Skin Infections and Infestation Flashcards Preview

10. Year 2: Dermatology > Skin Infections and Infestation > Flashcards

Flashcards in Skin Infections and Infestation Deck (108)
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1
Q

What are some examples of skin infections?

A
  • Impetigo
  • Folliculotis
  • Cellulitis
  • Erysipela
  • Syphilis
  • Leprosy (Hansen’s disease)
  • Rickettsial disease (spotted fever and scrub typhus)
2
Q

What is leprosy also known as?

A

Hansen’s disease

3
Q

What is impetigo?

A

Common and highly contagious skin infection that mainly affects infants and children. Impetigo usually appears as red sores on the face, especially around a child’s nose and mouth, and on hands and feet. The sores burst and develop honey-colored crusts.

4
Q

What is the most common bacterial infection in children?

A

Impetigo

5
Q

What are some predisposising factors to impetigo?

A
  • Warm temperature
  • High humidity
  • Poor hygiene
  • Skin trauma
6
Q

What bacteria usually causes impetigo?

A

Caused by staph aureus, to a lesser degree strep pyogenes

7
Q

What is the treatment for impetigo?

A
  • Local wound care
  • Topical antibiotics
8
Q

What is folliculitis?

A

Infection of hte hair colliculi

9
Q

What bacteria most commonly cuses folliculitis?

A

Staph aureus

10
Q

What are some predisposing factors to folliculitis?

A
  • Occlusion
  • Maceration and hyperhydration
  • Shaving or waving
  • Topical corticosteroids
  • Diabetes
11
Q

Where on the body does folliculitis normally occur?

A

Normally occurs on face, chest, back, axillae or buttocks

12
Q

What investigation is useful with folliculitis?

A

Bacterial culture cna help identify causative orgnanisms

13
Q

What is the treatment of folliculitis?

A
  • Antibacterial washes
  • Antibacterial ointments
14
Q

What is erysipelas?

A

Infection of dermis with lymphatic involvement, most commonly caused by group A streptococci

15
Q

What bacteria most commonly causes erysipelas?

A

Group A streptococci

16
Q

Who usually suffers from erysipelas?

A

Disease of the very young, elderly, the dehilitated and those with lymphedema or chronic cutaneous ulcers

17
Q

What is the clinical presentation of erysipelas?

A

Erythema with well defined margins

Affected skin fells hot, tense and indurated

Affects face and lower extremities

18
Q

What is required to diagnose erysipelas?

A
  • Clinical
  • Lab may show an elevated leukocyte count with a left shift
19
Q

What is the treatment of erysipelas?

A
  • 10-14 day course of penicillin
20
Q

What is cellulitis?

A

Infection of the deep dermis and subcutaneous tissue

21
Q

What is cellulitis most commonly caused by?

A

Strep pyogenes and staph aureus

22
Q

What are risk factors for cellulitis?

A
  • Lymphedema
  • Alcoholism
  • Diabetes
  • IV drug buse
  • Peripheral vascular disease
23
Q

What is the clinical presentation of cellulitis?

A
  • Affected areas show
    • Rubor (erythema)
    • Calor (warmth)
    • Dolor (pain)
    • Tremor (swelling)
  • Lesion has ill-defined non-palpable borders
24
Q

Describe the lesion due to cellulitis?

A

Ill-defined and non-palpabe borders

25
Q

What is required to diagnose cellulitis?

A
  • Clinical
  • Leukocyte count is usually normal and blood cultures are negative in most cases
26
Q

What is the treatment of cellulitis?

A

Antibiotics

27
Q

What is syphilis?

A

Complex sexually transmitted infection (STI) caused by bacteria Treponema Pallidum

28
Q

What is syphilis caused by?

A

Treponema pallidum

29
Q

What is the clinical presentation of syphilis?

A

Episodes of active disease followed by latent periods

Widespread rash and flu like symptoms develop next (secondary syphilis)

If left untreated tertiary syphilis may develop years layer and cause a variety of problems:

  • Affecting brain, eyes, heart and bones
30
Q

What can happen if syphilis is left untreated?

A

If left untreated tertiary syphilis may develop years layer and cause a variety of problems:

  • Affecting brain, eyes, heart and bones
31
Q

What investigations are done for syphilis?

A
  • Serological tests turn positive about 5 to 6 weeks after acquiring infection
  • Non-specific non-treponemal tests (VDRL)
  • Specific anti-treponemal antibody tests (TTPA)
32
Q

What does VDRL stand for?

A

Non-specific non-treponemal tests

33
Q

What does TTPA stand for?

A

Specific anti-treponemal antibody tests

34
Q

What is the treatment of syphilis?

A
  • Penicillin by injection depending on stage of disease
35
Q

What are the different kinds of syphilis?

A

Primary syphilis

Secondary syphilis

Tertiary syphilis

36
Q

What is the clinical presentation of primary syphilis?

A

Initially syphilis appears as painless sore (ulcer) where infection entered:

  • Usually around genitals, anus or mouth
  • Sore is known as a chancre
  • Single small firm red painless papule quickly ulcerates
37
Q

When does primary syphilis advance to secondary?

A

3 weeks to 3 months after 1st stage, widespread rash occurs:

  • May be subtle or appear as rough, red or reddish brown papules or patches
  • Occurs typically on trunk and often affects palms and soles
  • Does not itch
38
Q

What is the clinical presentation of secondary syphilis?

A
  • May be subtle or appear as rough, red or reddish brown papules or patches
  • Occurs typically on trunk and often affects palms and soles
  • Does not itch
39
Q

In what phase of syphilis is the patient infectious and can transmit to their partner?

A

Tertiary syphilis

40
Q

What is the clinical presentation of tertiary syphilis?

A

Normally no signs on clinical examination:

  • Solitary granulomatous lesions (gummas) may be found on skin, in mouth and throat or occur in bones
  • Brain, spinal cord, heart, liver, eyes may also be affected
41
Q

What are some examples of viral skin infections?

A
  • Herpes simplex
  • Chicken pox
  • Shingles
  • Viral warts
  • Molluscum contagiosum
42
Q

What does HVS stand for?

A

Herpes simplex virus

43
Q

What are the different kinds of HSV?

A

HVS 1

HVS 2

44
Q

What is herpes?

A

Orobalial and genital infection

45
Q

What is the clinical presentation of HSV1?

A
  • Presents usually between 20-40 years old
  • Often asymptomatic in children <10 years
    *
46
Q

What is HSV2?

A
47
Q

What is the clinical presentation of HSV2?

A

Sore areas with erythematous base, with vesicles followed by pustules and ulcerations

48
Q

What is the treatment of herpes?

A

Antiviral therapy depends on type (topical or systemic)

49
Q

What is the aetiology of chickenpox and herpes zoster (shingles)?

A

VZV

50
Q

What is the medical term for shingles?

A

Herpes zoster

51
Q

What does herpes zoster represent?

A

Herpes zoster represents reactivation of latent varicella

52
Q

What is the clinical presentation of chickenpox?

A

Is a highly contagious viral infection that causes acute fever and blistered rash, mainly in children

Easily spread from person to person by breathing in airborne respiratory droplets from an infected persons coughing or sneezing or through direct contact with the fluid from the open sores

Red macules, vesicules, pustules, crusts

53
Q

How does chickenpox spread from person to person?

A

Easily spread from person to person by breathing in airborne respiratory droplets from an infected persons coughing or sneezing or through direct contact with the fluid from the open sores

54
Q

What is the treatment of chickenpox?

A
  • Symptomatics
  • Calamine lotion
55
Q

What does VZV stand for?

A

Varicella-zoster virus (VZV)

56
Q

What is the clinical presentation of shingles?

A

Localised, blistering and painful rash caused by reactivation of varicella-zoster virus (VZV)

Characterised by dermatomal distribution

Blisters are confined to the VZV remains dormant in dorsal root ganglia nerve cells in the spine

57
Q

What are some complications of shingles?

A

Infection

Post-herpetic neuralgia

58
Q

What is neuralgia?

A

stabbing, burning, and often severe pain due to an irritated or damaged nerve

59
Q

What is the treatment of shingles?

A
  • Keep are clean to prevent infection
  • Pain relief
  • Rest
60
Q

What are viral warts caused by?

A

Human pipillomavirus

61
Q

What is the presentation of viral warts?

A
  • Pain
  • Discomfort

Hyperkeratonic papules, thick hyperkeratotic plaques (when grouped in clusters they are referred to as mosaic)

Most warts resolve spontaneously

62
Q

What are the leions like in viral warts?

A

Hyperkeratonic papules, thick hyperkeratotic plaques (when grouped in clusters they are referred to as mosaic)

63
Q

In what age group is viral warts most common?

A

Children

64
Q

What is the treatment of viral warts?

A
  • Salicylic acid
  • Cryotherapy
65
Q

When should patients with viral warts be referred to secondary therapy?

A

Referral to secondary care should happen when diagnostic uncertainty exists, patient is immunocompromised or warts are large or extensive

66
Q

What is molluscum contagiosum?

A

Common viral infection that mainly affects infants and young children

67
Q

Who does molluscum contagiosum mainly affect?

A

Infants and young children

68
Q

Where is molluscum contagiosum more prevalent?

A

Warm climates and overcrowded environments

69
Q

What is molluscum contagiosum caused by?

A

Poxvirus (poxviradae family)

70
Q

Describe the lesions due to molluscum contagiosum?

A

Lesions are firm, umbilicated perly papules with waxy surface, most common in skinfolds and genital region

71
Q

What is the treatment of molluscum contagiosum?

A
  • Curettage
  • Liquid nitrogen
  • Chemovesicants
72
Q

What are some examples of fungal skin infections?

A
  • Dermatophytosis
    • Ability to invade and multiply within keratinised tissue (hair, nail and skin)
  • Candidiasis
    • Opportunistic pathogenic fungi
    • Common member of human gut flora
  • Pityriasis versicolor
    • Normal flora of human skin
    • Cause non-inflammatory superficial mycosis
73
Q

What is pityriasis versicolor normal flora of?

A

Human skin

74
Q

What does pityriasis versicolor cause?

A

Non-inflammatory superficial mycosis

75
Q

What is mycosis?

A

Fungal infections of animals

76
Q

What is cadidiasis normal flora of?

A

Gut flora

77
Q

What is dermatophytosis?

A

An infection of the hair, skin, or nails caused by a dermatophyte, which is most commonly of the Trichophyton genus and less commonly of the Microsporum or Epidermophyton genera.

78
Q

What are different kinds of dermatophytosis?

A
  • Tinea corporis
    • Ringworm
  • Tinea cruris
    • Ringworm of the groin
  • Tinea capitis
    • Ringworm of the scalp
  • Tinea pedis
    • Ringworm of the foot
  • Tinea ungium
    • Ringworm of the nail
79
Q

What is tinea corporis?

A

Ringworm

80
Q

What is tinea cruris?

A

Ringworm of the groin

81
Q

What is tinea capitis?

A

Ringworm of the scalp

82
Q

What is tinea pedis?

A

Ringworm of the foot

83
Q

What is tinea umgium?

A

Ringworm of the nail

84
Q

What are some predisposising factors to mucocutaneous candida infections?

A
  • Diabetes
  • Occlusion
  • Hyperidrosis
  • Broad spectrum antibiotics
  • Immunosuppresion
85
Q

What are mucocutaneous candida infections caused by?

A

Candida albicans

86
Q

What is the presentation of mucocutaneous candida infections?

A
  • On the skin, erythematous patches often accompanied by satellites pastules
  • Intertriginous zones and diaper areas in infants
87
Q

What is the treatment of mucocutaneous candida infections?

A
  • Remove predisposing factors
  • Topical antifungals
  • Oral antifungals in some cases
88
Q

What is pityriasis versicolour?

A

Common fungal infection that causes small patches of skin to become scaly and discoloured

89
Q

Where is pityriasis verticolour often found on the body?

A

Sebum rich areas of the skin

90
Q

What is pityriasis versicolour caused by?

A

Malassezia species

91
Q

What is the predisposition to pityriasis versicolour?

A
  • High temperatures and humidity
  • Oil skin
  • Excessive sweating
92
Q

What are the lesions due to pityriasis versicolour like?

A

Multiple oval to round patches with mild scale

93
Q

What is the treatment of pityriasis versicolour?

A

Topical antimycotic (shampoos, creams)

94
Q

What are examples of infestations?

A
  • Scabies
  • Lice
95
Q

What is scabies?

A

Host-specific itch mite sarcoptes scabiei

96
Q

What is scabbies caused by?

A

Sarcoptes scabiei

97
Q

How is scabbies transmitted?

A

Via direct close contact

98
Q

What are some predisposing factors to scabbies?

A
  • Overcrowding
  • Delayed treatment
99
Q

What is required for the diagnosis of scabbies?

A
  • Skin scraping
  • Burrows visualisation
100
Q

What is the clinical presentation of scabbies?

A

Itch is characteristically more severe at night, causing disturbed sleep:

  • Affects trunk and limbs, sparing the scalp

Scabies burrows appear as 0.5-1.5cm grey irregular tracks in the web spaces between fingers, palms and wrists

101
Q

Describe scabbies burrows?

A

Scabies burrows appear as 0.5-1.5cm grey irregular tracks in the web spaces between fingers, palms and wrists

102
Q

What is the treatment of scabbies?

A
  • Antiscabietic topical treatment
  • Oral medicine might be needed in some cases
103
Q

What is head lice?

A

Itch and irritation in the scalp

Lice favour the nape of the neck and the skin behind ears

104
Q

Where do lice prefer to live?

A

Lice favour the nape of the neck and the skin behind ears

105
Q

What are nits?

A

Nits are the empty egg cases attached to hair that head lice hatch from

106
Q

What are nits observed as?

A

Adherent white grains on the hair shaft

107
Q

What is the treatment of head lice?

A
  • At least 2 applications of an insecticide and/or physical methods
  • Treat all members of the family at the same time
  • Inform the day care or school
108
Q

What is observed with head lice?

A

Nits are easier to see after the eggs have hatched, as adherent white grains on the hair shaft

Red-brown spots on skin are due to excreted digested blood