Genital Infestations Flashcards

1
Q

What is phthirus pubis

A

Pubic lice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is phthiriasis diagnosed?

A

Pubic lice - Can be seen by the naked eye
Nits (eggs) - seen with naked eye - adhere to hairs
Examination under light microscopy can confirm morphology if necessary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Treatment of phthiriasis

A

Malathion lotion or permethrin cream.
All body hair should be treated.
All bedding should be washed at high temperatures.
Sexual partners need treatment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Transmission of phthirus

A

public lice transmitted by close body contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

incubation period for phthirus (lice)

A

incubation period usually 5 days to several weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Symptoms / signs of phthirus (lice)

A

itching
can be asymptomatic
visible lice or nits (eggs)
Blue macules (maculae caeruleae) may be visible at feeding sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What areas can be affected by phthirus (lice)

A

Adult lice infest coarse hairs of the pubic area, body hair and, rarely, eyebrows and eyelashes
Eggs (nits) are laid which adhere to the hairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Management of phthirus pubis (lice)

A

Lotions more effective than shampoos
apply to all body hair including beard + moustache
A second application after 3-7 days

  • Malathion 0.5%. Apply to dry hair- wash out 2 - 12hrs
  • Permethrin 1% cream - Apply to damp hair- wash out 10min
  • Phenothrin 0.2% - apply to dry hair - wash out 2hr
  • Carbaryl 0.5 and 1% - Apply to dry hair - wash out 12 hr

avoid close body contact until they + partner(s) completed treatment + follow-up
full STI screen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Treatment of pubic lice infestation of eyelashes

A

permethrin 1% lotion - keep eyes closed - 10 minute application
OR
inert ophthalmic ointment with white / yellow paraffin base applied to the eyelashes BD for 8-10 days - works by suffocating lice - avoids risk of eye irritation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

treatment of phthirus pubis (lice) in pregnancy or breastfeeding

A

Permethrin is safe

Permethrin 1% cream - Apply to damp hair- wash out 10min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Advice for sexual partners of patients with phthirus pubis (lice)

A

Examine and treat current sexual partners should be examined and treated
Contact tracing - partners in last 3 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

follow up for patients treated for phthirus pubis (lice)

A

Review at 1 week - re-examine for absence of lice
Treatment failure should be given an alternative
Dead nits may remain adherent to hairs - does not imply treatment failure - nits can be removed with a nit comb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is scabies

A

Sarcoptes scabiei var hominis

human itch mite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Lifecycle of scabies mite

A
lifecycle of sarcoptes = 4-6 weeks
Mites burrow into skin + lay eggs
eggs hatch 
~10% grow into adults in 10 - 15 days
female lays ~25 eggs and dies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Transmission of scabies

A

close skin contact
frequently sexually acquired
mites can live off a host for 24-36 hours
Fomite transmission is uncommon but can occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is format transmission more common in crusted scabies

A

greater number of mites present

and mites can survive longer - up to 7 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Symptoms of classical scabies infection

A

intense generalised itching
worse at night
due to delayed type-IV hypersensitivity reaction to mites, and mite faeces + eggs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How long after primary infestation do symptoms of scabies occur

A

Symptoms begin 3-6 weeks after primary infestation
earlier ( 1-3 days) in a re- infested person
Scabies is infectious before the rash develops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

signs of scabies infestation

A
most common = erythematous papules
excoriation 
characteristic distribution 
pathognomonic lesion= burrow -linear intra-epidermal tunnel = short wavy greyish/ white threadlike elevations of 2-10mm length
Nodular lesions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Anatomical sites commonly affected by scabies

A

interdigital webspaces / sides of fingers / under finger nails
flexor aspects of wrists / extensor aspects of elbows
anterior + posterior axillary folds
around nipples / penis + scrotum / umbilicus
upper medial thighs / buttocks / sides + back of feet

Spares face + scalp

21
Q

what is Norwegian scabies

A

Crusted scabies / Scabies crustosa / Norwegian scabies) occur in immunocompromised states

22
Q

When does crusted scabies occur

A

occur in immunocompromised states

e.g. in AIDS, leprosy, lymphoma, systemic or potent topical steroids, organ transplant recipients, elderly

23
Q

what proportion of patents with crusted scabies have no identifiable risk factor (e.g. no immunocompromised)

A

40%

suggests possible genetic susceptibility

24
Q

Symptoms / signs of crusted scabies

A
Erythematous 
scaly 
crusted lesions 
can be malodorous 
associated with fissuring 
can affect any part of the body including the face and scalp 
itching may be mild or absent
25
If a healthy patient contracts scabies from a patient with crusted scabies what type of scabies will they develop?
classical scabies | unless also immunocompromised / genetically susceptible to crusted scabies
26
complications of crusted scabies
Sepsis - as fissures associated with crusted scabies provide an entry point for bacteria
27
Can humans contract animal scabies?
``` Humans can rarely contract scabies from pet dogs (canine scabies = Sarcoptes scabiei var canis) or cats (feline scabies = Notoedres cati.) ``` incubation period is shorter lesion distribution confined to sites of contact with the animal burrows not seen self-limiting as mites do not reproduce in humans hosts treatment of animal only
28
what is Scabies Incognito
``` altered clinical presentation following use of topical steroids widespread atypical papular lesions may mimic generalized eczema Symptoms are masked but patient remains infectious ```
29
Diagnosis of scabies
clinical history and distribution / appearance of skin lesions. +/- Microscopic identification of mites / eggs / faecal pellets (scybala) from scrapings +/- burrow ink test +/- dermoscopy
30
Preparation of a skin scraping for microscopy in suspected scabies
``` Scraping of the skin burrows with a scalpel blade Place specimen on a glass slide Add 10% potassium hydroxide ( dissolves excess keratin) OR ``` Apply a drop of mineral oil to the lesion Scrape away the entire lesion with the scalpel blade transfer to slide
31
What is the burrow ink test for suspected scabies
Apply black / blue ink to suspected papule remove surface ink with alcohol wipe t positive test = characteristic dark zigzagged line running away from the lesion = ink tracking down mite burrow
32
Differential diagnosis for scabies
``` Impetigo folliculitis papular urticaria atopic dermatitis contact dermatitis dermatitis herpetiformis psoriasis seborrhoeic dermatitis pytiriasis rosea secondary syphilis lymphoma ```
33
Complications of scabies
Secondary bacterial infection - staph aureus / group A β-haemolytic strep / peptostreptococci resulting in impetigo / folliculitis / furunculosis / ecthyma / abscess Secondary eczematisation due to constant scratching / irritant effects of medication glomerulonephritis leucocytoclastic vasculitis
34
what is furunculosis
a deep infection of the hair follicle leading to abscess formation with accumulation of pus and necrotic tissue = furuncle (i.e. boil)
35
treatment options for scabies
- permethrin 5% cream - malathion aqueous 0.5% liquid - benzyl benzoate 25% emulsion (not recommended) - oral ivermectin (less effective than permethrin) [topical ivermectin not available in UK]
36
why is benzyl benzoate 25% emulsion not recommended as treatment for scabies
not as effective as Permethrin or Malathion | may cause skin irritation
37
General advice for patients with scabies
Hot wash (60°C) - bedding / clothing / towels used during the previous four days before or by dry-cleaning or by sealing in a plastic bag for at least 72 hours
38
Recommended regimen for Permethrin 5% cream to treat scabies
Permethrin 5% cream - apply to whole body from the chin + ears downwards - pay special attention to areas between the fingers / toes / under nails - apply treatment to cool dry skin - allow lotion / cream to dry before dressing in clean clothing - Wash off cream after 8 - 12 hr - reapply 1 week later. - if hands are washed with soap within 8 hours then reapply cream
39
Which groups of patients with scabies should be advised to apply permethrin cream to the whole body including face + scalp
people who are immunosuppressed the very young the elderly people
40
Recommended regimen for Malathion 0.5% aqueous lotion to treat scabies
Malathion 0.5% aqueous lotion - apply to whole body from the chin + ears downwards - pay special attention to areas between the fingers / toes / under nails - apply treatment to cool dry skin - allow lotion / cream to dry before dressing in clean clothing - Wash off cream after 24 hr - reapply 1 week later. - if hands are washed with soap within 24 hours then reapply
41
Alternative regimen for scabies treatment | i.e not Malathion or Permethrin
Ivermectin - oral - dose 200 mcg/kg 2 weeks apart - available on a named patient basis. - used in the treatment of crusted scabies that does not respond to topical treatment alone - adverse events associated with ivermectin = rash / vomiting / abdominal pain
42
Treatment of crusted scabies
Combination treatment topical permethrin cream OD for 7 days then 2x weekly until cure + oral ivermectin (200 mcg/kg) on days 1,2,8,9 and 15 should be isolated + barrier nursing Treat all household members
43
Management of post scabetic itch
crotamiton 10% cream (2-3 times a day) Or - if the scabies mites have definitely been eradicated - use topical hydrocortisone 1% Night time sedative antihistamine may help emollients for dry skin/eczema
44
What is post scabetic itch
Itching may continue up to 2 weeks after successful scabies treatment Treatment failure suspected if new burrows appear or if itching persists >2-4 weeks
45
Treatment of scabies in pregnancy and breastfeeding
Permethrin 5% cream. Alternatively use Malathion 0.5% aqueous liquid remove the liquid or cream from the nipples before breastfeeding and reapply afterwards Avoid oral antihistamines during pregnancy
46
Treatment of sexual partners of patients with scabies
Examine and treat - Current sexual partners - household members - others with close personal contact Contact tracing = 1 month
47
Follow-up for scabies
not generally required Return if pruritus persists >2 weeks Return if new burrows appear
48
for scabies which treatments has there been documented resistance to?
documented resistance for both permethrin and ivermectin