Arthropods and skin
Scabies Pdiculosis Cutneous leishmaniasisObjectives
Recognize risk factores for scabies and lice infestation Identify nits and burrows Discuss treatement of scabies and pediculosis Diagnose and treat cutaneosu lesihmaniasisArthropods and the skin Scabies Scabies is an intensely pruritic, highly contagious infestation of the skin by the arachnid mite Sarcoptes scabiei, variety hominis. the Greek words sarx (the flesh) and koptein (to smite or cut) and the Latin word scabere (to scratch). 0.2*0.1 mm for the male 0.4*0.3 mm for the female
SCABIES
Transmission of the mites from patients to another person needs long close contact, at least few minutes by Sharing bed , prisons .very close contact sexual contactLife cycle
Life Cycle adult fertilized Female (strtum corneum) burrow 3 mm/day Lay 3 eggs /day hatch after 3 days into larvae passes through 3 phases mature adult in 3 weeks the adult female repeat the cycleClinical manifestations
symptoms will not appear before 3 weeksif previously infested with scabies the patient will react after 2 daysNocturnal itching Primary lesionsBURROW. The linear, curved, or S-shaped burrows are approximately as wide as #2 suture material and are 2 to 15 mm long They are pink-white and slightly elevated. A vesicle or the mite, which may look like a black dot at one end of the burrow, often may be seen..Primary lesions
burrow location webbed spaces of the fingers, flexor surfaces of the wrists, elbows, axillae, belt line, feet, and scrotum in men and areolae in women. In infants, burrows are commonly located on the palms and soles.
VESICLES AND PAPULES. Vesicles are isolated, pinpoint, and filled with serous rather than purulent fluid Infants may have vesicles or pustules on the palms and soles
Secondary lesions
Pinpoint erosions are the most common secondary lesions. Pustules are a sign of secondary infection ( Figure 15-5 ). Scaling, erythema, and all stages of eczematous inflammation Nodules occur in covered areas such as the buttocks, groin, scrotum, penis, and axillae. The 2- to 10-mm indolent, red papules and nodules sometimes have slightly eroded surfaces, especially on the glans penisDiagnosis
History Clinical burrow genital lesion male InvestigationsA drop of mineral oil is placed on the lesion. Then, a sterile blade is used to gently scrape the burrow or papule. The lesion should be scraped 6-7 times, and bleeding should be avoided.
The skin scrapings are placed on a glass slide and examined under a light microscope at 40X magnification.
The burrow ink test can also be used to make the diagnosis of scabies. The tip of a fountain pen is rubbed along the site of a possible burrow. The ink penetrates the burrow, distinguishing it from the surrounding tissue. The excess ink is wiped off with an alcohol pad. This technique is particularly useful in children and individuals with very few burrows.
Use of topical tetracycline solution is an alternative to the burrow ink test. After application and removal of the excess tetracycline solution with alcohol, the burrow is examined under a Wood light. The remaining tetracycline fluoresces a greenish color. This method is preferred because tetracycline is a colorless solution and large areas of skin can be covered.
Treatment: General principles of treatment: These drugs should be applied to the whole body below the neck or even to the face and scalp in infants. Disinfection of beds & clothes for one week.Sun light exposure All contacts must be treated. Duration of treatment depends on the used agent.
Treatment The most important thing is to treat the patient and all the contact. In addition to oral antihistamin and topical steroid there are many antiscabetic remedies 1-sulphur 2.5% - 10% simple and effective and cheep but messy with offensive smell lifa and apply the sulfer fom neck to the toes daily for three successive days , 2-permethrin simple and single use applied as sulfer must be washed out after 12 hours 3-gamma benzene hexachloride (lindane)single application applied as sulfer washed out after 24 hrs . it is neurotoxic ,contraindicated in pregnancy . 4- benzyle benzoate very potent 24h, may cause scrotal irritation.
Oral ivermectin is very effective, but because of rare deaths in elderly patients, it is often reserved for refractory or extensive infections, such as crusted scabies. Scabetic nodule
in summery
Pediculosis It is an infestation of human with lice . A louse is a small wingless flattened insect, 6 legged, 3-4mm in length. Life cycle The mature adult female lays eggs on the surface of the skin Where the temp is optimum for eggs lays 8 eggs/ day hatches in 8 days into nymphs which require 8 days to become mature male and females The eggs also called nits produces cement material to attach firmly to the hair shaft with an angel of 45 degree.Transmission by Close contact Sharing clothes beds or combs The way children walk closely head to head for long time The adult louse survive for 1-3 weeks away from human.
Manifestations of head louse infestation include: scalp pruritus, impetigo. occipital lymphadenopathy Pruritus is the most common symptom of infestation. Children often have trouble sleeping Pruritus leads to excoriation, secondary bacterial infection, Examination of the scalp reveals excoriations, nits, and adult lice regional lymph node enlargement. The heaviest infestation typically is in the retroauricular scalp. commonly and.).
Nits and bites
Nits resemble scales Easly removed Clik sign Microscope Angle of attachemnetTreatment Permethrin shampo 5-10 mint comb Gamabenzene hexachloride Malathion Kerosin After 8 days repat
Pediculosis corporis: Body lice infest the seams of clothing and take blood meals at night. Nits are found in the seams, not on human hairs. the hemosiderin-stained purpuric spots where lice have fed, suggest the diagnosis of body louse infestation.
Clinical features Generalized ithing Pin point papule on trunk Scrach marks Treatment Clothing boiling Bedding disinfected with insecticides
Pediculosis pubis
Sexually transmitted disease Close contact Never affact scalp only eye lashes Clinical features Sever ithcing scrach marks secondary infctions /bleeding spots on the under wearPediculosis pubis
Treatment Shaving the area Gamabenzine hexachloride for 2 succesive days Sulpher for 3 days Repat after 8 dayscapitus corporis pubis
This disease caused by flagellated protozoa called leishmania with many subspecies. Classification: (1) Cutaneous Leishmaniasis: caused by L. tropica ,L. major ,L. ethiopica , L.mexicana, L. braziliensis (2)mucocutaneous Leishmaniasis:- caused by L.etheopica and L.braziliensis (3) Diffuse cutaneous Leishmaniasis: caused by L aethcopica and L.mexicana (4) Visceral Leishmaniasis:-caused L. donovani.LEISHMANIASIS
Cutaneous leishmaniasis
Causative agent Leish tropica dry type heales with minimal scaring Leish major wet ulcerative heals with ugly scar endemic Mode of transmission Female sand fly Definitive host human intermediate cat and dogs
Transmission by sand fly of genus phlebotomas (vector) the infective stage is flagellated form (promastigote) that enters the body by sandfly bite and taken inside body by macrophages and changed into the non-flagellated form (amastigote). Reservoir: - may be human but mostly domestic animals like cat, dogs
Incubation period Few days to few months Clinical features Solitory boil may be multiple ,persistant for more than 3w progress to nodule violatious may ulcerate or not
Diagnosis
is mainly clinical in our country and the golden role is:-any boil >l month duration is leishmaniasis until prove other wise Direct smear Culture in NNNmedia. Leishmanin skin test immunological tests Polymerase chain reactionSelf liminting 1y Affect exposed some time hidden Long lasting immunity Loss immunity 1-immune defficiency 2-new strain 3-long period
Treatment
Treatment goal period reduction and less scar Local Physical ; cryotherapy heating Chemical : intralesional pentostam , hyppertonic NaCL , zinc sulphate Systemic Multiple little child or important stie Na stibogluconate 10mg/kg/day for 10 days Zinc sulphate 100mg*2 orally for one month Rifadin, Metheprim, Metronidazole, Ketoconazole, itraconazoleQuestions
summeryScabies Pediculosis Cut leishmaniasis