Derm Infections Flashcards
What is folliculitis?
What is the most common organism?
Inflamed hair follicle which can affect any hair bearing area - presents with a tender red spot with pustule
Usually bacterial - Staph Aureus
List 2 factors which worsen folliculitis
How do we manage it?
Things that cause regrowing hairs: shaving, waxing, electrolysis
Management: stop exacerbating factors, hygiene, swabs may be useful to treat infection
What is cellulitis and how does it present?
Infection of the lower dermis and subcutaneous tissue
Presents as red, painful, swollen skin with fairly well-defined margins and systemic symptoms
If a patient presents with cellulitis what should we ask them to do in terms of monitoring?
What is the clinical relevance of this?
Always ask patient to draw a line around the area to monitor the cellulitis and see if it spreads over time
If it does, patient may need to switch from oral antibiotic to IV antibiotics
List 4 risk factors for Cellulitis
- Trauma
- Previous episodes; re-infection in same area
- Venous disease; blood pooling in the area
- Chronic diseases - DM, immunosuppression
In what population is cellulitis most common?
Elderly
Most common causitive organism in cellulitis
- Strep pyogenes (2/3)
- S. aureus (1/3)
How is Cellulitis diagnosed and treated?
Diagnosis:
- Clinical
- Bloods: Incl WCC and CRP (normally ↑)
- Blood cultures (only if IV antibiotics are required)
Treatment:
- Uncomplicated - Oral Flucloxacillin/ Co-fluampicil, Analgesia and treatment of co-morbidites
- Systemic upset: Hospital admission, IVI/ IV Abx, O2
What is Erysipelas?
Similar to cellulitis BUT more superficial; affects upper dermis
Where and How does Erysipelas present?
Usually presents on lower legs but can affect face
Presents as:
- Sharp raised border
- Bright red, firm and swollen (cellulitis is firmer)
- Blistering may be present
- Painful and warm
In what population is Erysipelas most common?
Infants and elderly
What is the most common causitive organism in Erysipelas
Strep pyogenes and S. aureus
How is Erysipelas disagnosed and treated?
Diagnosed: Bloods (Incl WCC and CRP) and cultures
Management:
- RICE; Rest, Ice, Elevation and Compression
- Abx (Flucloxacillin first line)
Compare 2 differences between Cellulitis and Erysipelas
Syphilis is a STI causes by which organism?
What are the 4 stages of disease?
Treponema pallidum
Stages: primary, secondary, latent, tertiary
Presentation during each stage of syphilis
Painless ulceration at infection site - genitals/ anus/ oral mucosa of mouth (1o) followed by a widespread macular rash with secondary symptoms (2o)
Investigations for Syphilis
- blood test-MHA-TP
- Serology
- Dark ground microscopy
- PCR of swab samples
Management of Syphilis
Penicillin injection
What are the 2 types of Herpes and how does each present?
HSV-1: Oral Herpes
HSV-2: Genital Herpes
Present with characteristic fluid filled vesicles that burst to produce ulcers
How do we diagnose and treat Herpes
Diagnosis: NAAT or PCR testing of swab from ulcer or vesicle fluid
Management:
- ORAL Acyclovir 200mg 5x a day for 5 days
- Analgesia
- Salt bathing
What is Eczema Herpeticum and how does it present?
Rare and serious skin infection caused by one of the herpes viruses (NOT an STI)
Presents with clusters of itchy and painbul blisters
How do we diagnose and treat Eczema herpeticum?
Diagnosis: Swab for PCR but not realy helpful… need to treat ASAP anyway
Treatment:
- Conservative; no treatment if mild
- Topical antivirals; ZOVIRAX
- Oral antivirals +/- Abx for 2o bacterial infection ie. S. aureus infection
- ACICLOVIR; 200 mg 5 times daily for 5 days
What is Chicken Pox?
How does it present?
Highly contagious viral infection caused by the Varicella- zoster virus which mainly affects children
Presents with:
- ACUTE fever
- blistered, itchy, erythematous rash
- progresses to vesicles on the stomach, back and face, which then spreads to other parts of the body
List 4 associated symptoms of chickenpox
- Fever
- Headache
- Nausea, vomiting
- Chickenpox pneumonitis (in severe cases, potentially fatal; check for respiratory symptoms; RED FLAGS)
Chickenpox most commonly affects children, what is meant by the prodrome phase when it affects adults?
Prodromal phase upto 48 hours before the rash
Symptoms incl: fever, malaise, headache, loss of appetite and abdominal pain
Chickenpox is usually more severe in adults and can be life-threatening in complicated cases
What is Molluscum Contagiosum?
Skin infection caused by a poxvirus molluscum contagiosum that occurs in childhood. Causes localised clusters of epidermal papules called mollusca
Also seen in immunosuppressed adults
List 2 ways in which Molluscum Contagiosum spreads
- Direct and indirect contact
- Koebnerises; i.e. SPREADS WITH TRAUMA
What is the Koebner Phenomenon?
Appearance of new skin lesions of a pre-existing dermatosis on areas of cutaneous injury in otherwise healthy skin
Seen in MC
Describe the appearance of the skin lesions seen in Molluscum Contagiosum
- Clusters of small round UMBILICATED papules with an axy shiny look
- Do not coaslesce together but can group up together
- Umbilication= cratering in the middle
- Favours creases; moist warm areas
Treatment of Molluscum Contagiosum
Clears within 2 years; self-limiting for 1-2 years therefore no treatment available on NHS
Can cause ↑parental anxiety, so can also use:
- Salicylic acid
- Molludab; OTC prep, KOH 5%; helps clear within 2-3 days
Reccomended to leave alone as the risk of scarring ↑ with treatment but give Abx if needed for a 2o bacterial infection
What are Shingles and how does it present?
Localised, blistering and painful rash caused by reactivation of varicella-zoster virus (VZV)
ie from chicken pox-> can later erupt as shingles
Describe the characteristic distribution of shingles
Dermatomal distribution
Describe the course of shingles
- Eruption is preceded by pain on that patch of skin or feeling unwell-
- Blistering rash then starts
- Prodrome; unwell, painful skin with no rash
Lasts 7-10 days
What is the most common complication of shingles?
Incl 2 signs/symptoms of this
Postherpetic neuralgia - allodynia and hyperalgesia
What is another complication of shingles which is a potential medical emergency?
What investigations must we do for this?
OPHTHALMIC SHINGLES: risk of viral corneal infection which can affect sight
Do fluorescein staining in eyes to check for dendritic ulcers for viral infection
Check ear canal for blisters
Management of acute Herpes Zoster
- Antiviral treatment - ↓ pain and duration of symptoms if started within 1-3 days of onset
- Rest and analgesia
- Protective ointment for rash ie. petroleum jelly.
- Oral Abx for 2o infection
Management of Postherpetic neuralgia
PHN may be difficult to treat successfully, may respond to any of the following
- Early use of antiviral medication
- Local anaesthetic applications ie. Emler anaesthetic cream
- Topical capsaicin
- TCA’s eg. Amitriptyline
- Anti-epileptics ie. gabapentin and pregabalin
- Transcutaneous electrical nerve stimulation (TENS) or acupuncture
- Botulinum toxin ( Botox) into the affected area
What is Pityriasis Versicolor and how does it present?
A common fungal infection that causes small patches of skin to become scaly and discoloured
Can present with different colours; brown/ paler/pink patches but is ALWAYS symetrical!
What Fungi causes pityriasis versicolor?
What other condition is also cause by this organism?
Malassezia infection
Also causes seborrheic dermatitis
Diagnosis and treatment of Pityriasis versicolor?
Diagnosis: Clinical features alone (yellow-green wood lamp tinge, scrapings)
Treatment:
- Topical antifungals - Ketoconazole/Terbinafine
- Oral antifungals; if disease does not resolve eg. oral Fluconazole/ Ketoconazole
Impt DDx for Pityriasis Versicolor
Vitiligo
How does oral candidiasis present?
How would you treat?
Presents with painful white plaques on tongue, inner cheeks, gums, tonsils or throat. Lesions can be painful and may bleed slightly when scraped
Treatment: Oral Nystatin and Miconazole
How does vulvovaginal candidiasis present?
- Profuse, white, curd-like discharge
- Vaginal itch, discomfort and erythema
- Inflammation can lead to dysuria and dyspareunia
How would you diagnose and treat vulvovaginal candidiasis
Diagnose: high vaginal swab for microscopy and culture
Treatment:
- Oral fluconazole (anti-fungal) OR
- Intravaginal antifungal cream or pessary - econazole
List 4 other candidal infections
- Balanitis - Swollen head of penis, pink/red rash, swelling, sore, discharge
- Intertrigo - inflammation in folds of the skin eg. breasts, elbow creases etc..
- Napkin dermatitis
- Nail infections
What are Dermatophytosis (tinea) infections?
How do we classify the different types?
Fungal infections caused by dermatophytes - group of fungi that invade and grow in dead keratin
Named depending on which part of the body is affected eg. Tinea pedis - foot (Athlete’s foot)
Management of Dermatophyte Infections
- Treat underlying cause; DM, Immunosuppression, Eczema, Venous disease
- TOPICALS: all below +/- Hydrocortisone
- Clotrimazole
- Terbinafine
- Miconazole
- Amorolfine nail lacquer
- ORAL ANTIFUNGALS: Itraconazole
- For treatment resistant disease
- If disease is widespread/ extensive
- Affecting hair bearing areas
What are scabies and how does it present?
Very itchy rash caused by a parasitic mite (Sarcoptes scabiei) that burrows in the skin surface esp in wed spaces of fingers; visible after some time
List 3 risk factors for scabies
- Poverty/ Overcrowding
- Institutions ; care homes. Orphanages
- Poor hygiene
Spread by direct contact
What sign can be seen under dermoscopy indicating Scabies
Chevron Sign; wing-shaped/ paraglider sign
Medical treatment of scabies?
- Topical Permethrin 5% (LOTION), leave on for 8-10 hrs - Repeat after 8 days
- Oral Ivermectin; if patient is unable to apply cream, poor absorption, in care homes
What MUST we do if an individual is diagnosed with scabies?
CONTACT TRACING
In additon to medical treatments, list 2 other things we should advise patients
- Bed linen, towels and clothing should be laundered after treatment
- Non-washable items should be sealed in a plastic bag and stored for one week
- Rooms should be thoroughly cleaned with normal household products; fumigation or specialised cleaning is not required.
- Carpeted floors and upholstered furniture should be vacuumed.
What is meant by Pediculosis capitis vs Pediculosis corporis?
HEAD LICE; Pediculosis capitis
BODY LICE; Pediculosis corporis
Treatment of lice?
- Combing
- Suffocating agent; 4% Dimeticone (hedrin)
- Insecticide- Permethrin
