Parasitic Infestations Of The Skin PDF

Parasitic Infestations Of The Skin Dr.Sarah Raed Assistant Lecturer of Dermatology, Duhok College of Medicine Infestation of mites of sarcoptessa.cl  Seven years itch disease Scabies ‫ﺟرب‬ ‫ﮔورﯾﺑون‬ Sca...

Parasitic Infestations Of The Skin Dr.Sarah Raed Assistant Lecturer of Dermatology, Duhok College of Medicine Infestation of mites of sarcoptessa.cl  Seven years itch disease Scabies ‫ﺟرب‬ ‫ﮔورﯾﺑون‬ Scabies is an infectious parasitic infestation of the skin caused by the highly host-specific mite called (Sarcoptes scabiei var. homini), which Causes a diffuse, pruritic eruption.  Life Cycle Of The Mite The life cycle of mites is completed entirely on human skin. proteolytic enzymey The female mite, by a combination of chewing and body o motions, is able to excavate a sloping burrow in the stratum corneum hayeggs A few hours after burrow digging, the fertilized female begins egg laying at a rate of 2-4 ova per day. ess day The eggs & mite fecal pellets (Scybala) are deposited behind the advancing female in the burrow. Scybala are dark, oval masses may act as an irritant and may be responsible for some of the itching. say  Eggs hatch in 10 to 12 days and larvae leave the burrow to mature on the skin surface. d After the larvae molt, they become nymphs which can only o survive 2 to 5 days off host. MMI The male mite lives on the surface of the skin and enters burrows to procreate no Copulation occurs in the burrows. The male dies immediately after copulation within the burrow, whereas the female dies after laying the eggs. n58  Epidemiology ❑ Scabies is a worldwide issue that affects all ages, races, and all socioeconomic levels ❑The incidence of scabies is increased in overcrowded societies (poverty and poor hygiene), Mentally-defective institutions, Prisons, Wars conditions. ❑ Transmission of Scabies: direct prolonged Usually through non-casual skin to skin contact such as prolonged hand-holding or sharing of a bed. Sexual transmission is common, especially among young adults. less commonly through indirect spread by use of contaminated towels, bed linen and clothing (the mites survive for 2-3 days at room conditions).  4–6 weeks after first infestation there may be no itching, but thereafter it dominates the picture, often being particularly bad at night. In contrast, in second attack, itching Clinical Features: starts within day or two, because these victims already have immunity to produce the itchy allergic reactions. In first-time infestations, the incubation period before symptoms g develop can range from 2–6 weeks before the host’s immune system becomes sensitized to the mite or its products, resulting in pruritus and cutaneous lesions. In contrast, a subsequent infestation often becomes symptomatic o within 24–48 hours. Asymptomatic scabies-infested individuals are not uncommon, and they can be considered “carriers” o Nocturnal pruritus is highly characteristic feature of scabies. The Primary Lesions: (Burrows and Vesicles) 0 Burrows are pathognomonic lesions of scabies. They are short (5-15 mm), grayish or skin-colored, slightly elevated, linear, curved or S-shaped lesions. Burrows are few to many in number. However, Scratching destroys burrows; therefore they don’t appear in some patients. I 12 of Burrows may be found on the scalp, face, palms and soles babies and elderly, whereas these sites are usually spared in adults Only in infancy scabies affect the face  a Vesicles are seen mainly in finger webs and sides of fingers are isolated , pinpoint and filled with serous rather than purulent fluid. Vesicles or pustules may be found on the palms & soles in infants. The Secondary Rash (Excoriated Papules) ❖Widespread pruritic, small, discrete red papules. ❖Usually have generalized distribution. e NFY.IQ ❖May represent a Hypersensitivity reaction to the mite or its products. ❖Rarely contain mites. Tito Indurated, crusted nodules can be seen in infants and young children on intertriginous areas as well as on the trunk Predilection sites Finger webs & Sides of the fingers Sides of hands & feet Wrists flexors Antecubital fossae Axillae Areolae of breasts ( ) Periumbilical region Lower abdomen Genitals ( : Penis and scrotum) Buttocks  Crusted scabies (formerly called Norwegian scabies) is found in individuals with compromised immune systems, such as the elderly, people infected with HIV and solid organ transplant recipients.00 echinus It can also occur in those with decreased sensory functions and/or ability to scratch (e.g. patients with leprosy or paraplegia). hyperkeratotic plaques develop diffusely on the palmar and plantar regions. Although, patients with crusted type have a large number of mites they have a little or no itching and they are highly contagious.  The most dramatic part of the eruption is usually on the trunk, Do not search for the mite or movement of mite here bcs they are too small to see. Look instead for burrows where female mites lay their eggs Scabies. Several thread-like burrows are present in the web spaces of the fingers and on the knuckles, a common location for these lesions in scabies.  0 Penile involvement with erythematous papules and nodules is characteristic of scabies in males  o Erythematous papules, linear burrows, areas of crusting and acral vesiculopustules in two infants with scabies Nodular scabies in an infant  iii Crusted scabies: in which a patient with impaired sensory function had an asymptomatic hyperkeratotic hand “rash”  Diagnosis The epidemiologic history (e.g. pruritus in household members or other close personal contacts), the distribution and types of lesions, and nocturnal itching form the basis of the clinical 8 diagnosis. Confirmation of the dx can be achieved by light microscopic exam. of mineral oil preparations of skin scrapings (from infested areas) for adult mites, eggs or fecal pellets. A scalpel or curette may be used to obtain the skin sample. Microscopic examination of transparent adhesive tape following its application to infested areas of skin represents another diagnostic technique. Dermoscopy can prove useful for direct visualization of mites & eggs Differential Diagnosis ✓Atopic, allergic contact, and nummular dermatitis ✓Dermatitis herptiformis Herpitform ✓Arthropod bites Insect ✓Psychogenic pruritus  Management Recommendations: ✓Close contacts of a patient who itch, must be treated. ✓All sexual contacts and all family members of the patient should be treated whether they itch or not. ✓Clothing and bed linens should be laundered or left without use for few days. ✓Systemic antihistamines may help to reduce itching especially at night. ✓Systemic antibiotics are given if there is secondary bacterial infection.  Anti Scabicides are the mainstay of treatment. They should be thoroughly applied to all areas below the neck with a special care s pervillain must be paid to burrow-bearing areas. Antiscabitic agents 1. Permethrin 5% cream ✓First choice for treatment of scabies in children and adults. ✓The safest & most effective medication for scabies. ✓Safe in pregnant (category B) and lactating women and babies > 2 months. ✓Applied once for 8-10 hours and then washed off. One application is effective but a second treatment one week after the 1st application is now standard practice. 2. Sulfur 5-10% precipitated sulfur in petrolatum is safe and very effective treatment. It is safe in babies, pregnant and lactating women. 0 It should be applied nightly for 3 nights and washed off 24 hours after last application. Sulfur is messy and has bad odour, however its main side-effect is skin irritation. Sulfur-induced dermatitis occurs specially with higher concentrations, repeated or prolonged applications. 3. Benzyl benzoate lotion (25%) Applied in a way similar to sulfur. Skin irritation is the main side effect. 4. Crotamiton (10%) [Eurax® cream] Weak scabicidal agent (cures only 50-60% of patients) but has the advantage of being antipruritic. It should be applied twice daily on 5 successive nights. 5. Ivermectin Safe and effective in treatment of scabies. verified Given at a dose of 200 μg/ kg and may be repeated 2 or 3 times at intervals separated by 1 or 2 weeks. 200m41 Indications: it is better option than topical therapy in: ✓Cases refractory to topical treatment. 213h ✓Epidemic or endemic scabies in institutions. ✓Superinfected scabies ✓Crusted scabies  Pediculosis ‫ره ﺷك و ﺳﭘﻰ‬ Pediculosis is a parasitic infestation caused by a mite (lice) called Pediculus. There are two genera of lice causing three clinical types of pediculosis: Pediculus humanus var capitis (Scalp louse) of Pediculus humanus var corporis (Body louse) Pediculus pubis (Phthirus pubis) (Pubic louse) The life span of the adult louse is about one month. Lice suck blood. Their eggs attached to hair or clothing, known as nits. main feature of all lice infestations is severe itching, followed by scratching and secondary infection.  Pediculosis Capitis This worldwide infestation is caused by bloodsucking, wingless, E six-legged insects that live only on the hairs of the scalp, most commonly occurs in children between the ages of 3-12 years. O diagnostic Presence of eggs (nits) firmly attached to scalp hairs is most common sign of infestation. hits Spread by close physical contact and sharing of hats, combs, brushes, and pillows. to Lice can be dislodged by air movement, blow-dryers, combs, and towels, and passively transferred to fabric, facilitating new infestations Pediculus humanus capitis rang A nit is cemented to a hair shaft  Itching and excoriation Clinical Features Secondary bacterial infection which might cause LAP Papule in back of neck Mass Itching of variable degree is the main symptom in P. capitis. Excoriations may accompany severe itching. Many patients may present with secondary bacterial infection. So any child presents with impetigo of the scalp especially of the occipital region, should be checked for P. capitis. Some patients may present with lymphadenopathy (cervical or sub-occipital) due to secondary bacterial infection. Some females esp. those with long hair may present with excoriated red papules at the back of the neck due to skin irritation by mites or nits that come in contact with the neck. Hair may become matted in a purulent mass ass. with a bad odor in heavy scalp infestation. Differential Diagnosis of Head Lice: T Psoriasis , Seborrheic dermatitis (dandruff) Piedra( fungal infection) Delusions of parasitosis encircling the hair 27 Pediculosis capitis Treatment Apply one of the following Pediculocides: Pyrithrin Shampoo Permethrin Rinse [1%] Lotions are more effective than shampoos Malathion Lotion [0.5%] Lindane Shampoo or Cream [1%] Applied any of these agents to the scalp and left for 10 minutes for shampoos or 8-12 hours for lotions or creams and then washed off. Another application should be repeated after 7 days to kill any skipped hatched ova. All family or school contacts should be checked and treated if infested. Give systemic antibiotics if there is secondary bacterial infection or lymphadenopathy. Pediculosis Corporis (BODY LICE) Body infestation with P. humanus var corporis which is the largest of three lice infesting human. Occurs mainly in dirty people (e.g. beggars). and waists is the main complaint. 0 Severe itching mainly on the trunk and specially in the axillae tuna axial unit Pruritus is usually associated with linear excoriations, crusts of dried blood or serum & hyperpigmentation. Transmission occurs via infested clothes or bed sheets. Diagnosis may be confirmed by finding the lice or their nits in the inner seams of clothes. Treatment of P. Corporis Discarding (if possible) or laundering & dry cleaning of the clothes is necessary to kill the lice and nits. Topical insecticide regimens similar to those used for scabies can eradicate concurrent scabies or crab lice infestations as well as kill any body lice adherent to hairs. 5% permethrin cream rinse or 1% lindane lotion Antihistamines to reduce itching. Systemic antibiotics for 2ndary bacterial infections.  Pediculosis Pubis (CRAB LICE) Best to call “crab lice” (rather than “pubic lice”) as infestations may involve other hair-bearing sites such as mustache, beard, axillae, eyelashes, eyebrows Transmission Sexual contact occurs mainly in young adults (STD), however non-sexual transmission through skin to skin contact or sharing clothing or bedding may occur. Presentation Itching & excoriation. It may be complicated by secondary bacterial infection + lymphadenopathy (usually inguinal). Mites are few in number and may migrate from the pubic area to other hairy areas such as abdomen, chest, axillae and eyelashes.  Mites are seen as 1-2 mm brownish-gray specks in hairy areas. Nits are attached to the hairs as tiny and shiny whitish-gray specks few to many in number. Black dots may be found on the inner aspect of the underwear of some patients (blood sucked by lice and passed in their feces). Eyelashes may be infested especially in children. It may be misdiagnosed as seborrheic blephiritis (erythema, scaling and nits). Treatment Shaving is not curative as the louse will seek another hairy area of the body to reside. Topical therapy options similar to pediculosis capitis, but oral Ivermectin is the preferred tx. O Antihistamines (reduce itching). Systemic antibiotics (Secondary bacterial infection). Treat any infested sexual partner or other contacts. Eyelashes infestation is treated by applying a thick coat of Vaseline twice daily for 8 days followed by mechanical removal of any remaining nits.  Crab lice Both adult crab lice and nits are evident on pubic hairs Crab lice nits and feces on the eyelashes.