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Dermatology week 2 > Bacterial, fungal & parasitic Skin Infections > Flashcards

Bacterial, fungal & parasitic Skin Infections Flashcards

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1
Q

What is the gram stain and shape of staphylococcus

A

Gram +ve (purple) cocci in clusters

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2
Q

Can staphylococcus grow in both aerobic and anaerobic conditions ?

A

Yes - grows best in aerobic conditions

So can streptococcus (grows in anaerobic conditions if it has too)

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3
Q

What are the 2 most important classifications of staphloccocus and how are the differentiated?

A
  1. Staph.arueus (coagulase positive)
  2. Coagulase negative Staph - (Staph. epidermidis, Staph. saprophyticus etc.)
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4
Q

What is the coagulase appearance of staph.aureus and coagulase negative staph (e.g. staph.epidermis)?

A

Staph.aurues is coagulase positive which shows up as golden

Coagulase negative shows up as white

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5
Q

Name and describe another test which can be down to distinguish staph.aureus from all the other strains of staph ?

A

Latex agglutination - Staph.aureus tests positive all other staph are negative

Note:

Latex agglutination test is a clinical method to detect certain antigens or antibodies in a variety of bodily fluids such as blood, saliva, urine or cerebrospinal fluid. The sample to be tested is sent to the lab and where it mixed with latex beads coated with a specific antigen or antibody.

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6
Q

What strain of staph is the only one which is Novobiocin resistant ?

A

Staph. saprophyticus

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7
Q

Describe some of the main features of staph.aureus including - some of the common infections it causes and some of the toxins/enzymes it produces

A

Causes wound, skin, bone & joint infections

Some strains produce toxins:

  • Enterotoxin – food poisoning
  • SSSST – staph. scalded skin syndrome toxin
  • PVL – Panton Valentine Leukocidin

Produces enzymes, including coagulase, an enzyme that clots plasma hence coagulase positive

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8
Q

What is the first line antibiotic used to treat Staph.aureus?

If penicillin allergic then what would you give ?

A

Flucloxacillin

If penicillin allergic then give doxycycline

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9
Q

Are coagulase negative staph usually pathogenic ?

A

No usually just skin commensals but can cause infections

Note (staph.aureus is a common human pathogen)

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10
Q

What are the sort of infections that staph.epidermis is associated with ?

A

May cause infection in association with implanted artificial material, such as artificial joints, artificial heart valves, IV catheters

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11
Q

What infection is staph. saprophyticus associated with ?

A

Causes UTI in women of child bearing age

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12
Q

Describe the gram stain appearance of Streptococci

A

Gram +ve cocci in chains

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13
Q

How are the different types of streptoccoci classified ?

A

By haemolysis:

  • β(beta)-haemolytic (complete haemolysis)
  • α(alpha)-haemolytic (partial haemolyis)
  • γ(gamma) or non-haemolytic (no haemolysis)
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14
Q

Describe some of the features of beta-haemolytic strep - including

A

They are pathogenic organisms

Produce enzymes (toxins) - e.g. haemolysin (hence complete haemolysis) that damage tissues

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15
Q

How are beta-haemolytic strep further classified and what type of infections are the 2 main classifications associated with ?

A

Further classified by antigenic structure on surface (serological grouping)

  • Group A (throat, severe skin infections)
  • Group B (meningitis in neonates)
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16
Q

What are the two most important types of alpha-haemolytic strep ?

A

Strep. pneumoniae and Strep.viridans

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17
Q

What infections are strep.pneumoniae and strep.viridans associated with ?

A

Strep.penuomiae - commonest cause of pneumonia

Strep.viridans - commensals of mouth, throat, vagina - rarely cause infection

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18
Q

Give some examples of non-haemolytic strep (gamma) and the type of infection they are mainly associated with

A

Enterococcus species (E. faecalis, E. faecium)

  • Commensals of bowel
  • Common cause of UTI
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19
Q

What are some of the defence features of the skin against infection ?

A
  • Barrier
  • Sebum - fatty acids - inhibit bacterial growth
  • Competitive bacterial flora
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20
Q

Give a couple examples of the micro-organisms involved in the competitive bacterial flora of the skin

A
  • Staphylococcus epidermidis
  • Corynebacterium sp. (“diphtheroids”)
  • Proprionobacterium sp.
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21
Q

List some of the skin infections which staph.aureus can cause

A
  • Boils and Carbuncles
  • Other minor skin sepsis (infected cuts etc.)
  • Cellulitis
  • Infected eczema
  • Impetigo
  • Wound infection
  • Staphylococcal scalded skin syndrome
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22
Q

What bacterial complications can develop as a result of atopic dermatitis ?

A
  • People with atopic dermatitis also seem to have a reduced ability to fight against these common bacteria on the skin.
  • As a result, they frequently suffer from bacterial skin infections such as boils, folliculitis and impetigo.
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23
Q

What is impetigo?

A
  • A common acute superficial bacterial skin infection. Characterised by pustules and honey-coloured crusted erosions (‘school sores’).
  • It can be a primary infection or a complication of an existing skin condition such as eczema (in this case), scabies or insect bites
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24
Q

What is the main causative organisms of impetigo?

A
  • Staph. Aureus
  • Or sometimes Streptococcus pyogenes
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25
Q

In what age group is impetigo most common in ?

A

Children

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26
Q

Is impetigo contagious and if so how is it spread?

A

Yes very contagious:

  • Spread is by direct contact with discharges from the scabs of an infected person. The bacteria invade skin through minor abrasions and then spread to other sites by scratching. Infection is spread mainly by the hands, but indirect spread via toys, clothing, equipment and the environment may occur.
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27
Q

Where on the body does impetigo most commonly develop?

A
  • Face (in particular the peri-oral and peri-nasal areas), limbs esp hands and flexures (such as the axillae)
  • Can occur anywhere though
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28
Q

What are the 2 main types of impetigo?

A
  1. Non-bullous - most common
  2. Bullous
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29
Q

What are the clinical features of non-bullous impetigo ?

A
  • Vesciles or pustules initially develop & quickly rupture (so seldom seen clinically) releasing exudate which forms characteristic golden/brown crust
  • Usually asymptomatic but may have mild itch
  • Heals without scarring
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30
Q

What are the clinical features of bullous impetigo?

A
  • Lesions initially appear as flacid fluid filled vesicles & blisters (bullae) for 2-3days
  • Blisters then rupture leaving yellow (golden)/ brown crust
  • Heals without scarring
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31
Q

How is impetigo diagnosed ?

A
  • Clinically
  • Swabs for culutures & sensitivity considered in cases which are persistent despite treatment, recurrent, or widespread.
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32
Q

What is the treatment of localised lesions of imetigo?

A

1st line = topical fusidic acid

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33
Q

What is the treatment of extensive or severe impetigo?

A
  • 1st line = flucloxacillin
  • 2nd line = clarithromycin
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34
Q

What skin infection is shown here and what could be the causative organism ?

A

Infected eczema - could be caused by:

staph.aureus, Strep pyogenes (Group A strep)

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35
Q

List some of the bacterial skin infections which Strep pyogenes (Group A strep) is associated with ?

A
  • Infected eczema
  • Impetigo
  • Cellulitis
  • Erysipelas
  • Necrotising fasciitis – (N.B. may also be caused by mixed bacterial infection).
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36
Q

What is staphylococcal scalded skin syndrome (SSSS) & what is it caused by ?

A
  • It is an illness characterised by red blistering skin that looks like a burn or scald
  • SSSS is caused by the release of two exotoxins (epidermolytic toxins A and B) from toxigenic strains of the bacteria Staphylococcus aureus. These exotoxins causes splitting between desmosomes in granular layer
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37
Q

Who is most frequently affected by SSSS?

A

Children < 5 esp neonates

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38
Q

What are the clinical features of SSSS?

A
  • SSSS starts from a localised staphylococcal infection:
  • Initially - fever, irritability & widespread redness of the skin
  • Exstremly tender fluid-fluid blisters (bullae) then form. These blisters easily rupture leaving an area of skin that looks like a burn (rash)
  • Bullae are Nikolsky positive
  • Characteristics of the rash include; tissue paper like wrinkling of the skin, rash spreads to other part of the body, top layer of skin peeling off in sheets leaving an exposed moist red & tender area
  • Additional features - weakness & dehydration
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39
Q

How is SSSS diagnosed?

A

Usually clinically but swabs for C&S sent off & skin biopsy can be used to confirm it

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40
Q

What is the treatment of SSSS?

A
  • Hospital admission for - Topical fuisidic acid + IV flucloaxcillin
  • Also analgesia + Moist, bare areas should be lubricated with a bland emollient
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41
Q

What is cellulitis ?

A

It is an acute bacterial infection of the (lower) dermis and subcutaneous tissue.

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42
Q

What are the main causative organisms of cellulitis ?

A

Streptococcus pyogenes (two-thirds of cases) and Staphylococcus aureus (one third).

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43
Q

What are the risk factors for developing cellulitis ?

A
  • Previous episode(s) of cellulitis
  • Fissuring of toes or heels, eg due to athlete’s foot, tinea pedis or cracked heels
  • Venous disease,eg gravitational eczema, leg ulceration, and/or lymphoedema
  • Current or prior injury, eg trauma, surgical wounds, radiotherapy
  • Immunodeficiency, eg human immunodeficiency virus infection (HIV)
  • Immune suppressive medications
  • Diabetes
  • Chronic kidney disease
  • Chronic liver disease
  • Obesity
  • Pregnancy
  • Alcoholism
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44
Q

Where on the body is cellulitis most commonly seen?

A

More commonly seen in the lower limbs and usually affects one limb (bilateral leg cellulitis is very rare)

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45
Q

What are the clinical features of cellulitis ?

A
  • An acute onset of erythema, painful, hot, swollen, and tender skin, that spreads rapidly.
  • Usually an obvious skin break where the infecting organism may have entered e.g. a wound, macerated skin, fungal skin infection, an ulcer, or a concomitant skin disorder (such as atopic eczema).
  • Erythema may be diffuse or well-demarcated allowing it ot be marked with a pen in order to monitor progress.
  • Associated symptoms - may have Fever, malaise, nausea, shivering, and rigors
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46
Q

What is erysipelas ?

A

A superficial form of cellulitis it affects the upper dermis and extends into the superficial cutaneous lymphatics. It is also known as St Anthony’s fire due to the intense rash associated with it

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47
Q

What are the risk factors for developing erysipelas ?

A

Same as those for cellulitis

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48
Q

What is the main causative organism of erysipelas ?

A

Group A beta haemolytic streptococci (Streptococcus pyogenes)

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49
Q

What are the clinical features of erysipelas ?

A
  • Usually affects the lower limbs but may affect the face witha butterfly distribution
  • Rash occurs aburptly and is associated with fever
  • The affected skin has a very sharp, raised border.
  • It is bright red, firm and swollen. It may be finely dimpled (like an orange skin).
  • Cellulitis does not usually exhibit such marked swelling but shares other features with erysipelas, such as pain and increased warmth of affected skin.
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50
Q

What skin infection is shown here and what could of caused it ?

A

Erysipelas

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51
Q

How is cellulitis & erysipelas diagnosed?

A

Clinically some investigations may be done however to rule out other causes or confirm:

  • Inflam markers - ESR, CRP, WCC
  • Doppler U/S to help exlude DVT
  • Swab for culture if there is an open wound
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52
Q

What is the treatment of cellulitis & erysipelas ?

A
  • 1st line = Flucloxacillin
  • 2nd line = doxycyline if history or risk of MRSA
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53
Q

What is the treatment of facial cellulitis ?

A
  • Treat as per cellulitis guidance
  • HOWEVER if sinus/dental/mandibular source 1st line = co-amoxiclav or clindamycin
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54
Q

How are bacterial skin infections diagnosed ?

A

Swab of lesion if surface broken or swab Pus or tissue if deeper lesion. Take +/- blood cultures, if appropriate

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55
Q

What is the antibiotic treatment of choice for strep.pyogenes (Group A strep)?

A

Penicillin (flucloxacillin)

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56
Q

Define what Necrotising faciitis is

A

It is a very serious bacterial infection of the soft tissue and fascia. The bacteria multiply and release toxins and enzymes that result in thrombosis (clotting) in the blood vessels. The result is destruction of the soft tissues and fascia.

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57
Q

What are the clinical features of necrotising faciitis ?

A
  • Acute onset - usually within 24hrs of a minor injury
  • Painful, erythematous lesion develops
  • Area starts to swell and may show a purplish rash
  • Large dark marks form that turn into blisters filled with dark fluid
  • Wound starts to die and area becomes blackened (necrosis)
  • Oedema & surgical crepitus common
  • often presents as rapidly worsening cellulitis with pain out of keeping with physical features
  • extremely tender over infected tissue
  • Severe pain continues until necrosis/gangrene destroys peripheral nerves when the pain subsides
  • Associated flu-like symptoms, dehydration which eventually develops into the patient being very ill in shock
58
Q

Describe the treatment of necrotising faciitis

A
  • Requires immediate surgical debridement + IV antibiotics.
  • Antibiotic treatment depends on organisms isolated from tissue taken at operation

As there can be 2 types of necrotising faciitis:

  • Type 1 – mixed anaerobes & coliforms, usually post-abdominal surgery
  • Type II – Group A Strep infection
59
Q

Leg ulcers underlying problem is vascular so when would you need to treat leg ulcers with antibiotics and what is used ?

A

Only when the following answers to these questions are YES (i.e. signs of infection):

  1. Is there increased pain &/or exudate at the wound site?
  2. Is increased pain and exudate accompanied by cellulitis or pyrexia?

If answer to 1 is yes but 2 is no then tx = DO NOT SWAB & Use antimicrobial dressings (honey, iodine, Cutimed Sorbact or Flaminal)

If ans to both is yes then tx = 1st line flucloxacillin, 2nd line = doxycyline if penicillin allergy or history/risk of MRSA

60
Q

What is pitted keratolysis?

A

A descriptive title for a superficial bacterial skin infection that affects the soles of the feet, and less often, the palms of the hands.

61
Q

Who is at risk of developing pitted keratolysis ?

A

Occupations at risk include:

  • Farmers
  • Athletes
  • Sailors or fishermen
  • Industrial workers
  • Military personnel
  • Beauticians/Spa workers (pedicures & foot care)
62
Q

Where on the body is most commonly affected by pitted keratolysis ?

A
  • Primarily the soles of the feet
  • Less commonly the palms of hands may be affected
63
Q

What are the clinical features of pitted keratolysis ?

A
  • Very smelly feet
  • Areas of whiteish skin surface with punched-out pits
  • Usually asymptomatic otherwise
64
Q

How is pitted keratolysis diagnosed ?

A
  • Usually clinically, may be confirmed with skin biopsy
  • Skin scrappings & wood light exam usually also done to rule out fungal infection
65
Q

What is the treatment of pitted keratolysis ?

A

Topical antibiotics/antiseptics = topical fuisidic acid or Mupirocin

66
Q

What does tinea mean ?

A
  • Tinea is the name of a group of diseases caused by a fungus. Types of tinea include ringworm, athlete’s foot and jock itch.
  • Technically though means Ringworm - which is a fungal infection on the skin. It causes a rash that is often ring-shaped.
67
Q

What is a dermatophyte ?

A

A pathogenic fungus that grows on skin, mucous membranes, hair, nails, feathers, and other body surfaces, causing ringworm and related diseases.

68
Q

Match the Latin description of where the infection affects to its translation
Tinea capitis -
Tinea barbae -
Tinea corporis -
Tinea manuum -
Tinea unguium -
Tinea cruris -
Tinea pedis -

scalp, beard, body, hand, nails, groin, foot

A

Tinea capitis - scalp
Tinea barbae - beard
Tinea corporis - body
Tinea manuum - hand
Tinea unguium - nails
Tinea cruris - groin
Tinea pedis - foot
(athlete’s foot)

69
Q

Describe Dermatophyte pathogenesis

A
  1. Fungus enters abraded or soggy skin
  2. Hyphae spread in stratum corneum
  3. Infects keratinised tissues only (skin, hair, nails)
  4. Increased epidermal turnover causes scaling
  5. Inflammatory response provoked (dermis)
  6. Hair follicles and shafts invaded
  7. Lesion grows outward and heals in centre, giving a “ring” appearance
70
Q

Name each of the dermatophyte infections shown in the pics

(from top left to top right then bottom left to bottom right)

A
  1. Tinea capitis
  2. Tinea manuum
  3. Tinea corporis
  4. Tinea pedis(athletes foot)
  5. Tinea unguium
  6. Tinea cruris
71
Q

Who is commonly affected by dermatophyte infections?

A
  • Males - esp foot and groin ringworms
  • Also scalp ringworm mainly affects children
72
Q

What are the 3 main sources of dermatophyte infections ?

A

•Other infected humans**

–anthropophilic fungi

•Animals (cats, dogs, cattle)

–zoophilic fungi

•Soil (less common in UK)

–geophilic fungi

73
Q

List the 3 main causal organisms of dermatophyte skin infections

A

•Trichophyton rubrum (accounts for >70% of lab isolates)

–Human- human transmission

•Trichophyton mentagraphytes (next most common isolate (>20%)

–Human-human transmission

•Microsporum canis (occasional isolate)

– cats, dogs-humans

74
Q

What are the clinical features of tinea capitis?

A
  • Dry scaling & itching of the scalp
  • Single or multiple patches of alopecia - may result in permanent scarring & alopecia
  • +/- Black dots - hairs broken off at the scalp surface which is scaly
  • +/- Kerion - raised pustular, spongy/boggy mass which may form
75
Q

What is shown in this pic?

A

Kerion

76
Q

What is shown in this pic?

A

Tinea capatis

77
Q

What are the clinical features of tinea, corporis, cruris & manuum?

A
  • Single or multiple red/pink, flat or slightly raised annular (ring-shaped) patches
  • Patches have a red/pink scaly advancing edge with a clear central area → ring-shaped
  • Patches are itchy & may have pustules

i.e. on the body, groin and hands it presents very similar

78
Q

What is shown in the pic ?

A

Tinea corporis

79
Q

What is shown in the pic ?

A

Tinea cruris

80
Q

What are the clinical features of tinea pedis ?

A

May present in 1 of 3 ways:

  1. Itchy white or red, fissured scaling skin between the toes, esp 4th & 5th.
  2. Scale, erythema & hyperkeratosis, covering the sole & sides of the foot
  3. Small-medium sized blisters, usually affecting the inner aspect of the foot
81
Q

What is shown in this pic ?

A

Tinea pedis

82
Q

What are the clinical features of tinea unguium?

A
  • May affect 1 or more toenails & finger nails
  • Nail looks abnormal & is discoloured
  • White or yellow opaque streak
  • Scaling under nail (subungual keratosis)
  • End of nail lifts
  • Flaky white patches & pits
83
Q

What infection presents the same as tinea unguium and therefore accounts for a small proportion of thought to be fungal nail infections ?

A

Candida infeciton of the nail

84
Q

What is shown in the pic ?

A

Tinea unguium

85
Q

How are dermatophyte skin infections diagnosed ?

A
  • Scalp, body, groin, hand & foot dx = skin scrappings for M&C (wood lamp exammination is helpful)
  • For nail dx = nail clippings for M&C (wood lamp exam helpful)

Note:

  • Woods light (fluorescence) - Wood lamp examination is a diagnostic test in which the skin or hair is examined while exposed to the black light emitted by Wood lamp.
  • Skin scrapings, nail clippings, hair –Send to laboratory in a “Dermapak” for microscopy and culture
  • N.B. Culture takes 2 weeks +
86
Q

How should skin scrapping be taken ?

A

From the scaly edge of the lesion

87
Q

What organism is shown here ?

Hint it is the most common causal organism of dermatophyte skin infections

A

Trichophyton rubrum

88
Q

What is the treatment of tinea capatis ?

A

1st line = PO terbinafine + ketonazole shampoo

89
Q

What is the treatment tinea, corporis, cruris & manuum?

A

1st line = terbinafine cream for 14 days

90
Q

What is the treatment of tinea pedis ?

A

1st line = terbinafine cream for 7 days

91
Q

What is the treatment of tinea unguium ?

A
  • 1st line = PO terbinafine
  • 2nd line = itraconazole (or 1st if it turns out to be candida infection)
92
Q

What is pityriasis vesicolor?

A
  • A common yeast infection of the skin
  • It is characterised by discreet or confluent macules that have a fine powdery scale affecting the chest or back.
93
Q

What is pityriasis vesicolor caused by ?

A

Malassezia furfur

94
Q

What are the clinical features of pityriasis vesiocolor

A
  • Multiple round or oval macules and confluent patches
  • Patches are usually asymptomatic
  • Colour of lesions varies and can be fawn, pink, red, brown, or almost white — the surface of patches usually has a fine scale (which may be subtle).
95
Q

What is shown in this pic ?

A

Pityriasis vesicolor

96
Q

How is pityriasis vesicolor diagnosed ?

A

Clinically - skin scrappings only required if it doesnt respond to initial treatment

97
Q

What is the treatment of pityriasis vesicolor ?

A
  • 1st line (if extensive area involved) = ketoconazole shampoo
  • 1st line (if small area involved) = Imidazole creams (such as clotrimazole [preferred in pregnancy], econazole, or ketoconazole)
98
Q

What is candida?

A

A yeast-like fungus which is part of the normal commensal flora of the human gastrointestinal tract and the vagina (in 13% of women)

99
Q

What is candidiasis and list the different types of it ?

A

This is infection caused by candida it usually occurs when mucosal barriers are disrupted or if the host’s defences are lowered. There are a range of different candidiasis infections:

  • Intertrigo (skin fold infections) — this most commonly occurs in the groin, under the breasts, and the axillae. It may also affect antecubital fossae; umbilical, perineal, or interdigital areas; neck creases; and folds of the eyelids.
  • Oral candidiasis (infection of the oral mucosa)
  • Genital infections including; Vulvovaginal candidiasis & Balanitis (inflammation of the glans penis) (covered in O&G)
  • Napkin dermatitis (nappy or diaper rash)
  • Chronic paronychia (nail fold infection)
  • Onychomycosis (nail plate infection)
100
Q

What is the main causative organism of candidiasis ?

A

C.albicans

101
Q

What are the clinical features of oral candidiasis ?

A
  • Pseudomembranous oral candidiasis (oral thrush) presents with patches of curd-like, white or yellowish plaques that can occur anywhere in the mouth. When removed show underlying red base.
  • Chronic candidiasis: atrophic or hyperplastic plaques
  • Median rhomboid glossitis: diamond-shaped inflammation at the back of the tongue
  • Angular cheilitis (fissured oral commissures) - inflam of corners of mouth with skin breakdown & crusting
102
Q

What is shown in the pic?

A

Angular cheilitis

103
Q

What are the clinical features of intertrigo (skin folds) candidiasis ?

A

Erythematous and macerated plaques with peripheral scaling. There are often associated superficial satellite papules or pustules. Occurs in skin folds, common areas include:

  • Foot (athletes foot)
  • Web spaces of hands esp in gardeners & housewifes
  • Under the breast (submammary) or inguinal cleft
  • Nappy rash
104
Q

How is candidiasis diagnosed ?

A
  • Swabs for M&C if secondary bacterial infection suspected, the person is immunocompromised or diagnosis is uncertain
  • Otherwise diagnosed clinically
105
Q

What is the treatment of candidiasis ?

A

Oral:

  • 1st line (if mild, localised) = miconazole gel, 2nd line = nystatin suspension
  • 1st line (if extensive or severe) = PO fluconazole

Skin:

  • 1st line = clotrimazole cream

Nail:

  • 1st line = PO itraconazole
106
Q

What is scabies & the causative organisms?

A
  • A very itchy rash caused by a parasitic mite that burrows in the skin surface.
  • Sarcoptes scabiei cause it
107
Q

How is scabies spread and is it contagious ?

A
  • Spread via direct skin to skin contact
  • It is a contagious disease and may spread extensivley in e.g. residential homes
108
Q

What are the clinical features of scabies ?

A
  • A very itchy rash (worse at night)
  • Linear burrows best seen on the side of fingers, interdigital webs and flexor aspects of the wrist
  • Vesicles, papules & rubbery nodules may also be seen
  • secondary features are seen due to scratching: excoriation, infection
109
Q

What is shown in this pic ?

A

Burrows seen in scabies

110
Q

How is diagnosis of scabies confirmed ?

A

Ink burrow test and/or microscopy of skin scrapings

111
Q

How long is the incubation period of scabies ?

A

Up to 6 weeks

112
Q

What is the treatment of scabies?

A
  • 1st line = permethrin cream 5% + steroid or crotamiton cream for itch
  • 2nd line = malathion 0.5% lotion is second-line
113
Q

What does pediculosis mean ?

A

Lice

114
Q

Appreciate this:

Head lice are small insects that live only on humans, they feed on our blood. Eggs are grey or brown and about the size of a pinhead. The eggs are glued to the hair, close to the scalp and hatch in 7 to 10 days. Nits are the empty egg shells and are white and shiny. They are found further along the hair shaft as they grow out.

A
115
Q

How is head lice spread & who is it common in?

A
  • Direct head to head contact - they cannot jump swim or fly!
  • Common in children esp girls
116
Q

What are the clinical features of head lice ?

A
  • When newly infected, cases have no symptoms until 2-3 weeks after infection
  • Primary symptoms are itching & scratching (of the head or area affected)
117
Q

Match the follow types of lice infections to the area they affect:

  • Pediculus capitis
  • Pediculus corporis (Vagabond’s disease)
  • Phthirus pubis

Head louse, Pubic louse, Body louse

A
  • Pediculus capitis - Head louse
  • Pediculus corporis (Vagabond’s disease) - Body louse
  • Phthirus pubis - Pubic louse
118
Q

How is lice infections diagnosed ?

A

Fine-toothed combing of wet or dry hair

119
Q

What is the treatment for lice infections and what is the main symptom of lice infections ?

A

Head lice:

  • 1st line = Dimeticone or malathion lotion

Crabs (pubic lice):

  • 1st line = Permethrin 5% cream or malathion lotion
120
Q

Due to patients with skin infections, they often shed huge numbers of skin scales & associated bacteria into the environment what precautions must be taken to help prevent spread ?

A

Gloves and plastic aprons (“contact precautions”) required for dressings changes

Patients who need single room isolation and contact precautions:

  • Patients with Group A Strep infection
  • Patients with (MRSA) infection
  • Patients with Scabies (N.B. long sleeved gowns also required for Norwegian scabies)
121
Q

What is folliculitis ?

A
  • It is the name given to a group of skin conditions in which there are inflamed hair follicles. The result is a tender red spot, often with a surface pustule.
  • Acne and its variants are also types of folliculitis.
122
Q

What causes folliculitis ?

A

Folliculitis can be due to infection, occlusion (blockage), irritation e.g. ingrown hairs and various skin diseases (e.g. acne and its variants)

123
Q

What is the most common form of folliculitis ?

A

Bacterial

124
Q

What is the main causative organism of bacterial folliculitis ?

A

Staph. Aureus

125
Q

Where on the body does folliculitis affect?

A

It can affect anywhere there are hairs, including chest, back, buttocks, arms and legs.

126
Q

What are the 2 forms of bacterial folliculitis?

A
  1. Superficial
  2. Deep (furnunculosis) = involve the whole hair follicle
127
Q

What are the clinical features of superficial bacterial folliculitis ?

A
  • One or more follicular pustules.
  • They may be itchy or mildly sore.
  • Heal without scarring
128
Q

What are the 2 descriptive types of deep bacterial folliculitis (furnuculosis)?

A
  1. Boil – single hair follicle
  2. Carbuncle – contiguous hair follicles (collection of boils)
129
Q

What are the clinical features of a boil?

A
  • Boils initially appear as firm, tender, erythematous nodules, which after several days enlarge and become painful and fluctuant
  • Careful inspection reveals that the boil is centred on a hair follicle.
  • May rupture spontaneously, draining pus or necrotic material.
  • Cellulitis may also occur
  • Boils & carbuncles resolve leaving a scar
130
Q

What are the clinical features of a carbuncle ?

A

Features of a boil + multiple heads (several follicles and has multiple draining sinuses)

131
Q

How is folliculitis diagnosed?

A

Clinically

132
Q

What is the treatment of bacterial folliculitis ?

A

PO flucloxacillin + apply moist heat + incision & drainage (if fluctuant boil/carbuncle)

133
Q

What is a paronychia ?

A
  • It is the inflammation of the folds of tissue surrounding the nail
  • It can be acute (< 6 weeks) or chronic (persisting > 6 weeks)
134
Q

Define acute paronychia

A

It is is a localized, superficial infection or abscess of the lateral and proximal skin fold around a nail (perionychium), causing painful swelling

135
Q

What are the main causes of acute paronychia ?

A
  • Usually staph.aureus
  • Sometimes Streptococcus pyogenes or Pseudomonas
  • Herpes simplex has also been known to cause it
136
Q

What are the clinical features of acute paronychia ?

A
  • Usually affects one finger (can also affect toes)
  • The lateral and/or proximal nail folds are red, tender, and swollen, and a visible collection of pus may be present.
  • In more severe cases abscess formation with fluctuance may occur
137
Q

How is acute paronychia diagnosed?

A

Clinically

138
Q

What is the treatment of acute paronychia ?

A
  • If minor, localised infection consider topical antibiotics (fusidic acid)
  • If fluctuant pus collection or abscess tx = incision + drainage
  • Give PO flucloxacillin if incision and drainage Is not required.or was performed, but the person has signs of cellulitis or fever
139
Q

What is the typical clinical features of insect bites/stings ?

A
  • Ranges from small papules to large bullae
  • Lesions usually itchy & may be painful
  • Pattern of lesions is usually linear & grouped
140
Q

What is the treatment of insect bites ?

A

Dermatology week 2 (22 decks)

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