skin ectoparasites


Gale mite human

introducedon :

It is a cosmopolitan ectoparasitic disease, highly contagious, due to skin colonization by a mite Sarcoptes scabiei, variety man

Épidémiologie :

  • Affection common worldwide, affects all individuals regardless of gender or ethnicity
  • Transmission :

Contact human direct : skin against skin, usually within a couple (Sexually Transmitted Infection) or family

indirect : rarely, by contact with the laundry or especially bedding

  • parasitology : mandatory human parasite, lifetime 1 at 2 month, the female lays 3 at 5 eggs per day in the groove of the surface layer of the epidermis. Each egg will hatch, giving a larva and nymph and an adult 20 days. The Sarcopt adult does not survive more 1 at 2 days outside its host

CLinique :

  • Form typical :

Incubation : 3 weeks for initial infestation, 1-3 days if re-infestation

Sign subjective : pruritus +++ : diffuse, sparing the face and back, at night upsurge, often marital or family

lesions objectives :

Non-specific : Frequently, due to scratching

Topography : evocative, interdigital spaces, volar wrist, elbows, umbilicus, buttocks, inner thighs, external genitalia in men, nipple and areola in women

specific : rarer, to search systematically

furrows scabious : path of the female mite in the stratum corneum, winding lesions a few millimeters long, visible especially between fingers and on the front of the wrists,  can be detected by staining at anchor, each furrow contains eggs laid and, at one end, is a discrete elevation corresponding to the position of the female mite

vesicles  beaded :  small translucent elevations,  based on an erythematous base, sit especially in the interdigital spaces

Nodules  scabious :  papulo-nodules,  purplish red,  prurigineux,  sometimes excoriated, especially sitting on the axillary regions and human genitals

  • shapes clinics :

Gale of infant : in addition to the already mentioned signs, include vesicular-pustules

palmar and plantar (+++), scabious nodules peri-axillary, possible breach of the face

Gale profuse : characterized in profuse and widespread rash (including the back). It is the result of late diagnosis, sometimes an immune deficiency

Gale hyperkératosique (said Norwegian) : highly contagious

pruritus : often discreet or absent

Terrain : immunocompromised or elderly community

Clinique : achieving whole body, including the face, scalp and nails, with hyperkeratotic areas

Gale of the « people own » : misleading (pauci-car lésionnelle, very discreet specific signs), Diagnosis is based on history (pruritus and family background characteristics) and research specific lesions

shapes complicated :

Surinfection : impetiginisation lesions

eczematisation : secondary to mange or its treatment

Nodules post-scabieux : papulo- nodular lesions ubiquitous, CASTROTHEODORICIENS, red or coppery, can persist for several weeks after successful treatment. They are immuno-allergic

ISevolution :

  • Without treatment : it persists indefinitely and complicated
  • Under treatment : pruritus disappears, most of the time, in a few days, sometimes, it lasts longer (2 at 4 weeks). Beyond this time limit, one speaks of a post-scabious pruritus which can be linked to a reinfestation or persistence of the disease

Diagnostic positive :

The diagnosis is, first of all, clinical and is based on :

  • anamnesis (Night to strengthening family pruritus) and eruption cutaneous from topography evocative
  • Exam parasitological : must scratch a groove with a lancet, collect material from this groove by taking. The light microscopy can see the eggs or the adult female mite

Diagnostic differential :

body lice, Gale d'animal origin (giving humans pruritus with excoriated lesions, but no furrows), Other causes of pruritus

Traitement :

  • Goals : patient treatment, bedding and entourage
  • treatments local :

Benzoate from benzyl (Ascabiol®) : lotion 10%

Mode job : after a warm bath, on wet skin and respecting the face and mucous membranes, on applique : J1 -> 2 Applications in the evening 10 min intervals, J2, J3, J4 -> reapply without washing, J5 -> take a bath. In infants, a single brushing diluted ½, kept 12-24,  wrap hands to avoid accidental ingestion

Effects secondary :

Local : irritation, baking, contact dermatitis

generals : neurological toxicity if swallowed or cutaneous passage

organochlorine (Lindane : Scabécid®) : lotion 1%

Mode job : a single application to dry skin, apply the product and then rinse (after 12h in adults, after 6 hours in children). To renew 1 week after if failed

Effects secondary :

Local : irritation and contact dermatitis

generals : neurological toxicity (+++), kidney, haematological and hepatic

Cons-indications : child under 2 years, pregnant woman (increased risk of cutaneous passage)

Crotamiton (Eurax®) : cream 10%

Indications : symptomatic treatment of pruritus and scabious nodules

Mode d’application : 2 at 3 times a day

Other : Pyrethrine (Spregal®), Benzochloryl (DDT®), Vaseline sulfur (2-10%, especially for scabies in infants)

  • Treatment through way General : ivermectin (Mectizan®) : tablets 3 and 6 mg

Mode job : by reason of 200 mcg / kg fasted for 2h, is 1 tablet 3 mg/15 kg, a second dose 15 day intervals may be necessary

Indication : crusted scabies, scabies patients infected with HIV

Cons-indications : pregnancy, child under 15 kg 2 years

  • Measures General : disinfection of laundry and bedding 3 days preceding the treatment and during treatment (washed and ironed with a hot iron), those that can not be washed are put aside for 3 days or powder by Aphteria® for 48 hours in a large bag, Concomitant treatment of subjects even touch without clinical signs

Pédiculoses :

  • The pediculosis are ubiquitous diseases related infestation cosmopolitan bloodsucking insects : lice
  • Three species of lice can infect humans :

Pediculus humanus variety capitis : who lives in the scalp

Pediculus humanus variety body : lives in clothing and feeds on the body

Phtirius pubis (or inguinal) : who lives on the pubis

  • parasitology : lice are insects of 1-3 mm, visible to the naked eye, the female lays an average 10 lenses (eggs) a day that hatch in 8 days to give nymphs become adults 10 days. The female lives 1 at 3 months but can survive outside its host (few hours to P. capitis and up 3 weeks to P. body)

Pediculosis of the head :

  • It is due to the infestation of the scalp by the head louse (Pediculus humanus variety capitis)
  • Epidemiology : the most common pediculosis, preferentially affects school-age children (4-11 years), especially direct human transmission (contact) rarely indirect (through clothing or a hairbrush)
  • Manifestations clinics :

pruritus : Scalp (50% cases), especially in the temporal regions, occipital and post-auricular, may extend to the neck and upper back

lesions scratching : scalp and neck

➢ ± crusted lesions superinfected (impetiginisation), cervical lymphadenopathy or even a eczematisation (impetigo any neck or scalp must seek pediculosis)

  • Diagnostic from certainty : based on the finding live lice and the presence of nits (retro-auricular regions +++)

Pediculosis corporeal :

  • It is due to the infestation of the body by the body louse (Pediculus humanus variety body)
  • Epidemiology : much rarer than the pediculosis scalp, predominantly affects subjects in a state of insecurity, Direct human transmission (promiscuity night shelters) or indirect (clothing)
  • parasitology : lice circulates on the body time to feed, he then hides in clothes and lays eggs
  • Manifestations clinics :

pruritus : intense and widespread (related to sensitization to the saliva of the louse)

lesions from scraping : scattered on the trunk and the root member, can be hemorrhagic or superinfected, sometimes urticarial lesions or mélanodermiques

  • Diagnostic from certainty : the discovery of lice and nits on clothing or on the body when undressing

pediculosis pubis (phtiriase) :

  • This is due to a ectoparasitosis Phtirius inguinal, lice or pubic louse
  • Epidemiology : rare,  especially direct transmission through sexual contact (IS).  Indirect contamination, theoretically, possible by the towels or bedding
  • parasitology : unlike the head louse and the body louse who are highly mobile, adult lives attached to pubic hair and adjacent hairs (inguinal glutes, thighs, abs, chest) and sometimes axillary hair, the beard, eyelashes and eyebrows
  • Manifestations clinics : pruritus (pubic, sometimes armpit, beards, eyebrows ...), damage or local infection scraping ...
  • Diagnostic from certainty : discovery of lice and nits clinging to the emergence of hair

Treatment of pediculosis :

➢ The treatments are neurotoxic insecticides for lice ; whatever their class, they must have a pediculicide activity and lenticide

➢ The shampoos and powders are less effective than solutions, lotions or creams. The use of spray is against-indicated if the child or the parent user has asthma because of the risk of bronchospasm

  • Classes pharmacological :

Organophosphorés (Malathion :  Prioderm®) :  is the leader,  Lotion 0.5% for local application, avoided before 6 month, pediculicide and lenticide, an application, line by line, from 10-20 ml to the scalp and non-wet hair, then followed, 12h after a non-treatment shampoo, by rinsing with water and vinegar and careful combing

Pyréthrines : the application period varies by age and specialty used (a few minutes to hours), pediculicide and lenticide, they exist in many forms : lotion, solution, shampooing, crème. Example : item antipoux® shampooing (0.4%) and lotion (0.3%)

Lotion : applied to the base of the hair so as to moisten the entire scalp and hair, leave in contact 10 minutes then rinse

Shampooing : to put 8-20 ml on the scalp prewetted, good lather, leave in contact 5-10 minutes then rinse. 224 hours after application e

organochlorine  (Lindane : Scabecid®,  Aphteria®) : pediculicide but weakly lenticide, should be avoided (potential neurotoxicity). Aphteria® : left overnight, reapply the next day and 8 days

  • Indications :

Pediculosis of please haired :

Measures  individual :  first-line :  lotions containing Malathion (Prioderm®), for people living in the same household, only infected individuals are treated

Other measures : should be treated clothing and bedding in case of massive infestation : machine wash at 50 ° C of sheets, pillows, lint and bonnets. Combs and brushes are deceived in insecticide or isolated for 3 days

Pediculosis corporeal : decontamination of linen and bedding by Aphteria® powder is usually sufficient

Pediculosis pubis : pubic lice fall under the same treatment as pediculosis scalp, shaving the hair is sometimes necessary if nits are abundant, clothing and bedding are washed at 50 ° C, track other associated STI and treat partners