Skin Infections - Bacterial, Viral & Fungal Flashcards
(171 cards)
1
Q
What is impetigo and what does it look like?
A
it is a common acute superficial bacterial infection
it is characterised by pustules and honey-coloured crusted erosions
“looks like cornflakes”
2
Q
Who is most commonly affected by impetigo?
When is the peak onset?
A
- most common in children (especially boys)
- prevalent worldwide, but more in developing countries
- peak onset is during the summer
3
Q
What parts of the body are usually affected by impetigo?
A
exposed areas (like the face & hands) are mainly affected
the trunk and perineum can also be involved
4
Q
How do the plaques change and develop as impetigo progresses?
A
single or multiple areas can be affected by irritable superficial plaques
these are irregular in shape and size
the plaques will extend as they heal to form annular or arcuate lesions
5
Q
What other symptoms may someone with impetigo have?
A
presence of other symptoms is rare, but may include:
- lymphadenopathy
- mild fever
- malaise
6
Q
What are the risk factors for impetigo?
A
- atopic eczema
- scabies
- skin trauma
- chickenpox
- insect bites
- wounds
- burns
- dermatitis
7
Q
What causes impetigo and its subtype, ecthyma?
A
it is most commonly caused by Staphylococcus aureus
ecthyma is caused by Streptococcus pyogenes
8
Q
What are the 3 different types of impetigo?
A
- non-bullous
- ecthyma
- bullous
9
Q
What causes non-bullous impetigo?
How does it present?
A
it is caused by Staph / Strep invading a minor trauma site
this forms a pink macule, which progresses to a vesicle/pustule and then into a crusted erosion
10
Q
What is the usual treatment for non-bullous impetigo?
A
it will usually resolve in 2-4 weeks without any treatment
11
Q
What is the main cause of ecthyma?
How does this present?
A
Main cause of ecthyma is Streptococcus pyogenes
it starts as non-bullous impetigo but progresses to a punched-out necrotic ulcer
this is slow healing and will leave a scar
12
Q
What causes bullous impetigo?
A
Staphylococcus aureus
Staph exfoliative proteins will infect intact skin by cleaving off the epidermis
13
Q
How does bullous impetigo present?
A
it starts off with small vesicles which progress into flaccid transparent bullae
it will heal without scarring
14
Q
How is impetigo diagnosed?
A
it is diagnosed clinically
bacterial swabs are taken to confirm the diagnosis
15
Q
What treatments are given for impetigo?
A
- the wound is cleaned with antiseptic
- the affected areas are covered
- if it is extensive, oral antibiotics (flucloxacillin) are given
16
Q
What advice is given to patients with impetigo?
A
- avoid contact with others - physical & towels/flannels etc.
- children must avoid school until crust dries
- wash daily with antibacterial soap and identify the source of infection to avoid re-infection
17
Q
What are the 3 potential complications of impetigo?
A
- soft tissue infection (e.g. cellulitis) with risk of subsequent bacteraemia
- staphylococcal scalded skin syndrome
- post-streptococcal glomerulonephritis
18
Q
What causes staphylococcal scalded skin syndrome?
A
- caused by the release of two exotoxins (epidermolytic toxins A & B) from toxigenic strains of S. aureus
* the toxins bind to Desmoglein 1 within desmosomes and break it up
* desmosomes within skin cells are responsible for adhering to the adjacent cell
* without Desmoglein 1, the skin cells become unstuck
19
Q
How does staphylococcal scalded skin syndrome present?
A
red blistering skin that appears like a burn or scald
it is a dermatological emergency
20
Q
What are cellulitis & erysipelas?
A
a spreading bacterial infection of the skin that involves deep subcutaenous tissue
21
Q
What is the difference between cellulitis and erysipelas?
A
erysipelas is an acute, superficial form
this only involves the dermis and upper subcutaenous tissue
22
Q
Who is affected by cellulitis / erysipelas?
What is it often falsely attributed to?
A
it affects all races and ages
it is often falsely attributed to unseen spider bites
23
Q
What is done to monitor progression of cellulitis / erysipelas in clinic?
A
it involves spreading erythema
often the erythema is drawn around to see whether it continues to spread after treatment has been given
24
Q
How is erysipelas distinguished from cellulitis in clinic?
A
In erysipelas there is a well-defined, red, raised border
25
What are the general clinical features of someone with cellulitis or erysipelas?
* most commonly on the **lower limbs**
* mostly **unilateral**
* **local inflammatory signs** are present (tumour, rubor, calor, dolor)
* patient is **systemically unwell**
* fever, malaise, rigors (particularly in erysipelas)
26
What are the risk factors for cellulitis / erysipelas?
* previous episodes of cellulitis
* fissures in the toes/heels (e.g. athletes foot)
* venous disease
* current or prior injury (trauma / surgery)
* immunodeficiency
* obesity & diabetes
* pregnancy
27
What are the causes of cellulitis?
* Staphylococcus aureus
* Streptococcus pyogenes
28
How is cellulitis / erysipelas diagnosed?
diagnosis is largely clinical
blood culture or wound swabs are taken to identify the causative organism and help with antibiotic choice
29
What are the treatments for cellulitis / erysipelas?
**antibiotics:**
* Flucloxacillin
* Benzylpenicillin
**supportive care:**
* rest
* elevation of lower limb
* sterile dressings
* analgesia
30
What are the potential complications of cellulitis?
* local necrosis
* abscess formation
* septicaemia
31
What condition can present similarly to cellulitis?
**necrotising fasciitis**
this affects the skin, subcutaenous tissue, fascia and muscle
32
What are the main differences between necrotising fasciitis and cellulitis?
* oedema may extend beyond the area of erythema (may blister or have bullae)
* crepitus on palpation due to soft tissue gas
* pain is more extreme than cellulitis
* more rapid progression
* patient is more systemically unwell
33
What is meant by folliculitis?
a group of skin conditions where **hair follicles become inflamed**
(e.g. acne is a type of folliculitis)
34
What are the general clinical features of folliculitis?
What does it look like?
* **tender red spots**, often with **surface pustule**
* can be **superficial or deep**
* affects **anywhere** on the body where **there is hair**
* chest
* back
* buttocks
* arms and legs
35
What are the 2 main variants of folliculitis?
* acne variants
* buttock folliculitis
36
What are the 4 different acne variants of folliculitis?
* acne vulgaris
* rosacea
* nodulocystic acne
* scalp folliculitis
37
Who tends to be affected by buttock folliculitis?
* this is usually bacterial
* it is common and non-specific
* it affects males and females equally
38
What are the bacterial causes of folliculitis?
the main causative organism is ***Staphylococcus aureus***
"Spa pool folliculitis", which is common in poorly chlorinated warm water, is caused by ***Pseudomonas aeruginosa***
39
What are other infective causes of folliculitis?
**Viral:**
* herpes simplex
* herpes zoster
**Yeast / Fungi:**
* tinea capitis
* candida
**Infestations:**
* hair follicle mites
* scabies
40
What are other non-infective causes of folliculitis?
* **occlusion (blockage)** of hair follicles due to occlusive topical agents
* **irritation** due to regrowth from shaving, waxing, etc.
41
How is folliculitis diagnosed?
it is diagnosed clinically
bacterial swabs can be taken to confirm the causative organism
42
What are the treatments for folliculitis?
* careful hygiene & antiseptic cleanser
**Bacterial:**
* topical / oral antibiotics - e.g. **tetracycline**
**Viral:**
* **aciclovir**
**Yeast / fungi:**
* topical / oral antifungal
43
What is intertrigo?
Who is affected?
this is a **rash** in the **flexures / body folds**
it may affect one or multiple sites
it can affect males and females of any age
44
Which parts of the body tend to be affected by intertrigo?
intertrigo describes a rash in the **flexures / body folds**, such as:
* behind the ears
* axillae
* groin
* buttocks
* finger / toe webs
45
What are the general clinical features of intertrigo?
* exact appearance and behaviour depends on cause
* skin is **inflamed and uncomfortable**
* skin may become **moist**, leading to **fissures and peeling**
46
What are the 3 main risk factors for intertrigo?
* obesity
* genetic tendency
* hyperhidrosis (excessive sweating)
47
What are the reasons why intertrigo develops in body flexures / folds?
* flexural skin has a **high surface temperature**
* **moisture is prevented from evaporating** due to skin folds
* friction from movement of folded skin can cause chafing
* bacteria and/or yeast multiply in **warm, moist settings**
48
What other skin infections / conditions can cause intertrigo?
**skin infections:**
* thrush
* tinea infections
**skin conditions:**
* flexural psoriasis
* various dermatitises
49
What are the 2 different types of intertrigo?
**Infectious** and **Inflammatory**
Intertrigo can then be **acute**, **relapsing** or **chronic** (\>6 weeks)
50
What are the distinguishing features of infectious and inflammatory intertrigo?
**Infectious:**
* tends to be unilateral
* tends to be asymmetrical
**Inflammatory:**
* tends to be bilateral
* tends to be found in the armpits, groin, under breasts & abdominal folds
51
How is intertrigo diagnosed?
**bacterial swabs** are taken to identify causative organism
**skin biopsies** are performed if intertrigo is unusual or not responding to conventional treatments
52
What are the treatments for intertrigo?
* antiperspirants
* topical/oral antibiotics or antifungals (depending on cause)
**for inflammation:**
* low potency topical steroids - e.g. **hydrocortisone**
* calcineurin inhibitors - e.g. **tacrolimus**
53
What are the potential complications of intertrigo?
* **soft tissue infection** (e.g. cellulitis) with risk of subsequent bacteraemia
* **staphylococcal scalded skin syndrome**
* **post-streptococcal glomerulonephritis**
54
What age group is usually affected by chickenpox?
it is a highly contagious disease that mostly occurs in **children under 10**
once an individual has had it once, it is unlikely to occur again
55
What are the general clinical features of children presenting with chickenpox?
* **itchy red papules and vesicles**
* occurring on the **stomach, back, face** and can spread to other body parts
* blisters can be in the mouth
* pattern varies between children in both frequency and location
56
What systemic symptoms are associated with chickenpox?
* fever
* headache
* diarrhoea and vomiting
57
How does adult infection of chickenpox tend to present?
they develop prodromal symptoms 48 hours before the rash, including:
* fever
* malaise
* headache
* loss of appetite
* abdominal pain
adult infection is much more severe and can be life threatening
58
What are the risk factors associated with chickenpox?
* children under 10
* immunocompromised
* it affects all races and genders equally
59
What causes chickenpox?
What is the % chance of developing infection if patient is not immune?
it is caused by **varicella zoster virus (VSV)** which is Herpes type 3
it is contracted through contact with **fluid from open sores** but can be **airborne**
if not immune, a person has a 70-80% chance of infection if exposed in early stages
60
For how long is chickenpox contagious?
it is contagious **1-2 days before the rash appears** until the **blisters have scabbed over** (can be 5-10 days)
61
How long can it take to develop chickenpox after coming into contact with it?
it can take **10-21 days** after contact to develop chickenpox
children should stay away from school during this contagious period
62
Who should avoid visiting people who have had chickenpox contact?
**immunocompromised individuals** and **pregnant women** should avoid visiting those with chickenpox contact due to risk of complications
63
How long does it take for chickenpox blisters to clear up?
What may scars look like?
blisters clear up naturally in **1-3 weeks**
they may leave scars that are often **hypertrophic** (thickened) and **anetodermic** (depressed)
these are more prominent when bacterial infection occurs
64
What is the treatment for immunocompromised patients with chickenpox?
IV aciclovir
65
What are the supportive treatments available for children with chickenpox?
* trimming fingernails to minimise scratching
* warm baths and using moisturiser
* **paracetamol** for fever
* **oral antihistamines** may help with itching
66
What are the possible complications of chickenpox in children?
In children, chickenpox is usually uncomplicated and self-limiting but...
* **secondary bacterial infection** caused by scratching
* **dehydration** from diarrhoea & vomiting
* **viral pneumonia**
67
What are potential complications of chickenpox in immunocompromised and adult patients?
* disseminated varicella infection
* CNS complications
* Reye's
* Guillain-Barre
* encephalitis
* Thrombocytopenia & purpura
68
What is meant by disseminated varicella infection?
this is a generalised eruption of more than 10-12 extradermatomal vesicles occurring 7-14 days after the onset of classic dermatomal herpes zoster (shingles)
it is clinically indistinguishable from chickenpox but has a high morbidity
69
What is Reye syndrom?
What are typical symptoms?
it is a rapidly worsening brain disease that is also associated with liver toxicity
* vomiting
* personality changes
* confusion
* seizures
* loss of consciousness
20-40% of those affected will die, and the majority left will have a significant degree of brain damage
70
What is Guillain-Barré syndrome?
What are the initial symptoms?
it is a **rapid-onset muscle weakness** caused by the immune system damaging the **peripheral nervous system** (and their myelin sheath)
typically both sides are involved and initial symptoms include:
* changes in sensation or pain often in the back
* muscle weakness, beginning in the feet and hands
* muscle weakness then spreads to the arms & upper body
71
How long does it take for symptoms to begin in Guillain-Barré syndrome?
the symptoms develop over hours to a few weeks
72
Why can Guillain-Barré syndrome be life-threatening during the acute phase?
* 15% of people will develop **weakness of the breathing muscles** and will require mechanical ventilation
* some people are affected by changes in the autonomic nervous system, which can lead to dangerous abnormalities in **heart rate** and **blood pressure**
73
What is immune thrombocytopenic purpura (ITP)?
What does it look like?
it is a type of thrombocytopenic purpura defined as an **isolated low platelet count** with a **normal bone marrow** in the absence of other causes of low platelets
it causes a characteristic **red or purple bruise-like rash** and **increased tendency to bruise**
74
What are the potential complications of chickenpox in pregnancy?
* viral pneumonia
* premature labour
75
What can VZV present with later in life after having chickenpox?
following infections of VZV, the virus remains dormant and can re-present in later life
this presents as **herpes zoster** (shingles)
76
What does herpes zoster (shingles) look like?
it is a localised, painful rash caused by reactivation of VZV
this is usually within a specific dermatome
77
What are the initial signs of herpes zoster (shingles) before the rash develops?
* first sign is **severe pain** in **one sensory nerve distribution**
* there is also fever, headache and lymphadenopathy in the affected area
78
When do blisters develop in shingles?
What do they tend to look like and where tends to be affected?
* after **1-3 days** a **blistering rash** appears in the same area of skin in which pain was felt
* begins as red papules and progresses to **blisters that crust over**
* commonly affects the **chest, neck, forehead & lumbar/sacral regions**
79
What are the risk factors and triggers for development of herpes zoster (shingles)?
* most common in adults, especially the **elderly** & **immunocompromised**
**Triggers:**
* nerve pressure
* radiotherapy at the level of the nerve root
* spinal surgery
* infection
80
What causes herpes zoster (shingles)?
* caused by **herpes zoster virus** & **reactivation of VZV**
* anyone who has previously had chickenpox can get shingles
* VZV remains **dormant in dorsal root ganglia** for years
* when reactivated, it **migrates down sensory nerves to the skin** and causes symptoms
81
What is recovery time for shingles in uncomplicated cases?
What treatment may be given?
* recovery is **2-3 weeks** for children/young adults
* recovery is **3-4 weeks** in older patients
* antiviral treatment with **_aciclovir_** can reduce pain and symptom duration
82
What advice is given to patients with shingles for management of acute symptoms?
* pain relief and rest
* using vaseline to protect the rash
* oral antibiotics may be given for secondary bacterial infection
* shingles is infectious to people who have not had chickenpox, so try and avoid these
83
What is the main complication of herpes zoster (shingles)?
involvement of several dermatomes
deep blisters, with prolonged healing and scarring
84
How many patients with herpes zoster experience muscle weakness?
What is recovery like for this?
5% of patients with shingles experience muscle weakness
this is most commonly **Ramsay-Hunt syndrome** - a **facial nerve palsy**
there is 50% chance of recovery with most patients seeing some improvement
85
What organs can be infected as a complication of shingles?
* GI tract
* lungs
* brain (encephalitis)
86
What can happen if shingles infection occurs during pregnancy?
infection is rare in pregnancy but can harm the foetus
a foetus infected with chickenpox may develop herpes zoster as an infant
87
What is post-herpetic neuralgia?
Who is most commonly affected?
a complication of shingles in which there is **persistence/re-occurance of pain** in the **same area** more than **1 month after the onset** of herpes zoster
this is more common in **facial infections** and in **older patients**
88
What is herpes simplex?
Who tends to be affected?
this is a common infection referred to as "cold sores" and "fever blisters"
it affects most people during their lives
89
What are the different types of herpes simplex and which one is more symptomatic?
Type 1 and Type 2
Type 2 is often more symptomatic than Type 1
90
How does Type 1 herpes simplex most commonly present?
it most commonly presents as **gingivostomatitis** in children aged 1-5
91
How does gingivostomitis present?
* fever and restlessness
* excessive dribbling and bad breath
* swollen/red/bleeding gums and painful eating
* white vesicles & yellow ulcers on the tongue, throat, palette and inside the cheeks
* lymphadenopathy
92
What are the risk factors for herpes simplex?
* mainly affects infants and young children
* in less developed countries, nearly all children under 5 are affected
93
What is the main difference between type 1 and type 2 herpes simplex infection?
**Type 1:**
* tends to be involved in ***oral and facial infections***
**Type 2:**
* tends to be involved in ***genital and rectal infections***
* often transmitted sexually
however, either virus can affect other areas of skin/mucous membranes
94
95
What causes herpes simplex infection?
* virus is spread by **direct or indirect contact**
* it remains **dormant in dorsal root nerves**, where it can be reactivated
* the virus can be transferred to new skin sites by the patient during an attack
96
How does Type 2 herpes simplex usually present?
it usually results in **genital herpes** after onset of sexual activity
this results in painful vesicles, ulcers, redness and swelling for 2-3 weeks
97
What are the symptoms of genital herpes in males and females?
**in males:**
* tends to affect the glans, foreskin and shaft
* anal herpes is more common in men who have sex with men
**in females:**
* tends to affect the vulva and vagina
* often painful to urinate
* cervical infection may lead to severe ulcers
98
Can recurrence occur in herpes simplex?
yes
recurrence may never happen unless viral immunity is not sufficient
Type 2 HSV recurrence is much more common than Type 1
99
What are the triggers for recurrence of herpes simplex?
* minor trauma
* UV radiation and sun exposure
* hormones (e.g. prior to menstruation)
* emotional stress
* being unwell with another illness
infection usually returns to the same site as the primary infection
100
What are the treatments for herpes simplex?
* uncomplicated eruptions are **self-limiting**
* antiviral drugs (**aciclovir**) are used for severe infection
101
What are the potential complications of herpes simplex infection?
* eye infection - swollen eyelids & conjunctiva, can lead to corneal ulceration
* throat infection - painful & affects swallowing
* erythema multiforme
* eczema herpeticum
* disseminated / widespread infection - serious in immunocompromised patients e.g. HIV
102
How does erythema multiforme present?
targetoid lesions with central blisters
these are symmetrical plaques on the hands, forearms, feet and lower legs
103
104
What is eczema herpeticum?
this is a complication of HSV that can occur in patients with underlying skin conditions, such as eczema
it is a **severe and widespread** infection characterised by **fever** and **clusters of itchy blisters** or **punched out erosions**
105
What % of people with HIV experience a skin condition?
* 18-46% of HIV patients experience a **pruritic papular eruption**
* acute HIV infection syndrome has some skin manifestations
* other skin diseases are more common in HIV patients
106
How many people with HIV will experience acute HIV infection syndrome?
* **40-90%** of those infected with HIV will experience acute HIV infection syndrome during the **first few weeks following exposure**
* people are especially infectious during this period
107
What are the general symptoms and dermatological symptoms associated with acute HIV infection syndrome?
**general symptoms:**
* fever & malaise
* loss of appetite & GI symptoms
* lymphadenopathy
* sore muscles / joints
**dermatological symptoms:**
* ***erythematous maculopapular rash*** that is symmetrical & involves the face, palms and soles
* ***mucocutaenous ulceration***
108
What is the treatment for someone with acute HIV infection syndrome?
they should be started on **antiretroviral treatment (ARV)** immediately
the symptoms tend to settle within a few days to weeks
109
What is the most common rash seen in HIV?
What causes it?
**pruritic papular eruption of HIV**
this is a form of prurigo
there is no identified cause and it is a diagnosis of exclusion (when all other causes have been discounted)
110
What is meant by "prurigo"?
prurigo describes intensely itchy spots
111
What are the symptoms of pruritic papular eruption of HIV?
* intense itching
* discrete scratched red bumps
* symmetrical
* diffuse rash
* most commonly affecting the extremities and trunk
* no mucosal, palmar or webbing involvement
112
What are the treatments for pruritic papular eruption of HIV?
* topical steroids, emollients & antihistamines
* if these are not effective, then phototherapy is used
113
What are viral skin conditions associated with HIV?
* HSV and VSV
* molluscum contagiosum
* human papillomavirus
* oral hairy leukoplasia due to EBV
114
What fungal skin infections are associated with HIV?
* tinea
* candidiasis
* cryptococcosis
* pityrosporum
* pityriasis versicolor
* pneumocystosis
115
What bacterial skin conditions are associated with HIV?
* cellulitis. ecthyma, impetigo & folliculitis (Strep)
* syphilis
* atypical mycobacteria
116
What infestations of the skin are associated with HIV?
* leishmaniasis
* scabies
117
What inflammatory skin conditions are associated with HIV?
* seborrhoeic dermatitis
* psoriasis
* eczema
* pruritic papular eruption
* granuloma annulare
118
What malignancies are associated with HIV?
* Kaposi's sarcoma
* B- & T-cell lymphoma
* melanoma
* squamous cell carcinoma / basal cell carcinoma
119
What is shown in these images?
**viral warts**
these are very common non-cancerous growths
120
What are the risk factors for viral warts?
* more common in **school-aged children**
* **eczema** - due to the defective skin barrier
* **immunosuppressed individuals** - warts rarely disappear in these patients
121
What virus causes viral warts?
How do they develop?
**human papilloma virus (HPV)**
infection occurs in the superficial epidermis, causing **keratinocyte proliferation** and **hyperkeratosis**
(hyperkeratosis = thickening of the outer layer of the skin)
122
How are viral warts spread?
What is their incubation period?
they are spread by **skin-to-skin contact** or **auto-inoculation** (if scratched, virus can spread to another area)
the incubation period can be **up to 12 months**
123
How do viral warts typically present?
they present as a **hard surface** with a **black dot** in the middle of each scale
this black dot is a thrombosed capillary blood vessel
124
What are the 5 different types of viral warts?
* common warts
* plantar warts (verrucas)
* plane warts
* filiform warts
* mucosal warts
125
What do common warts look like?
Where do they tend to be found?
* **papules with a hyperkeratotic, rough surface**
* diameter of 1mm to 1cm
* found on the back of the fingers / toes, around the nails & on the knees
* "Butcher's warts" have a cauliflower-like appearance
126
How do plantar warts (verrucas) present?
* wart occurs on the sole of the foot or toes
* they are tender and inward growing
* less painful than other warts
127
What do plane warts look like and where do they occur?
* these have a **flat surface** & are often **numerous**
* tend to be found on the **hands, face and shins**
* they are spread by **shaving / scratching**, leading to them appearing in a **linear distribution**
128
What do filiform warts look like and where do they tend to be found?
* they have long, narrow projections that extend 1-2mm from the skin surface
* they don't often form clusters
* most commonly found on the face
129
Where are mucosal warts found?
on the lips and the inside of the cheeks
130
Why are tests and treatments not always needed for viral warts?
tests are rarely needed as warts have a characteristic appearance
many warts are not treated as treatment can be very uncomfortable
small warts that are not causing pain can be left and sometimes will disappear
131
What are the 3 different treatment methods used for treating viral warts?
* topical treatment
* cryotherapy
* electrosurgery
132
What topical treatment is used for viral warts?
How long does it take to work?
**salicylic acid**
this removes dead surface cells
it takes around 12 weeks to work effectively
133
What is cryotherapy and how long does this take to work?
this involves freezing the wart
it is a success after 3-4 months
134
What is involved in electrosurgery for treatment of viral warts?
How long does it take to heal and how often do warts recur?
* curettage & cautery used for large / persistent warts
* local anaesthetic is applied, the growth is cut away and the base is burned (permanent scar)
* it heals in 2 weeks but 20% warts recur
135
What is shown in these images?
**molluscum contagiosum**
this is a common childhood skin infection
136
What are the risk factors for molluscum contagiosium?
* children aged under 10
* warmer climates
* wet conditions (e.g. swimming pools)
* overcrowded environments
* atopic eczema (due to deficient skin barrier)
* immunocompromised individuals
137
What causes molluscum contagiosum?
How is it spread?
it is caused by the **Poxvirus**
it can be spread by:
* skin-to-skin contact
* indirect contact (e.g. through towel sharing)
* auto-inoculation following shaving / scratching
* sexual transmission
138
What are the general clinical features of molluscum contagiosum?
* clusters of **small, round papules** that are **1-6mm** diameter
* there can be a **few to hundreds** of papules
* papules are **white, pink or brown** and are shiny with umbilicated pit
* papules contain white, cheesy material
* papules arise in **warm/moist places** e.g. flexures
* frequently induce dermatitis
139
When are molluscum contagiosum papules infectious?
they are infectious when they are active
140
What methods can be put in place to reduce the spread during active episodes of molluscum contagiosum?
* washing hands
* avoid scratching lesions / shaving
* cover visible lesions with clothes / plasters
* avoid sharing towels / personal items
* adults should practice safe sex / abstinence
141
What are the physical treatments for molluscum contagiosum?
* picking out the white core
* cryotherapy
* laser ablation
142
What are the medical treatments for molluscum contagiosum?
* antiseptics - e.g. **hydrogen peroxide**
* wart paint - e.g. **salicylic acid**
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What are the complications associated with molluscum contagiosum?
* secondary bacterial infection (impetigo)
* secondary eczema
* conjunctivitis if the eyelid becomes infected
* large & numerous mollusca in immunocompromised individuals
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What is tinea?
Which areas of the skin are more at risk of infection?
this is a dermatophyte infection caused by **Ringworm fungus**
areas of the skin that are warm and moist are more at risk of infection
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What are the general clinical features of tinea infection?
* generally **unilateral and itchy**
* affects **superficial layers** of the skin
* **usually mild**, but can be severe in immunocompromised individuals
* presentation varies with site of infection
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Which part of the body is affected in tinea corporis?
What does it look like?
affects the **trunk and limbs**
involves itchy, circular/annular lesions
these are clearly defined with a raised, scaly edge
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Where is tinea cruris found?
What does it look like?
found in the **groin** and **natal cleft**
very itchy lesions that present similarly to tinea corporis
(itchy, circular/annular lesions that are clearly defined, raised with a scaly edge)
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Where is tinea pedis found?
What does this look like?
This is also known as **athlete's foot**
it presents as wet scales and fissures in the toe-webs, sole and dorsal foot
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Where is tinea mannum found?
What does it look like?
tinea mannum affects the **hand**
it presents as dry scaling in the palmar creases
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Where is tinea capitis found?
How does it present?
this affects the **scalp**
this presents as inflammation, broken hair and scales
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Where is tinea unguium found?
What does it look like?
this affects the **nails**
it presents with yellow discolouration
the nails will thicken and crumble
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What is tinea incognito?
What does it look like?
tinea incognito arises from **treating tinea with corticosteroids**
this presents with ill-defined lesions that are less scaly
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How are tinea infections diagnosed?
through skin scrapings or hair / nail clippings
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What are the first line treatments for tinea infections?
**1 - treat known triggers:**
* e.g. immunosuppressive condition, warm/wet environments
**2 - topical antifungals:**
* e.g. terbinafine
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What may be used if topical antifungals are not effective in treating tinea infections?
oral antifungals may be used for severe, widespread or nail infections
e.g. **itraconazole**
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What treatment should be avoided in tinea infections and why?
avoid use of topical steroids as they can cause tinea incognito
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What is candidiasis and what are the 3 most common forms?
it is a yeast infection (most common - candida albicans)
* oral candidiasis
* candida intertrigo
* vulvovaginal candida
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What are the risk factors associated with candidiasis?
* more common in infants / elderly
* warm environments
* occlusion - e.g. plastic underwear / dentures
* high oestrogen contraceptive pill
* pregnancy
* diabetes mellitus
* iron deficiency
* immunocompromised individuals
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What is the mechanism behind how candidiasis is caused?
it is a normal inhabitant of the GI tract that doesn't usually cause any problems
if an individual's defences are compromised, this can cause infection of the mucosa and skin
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What are the general clinical features of candidiasis?
it presents with white plaques with erythema
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What are the common candidiasis infections?
* oral
* angular chelitis
* vulvovaginal candidiasis
* balanitis (penile)
* intertrigo (skin folds)
* napkin dermatitis (nappy rash)
* chronic paronychia (nail fold) and onychomycosis (nail plate)
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How is candidiasis diagnosed?
through skin scrapings or hair/nail clippings
HOWEVER, candida can live on a skin/mucosal surface without developing infection
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What are the treatments for candidiasis?
**1 - treat known triggers:**
* e.g. immunosuppressive condition, warm wet environment
* poor hygiene in affected areas
**2 - topical antifungals:**
* e.g. terbinafine
**3 - oral antifungals:**
* used for severe, widespread or nail infections
* e.g. itraconazole
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What is a potential complication of candidiasis?
**invasive candidiasis**
this involves the spread of candida through the bloodstream and infection of internal organs & tissue
it occurs in severely immunocompromised or unwell individuals
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What is pityriasis versicolor?
this is a yeast infection
it is not infectious but may affect more than one family member
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What causes pityriasis versicolor?
What are associated risk factors?
it is caused by ***Malassezia Furfur***
* it occurs more commonly in young adults and males
* it is more common in humid, warm environments
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What are the general clinical features of pityriasis versicolor?
What does it look like?
* usually asymptomatic
* hyper-pigmented, scaly, brown patches (look like bran)
* or can be hypo-pigmented
* affects the upper trunk (chest & back)
* patches do not tan on sun exposure
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How is pityriasis versicolor diagnosed?
* microscopy
* fungal culture
* skin biopsy
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What are the treatments for pityriasis versicolor?
**1 - treat known triggers:**
* e.g. immunosuppressive condition, warm wet environment
**2 - topical antifungals:**
* e.g. terbinafine
**3 - oral antifungals:**
* used for severe or widespread infection
* e.g. itraconazole
