entirely flat or show elevation at the center, or the periphery or in both areas. Slight scaling is occasionally seen.

Older areas of residual erythema may become dusky blue. There may be a zone of clearing behind the advancing ring producing a target-like morphology.

Moderate burning or itching occurs in one third of cases.

Dissemination of the infection may occur within days or weeks of inoculation. Spirochetes have been detected in the affected organs.

Meningitis, cranial nerve palsies and peripheral radiculoneuritis.

Myocarditis, pericarditis, conduction defects and carditis may be seen in some cases .

Migratory joint pains, myositis, conjunctivitis .

Bartonellosis is an infectious disease transmitted by species of Phlebotomus and is caused by the small, rod-shaped organism Bartonella bacilliformis. The incubation period is from 2 to 6 weeks. Two forms of infection are recognized:

1. Oroya fever

2. Verruga peruana

These are known to represent two stages of infection. In the first stage (Oroya fever) there is high mortality and the second stage isVerruga peruana.

The onset is characterized by severe pernicious anemia, leukopenia and the appearance of immature leukocytes with a clinical picture of anemia and leukemia. The disease may be fatal. It has a sudden onset of pyrexia accompanied by a rapidly progressive hemolytic anemia, hepatosplenomegaly, generalized lymphadenopathy, septicaemia and salmonella infection may appear in the course of the disease.

Erythematous, cherry red, multiple hard, verrucous papules appear in crops and often become nodular or pedunculated mainly on the face, neck and limbs.

Some lesions become very large, others may be hemangiomatous or hemorrhagic petechiae or ecchymotic rash may develop. The mucous membranes may be involved .

Verruga peruana may develop without previous Oroya fever or may follow  after weeks or months l. Lesions may persist for months or years and lesions heal with fibrosis.

One characteristic of the disease is that the eruption may be present in different stages of evolution in the same patient. Lesions may persist for months or years.

The diagnosis can be reached by the following:

1. The clinical picture .
2. Anemia fever, asthma, joint pains adenopathy when appear in patient has visited the endemic area should give a suspicion .

3. Blood picture: anemia, leukemia and leucopenia

4. Blood film: detection of the spirochetes 

5. Blood culture on Noguchi leptospira medium is positive in both stages of the disease.

Verruga peruana must be distinguished from yaws, acquired hemangiomata and Kaposi‘s sarcoma (including AIDS).

Verruca peruana show lesions containing numerous small blood vessels with endothelial proliferation. There is a variable infiltrate of chronic inflammatory cells .

In Oroya fever the organism can be seen in blood films or isolated in blood cultures.

Avoiding infested areas .

Penicillin in small doses destroys the B. bacilliformis .

Chloramphenicol 2 g/day for a week is the treatment of choice because of the frequent coexisting salmonella infection with the disease.

1. Alexander JO‘D. Infestation with Anoplura - lice. In: Arthropods and Human Skin. Berlin: Springer-Verlag, 1984: 29-55.

2. Maunder JW. The appreciation of lice. Proc Roy Inst Great Britain 1983; 55:1-31.

3. Bowerman JC, Comez MP, Austin RD et al. Comparative study of permethrin 1% creme rinse and lindane shampoo for the treatment of head lice. Pediatr Infect Dis J 1987; 6: 252-5.

4. Di Napoli JB, Austin RD, Englender SJ et a1. Eradication of head lice with a single treatment. Am J Public Health 1988; 78: 978-80.

5. Cratz NG. Epidemiology of louse infestations. In: Orkin M, Maibach HI, eds.

6. Cutaneous infestations and insect Bites. New York: Marcel Dekker, 1985: 187-98.

7. Juranek DD, Jessup CA, Coll B. Pediculosis: the Philadelphia school problem.

8. Maunder JW. Pediculosis corporis; an updating of attitudes. Environ Health 1983; May: 130-2.

9. Burns DA. The treatment of Pthirgus pubis infestation of the eyelashes. Br J Dermatol 1987; 117: 741-3.

10. Kalter DC, Sperber J, Rosen T et al. Treatment of pediculosis pubis. Arch Dermatol 1987; 123: 13l5-19.

11. Rasmussen JE. Pediculosis and the pediatrician. Pediatr Dermatol 1984; 2: 74-9.

12. Dolan DL, Mckinsey JJ. Removing a tick. North Carolina Med J 1985; 46: 471.Dermatol 1981; 8: 157-9.

13. Heyl T. Tick bite alopecia. Clin Exp Dermatol 1982; 7: 537-42.

14. Jones BE. Human ‘seed tick‘ infestation. Arch Dermatol 1981; 117: 812-14.

15. Sherman WT. Polishing off ticks. New Engl J Med 1983; 309: 992.

16. Jones BE. Human ‘seed tick‘ infestation. Arch Dermatol 1981; 117: 812-14.

17. Sherman WT. Polishing off ticks. New Engl J Med 1983; 309: 992.

The human flea is worldwide , inhabiting cervices in floors , walls and furniture of houses, sand or earth, and occasionally deposits eggs on clothing.

Fleas can cause skin lesions such as macular, urticarial lesions with characteristically a small punctate hemorrhage at the sit of bite.

Fleas transmit many dangerous diseases such as Murine typhus, plaque, tularemia and others .

Papular urticaria is the most common skin manifestation of fleabites and varies according to site, and age of the patient, and whether the skin is sensitized or not by the fleabite.

Newborn infants are not sensitized to the fleabite so the reaction is usually severe at the beginning.

Young children are mainly affected by urticarial lesions on the exposed areas of the face and extremities. Papular, wheals and even bullous lesions appear in highly sensitized individuals .

Later on when sensitization occurs after the first attack the reaction is minimal and may pass without notice as in adults who are usually exposed to repeated fleabites .

Mild topical steroid ointment .

Oral anti histamine.

Eradication of the fleas from clothes and domestic animals as cats and dogs by spraying by five percent DDT.

The impregnated female sand flea (Tunga penetrans) is the burrowing flea into the skin, where most of her body is buried into the skin , while her posterior part is apparent out. The female flea sucks blood and becomes huge in size.

Hard itchy nodule appears at the site where the female buries itself into the skin of soles, feet, ankles and interdigital areas. This may lead to pustular lesion that may suppurate leading to an ulcer. The female flea may be seen as a dark plug representing the posterior part of the female flea . More than one pustule may be seen due to impregnation of the skin with more than female flea. These lesions may coalesce together forming a boggy nodulo-pustular lesion.

If the burrowing flea persists for a long time and not removed from the skin, this may lead to deep and extensive ulcer, gangrene, lymphangitis, septicemia and rarely this may be fatal.

Preventive measures :

Avoid walking barefooted. Use the appropriate shoes .

Good hygiene of the feet .

Infested areas are treated by D.D.T or Lindane or by fire to the site where the female flea has burrowed the skin .

Gauze soaked with chloroform or ether applied to the area may be enough to kill the flea .

The pustule is opened and the flea is removed.

Oral and topical antibiotic is needed to treat the pustules or the ulcers .

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2. Chua EC, Goh KJ. A flea-borne outbreak of dermatitis. Ann Acad Med Singapore1987; 16: 648-50.

3. Hunter KW, Campbell AR, Sayles PC. Human infestation by cat fleas; Ctenocephalides (Siphonaptera: Pulicidae), from suburban Raccoons. J Med Entomol 1979; 16 (6): 547.

4. Medleau L, Miller WH. Flea infestation and its control. Int J Dermatol 1983; 22: 378 9.

5. Basler EA, Stephens JH, Tschen JA. Tunga penetrans. Cutis 1988; 42: 47-8.

6. Alexander JO‘D. Tungiasis. In: Arthropods and Human Skin. Berlin:                  Springer-Verlag, 1984: 171-6.

7. Basler EA, Stephens JH, Tschen JA. Tunga penetrans. Cutis 1988; 42: 47-Sanusi ID, Brown EB, Shepard TC et al. Tungiasis: report of one case and review of the 14 reported cases in the United States. J Am Acad Dermatol 1989; 20: 941-4.

Bed bugs suck blood from their victims at night and hide during the day in clothes, furnitures or on the floor. Bed bugs are available in crowded places such as refugee camps, military camps and prisons. Bed bugs can cause skin manifestations on biting the skin and are considered as vectors for systemic diseases such as Trypanosomiasis .

Pruritic, burning wheal with a central hemorrhagic punctum at the site of the bite. Itching is not severe to wake the individual from his sleep and this why that the bug takes its time easily to bite several areas.

In children the reaction is more severe so that vesicular or bullous reactions occur at the top of the wheal. The wheal does not last long, it may disappear after a few hours although sensitization to bug saliva may occur resulting in sensitization and eczematization.

The most common sites involved are the neck, back, buttock, ankles and wrists. Secondary bacterial infection is due to severe scratching and excoriation of the skin.

Kissing bugs of the genus Triatoma transmit Trypanosomiasis and cause skin manifestations characterized by painful, pruritic papules, bullae and nodules .

Eradication of bugs by spraying 5-10 % DDT to the places inhabited by bugs .

Symptomatic treatment for itching and secondary bacterial infection .

1. British Museum (Natural History) economic series no. 5. The Bed Bug. London: Trustees of the British Museum (Natural History), 1973.

2. Jupp PG, Lyons SF. Experimental assessment of bedbugs (Clectularius and Cimex hemipterus) and mosquitoes (Aedes aegypti formosus) as vectors of human immunodeficiency virus. AIDS 1987; 1 (3): 171-4.

Beatles may cause skin irritation due to the Cantharidin present in their knee joints, genitalia and prothorax . The beetles excrete this material only when disturbed as by crushing or even slightest pressure when they are moving on the skin .

Mild tingling and stinging sensation at the site where the Cantharidin secreted from the beetles becomes in contact with the skin. Later on a bulla may develop after a few hours. More than one blister may occur, usually in one line and appear may be seen next morning where the beetles usually wonders at night . The parts involved are usually the exposed areas of the bodies as the extremities .

Rarely accidental introduction of the eggs or larvae in traumatized skin, nasal, or ocular cause cantheriasis with severe local manifestation as myiasis caused by the fly larvae .