Year 4 Infectious diseases/ Dermatology Flashcards
What is this?
Tinea capitis
Tinea capitis summary
Pathogen
- Trichophyton rubrum (dermatophyte)
- Microsporum canis (from pets)
Investigation
- Skin scraping and microscopy
Manageemnt
- Topical terbinafine
what is this?
Eczema herpeticum
eczema herpeticum background
Pathogens
- HSV-1
- HSV-2
- Cocksackievirus
Risk factors
- Patients with eczema are prone
- Immunosuppressed
Management
- Acyclovir
- Treat bacterial superinfection
what is this?
herpetic keratitis
herpetic keratitis
Presentation
* Painful red eye
* Photophobia
* Vesicles around the eye
* Foreign body sensation
* Watering eye
* Reduced visual acuity. This can vary from subtle to significant.
Investigations
- Fluorescein -> shows dendritic corneal ulcer
- Corneal swabs or scrapings to isolate the viral using a viral culture or PCR
- Slit lamp examination
Management
- Same day appointment with ophthalmologists
- Aciclovir topical or oral
- Ganciclovir eye gel
- Topical steroids may be used alongside antivirals to treat stromal keratitis
- Corneal transplant to treat corneal scarring caused by stromal keratitis
Prognosis
bacterial keratitis
Presentation
- Rapid onset ocular pain
- Redness
- Hypopyon
- Photophobia
- Discharge
- Decrease vision
Investigations
- Vision
- Fluoresceine
- Intraocular pressure
- Pupil assessment
- Slit lamp examination
- Corneal scrapings -> microscopy and sensitivity
Management
- Contact lenses should be discontinued
- Topical antibiotic drops
- Broad spec oral antibiotics if deep ulcers or scleral involvement
- Pain relief
what is this?
Erysipelas
erysipelas
Pathogens
- Staphyloccus aureus
- Streptococcus pyogenes
Presentation
- Pigmented
- Raised rash
- Borders very well demarcated vs cellulitis
Management
- Flucloxacillin
- Vancomycin (pen allergic)
what is this?
Chicken pox lesions
Chicken pox
Pathogen: Varicella zoster
Presentation
- Lots of diff stages of chicken pox -> vesicles -> scabs
- Starts on the trunk and face and spreads outwards towards limbs
- Coryzal symptoms
High risk
- Pregnant -> watch out for pneumonitis
- Immunocompromised
- Very young -> watch out for pneumonitis
- Adults -> watch out for pneumonitis
Complications
- Can cause encephalitis
- Superinfection
- Post herpetic neuralgia (chronic pain)
- Ophthalmic shingles
- Ramsay hunt -> facial nerve palsy
Management
- Supportive in those without risk
- Acyclovir
- VZIG for patients who cannot have acyclovir e.g. pregnant
what is this?
Shingles
shingles
Primary infection with VZV manifests as chickenpox (varicella). Following resolution, viruses establish latent infection within sensory nerve ganglions. Reactivation of such dormant viruses results in shingles (herpes zoster).
management: oral aciclovir
what is this?
tinea cruris
tinea cruris
can be caused by self inoculation e.g. other parts of body infected
- use clean towels
- dont share towels
what is this?
Chancre
Chancre
- Treponema pallidum (syphilis)
- Painless lesion
- Primary infection
What is this?
Secondary syphilis
- Widespread macula rash on soles of foot
tertirary syphilis presentation
- Neurosyphilis
- Gummas
- CVS complications e.g. AA
Neurosyphilis
- Headache
- Altered behaviour
- Dementia
- Tabes dorsalis (demyelination affection spinal cord posterior columns)
- Ocular syphilis
- Paralysis
- Sensory impairment
ocular syphilis
posterior uveitis and panuveitis are the most common. Additional manifestations may include anterior uveitis, optic neuropathy, retinal vasculitis and interstitial keratitis
- may cause RAPD if optic neuropathy
Gummas
(granulomatous lesions that can affect skin)
what is this?
impetigo
impetigo
pathogen
- Group A strep (strep pyogenes)
- Staph aureus
Management
- Benzyl peroxide
- Fusidic acid
- Oral flucloxacillin
what is this?
candidal intertrigo
candidal intertrigo
- Red, itchy and satellite lesions
- Topical clotrimazole or oral fluconazole
- RF
o DM
o Immunosuppressed
what is this?
Norwegian crusted scabies
what is this?
Norwegian crusted scabies
norwegian crusted scabies
- Severe form of scabies, means thousand or millions of scabies mites are present
- Normal scabies can develop into crusted scabies after a skin reaction. The condition affects all parts of the body, including your head, neck, nails and scalp. However, unlike normal scabies, the rash associated with crusted scabies usually doesn’t itch.
Risk factors
- older
- dementia
- immunocompromised
- institutional accomodation
Topical
- First line: permethrin cream
- Second line: malathion lotion
what is this?
Molluscum contagiosum
molluscum contagiosum
Pathogen
- Molluscum contagiosum virus, which is a type of poxvirus
Management
- No treatment or change in lifestyle is required and children can continue all their normal activities. They should avoid sharing towels or other close contact with the lesions to minimise the risk of spreading the infection. Usually just simple reassurance and education is enough.
- Treat bacterial superfinfection (often caused by scratching) - topical fuscidic acid or oral flucloxacillin.
what type of meningitis
Viral meningitis
- normal glucose
- clear
- high lymphocytes
Management
Supportive treatment (aciclovir is not routinely used like in viral encephalitis)
what type of meninigitis is this
Tuberculosis
- low glucose
- turbid
- lymphocytes
Investigations: acid-fast stain
Management
* R – Rifampicin for 6 months
* I – Isoniazid for 6 months
* P – Pyrazinamide for 2 months
* E – Ethambutol for 2 months
what type of meningitis is this?
Bacterial meningitis
- Low glucose
- High protein
- High polymorphs (neutrophils)
- Doesn’t have to be cloudy, can be clear even if bacteria)
due to age group think: meningococcal (neisseria meninigitis)
Management
- community : stat dose of benzylpenicillin
- Hospital: ceftriaxone + vancomycin
- Dexamethasone for hearing
what could this suggest?
Could be viral encephalitis
- Treat with aciclovir
where do basal cell carcinomas originate
stratum basale
- grow slowly
- very rarely metastasise
- most common type of skin cancer
where do squamous cell carcinomas originate
stratum spinosum
- grows quickly
- can metastasise to local lymph nodes
- more common in immunocompromised patients (ask patient)
where do melanomas originate
melanocytes
- metastise quikly to lymph nodes and blood vessels
- requires urgent treatment
- ABCD method of detection
how to differentiate between BCC and SCC
BCC
- Skin coloured (however can be pigmented)
- Pearly (especially on borders if ulcerated)
- Telangiectasia
- Chrystalline structures, i.e. white shiny lines
SCC
- ulcerated
- hallmark of SCC is keritinisation
- crusty/scaly
- blood spots are common
both can be itchy and bleed
what are these ?
BCC
what are these ?
SCC
difference between different skin cancers in photos
ABCDE of melnoma
> 6mm
A 53-year-old man presents with a nodule on his chin. He is concerned because it has grown extremely rapidly over the course of the preceding week. On examination he has a swollen, red, dome shaped lesion with a central defect that contains a keratinous type material.
Keratoacanthoma
-> now not particularly distinguihsed from SCC- must be biopsied to tell the difference
Very rapid growth phase. The keratin core is the clue as to the true nature of the lesion.
Actinic keratosis and SCC
Actinic keratosis is viewed as a premalignant lesion because there are atypical keratinocytes present in the epidermis. In a person with 7 actinic keratosis, the risks of subsequent SCC is of the order of 10% at 10 years. The primary lesion is a rough erythematous papule with a white to yellow scale. Lesions are typically clustered at sites of chronic sun exposure.
Squamous cell carcinoma in situ
Also known as Bowen’s disease the commonest presentation of in situ SCC is with an erythematous scaling patch or elevated plaque arising on sun-exposed skin in an elderly patient. Lesions may arise de novo or from pre-existing actinic keratosis.
Pathologically there is full thickness atypia of dermal keratinocytes over a broad zone. Nuclear pleomorphism, apoptosis and abnormal mitoses are all seen.
Invasive SCC
The commonest clinical presentation of SCC is with an erythematous keratotic papule or nodule on a background of sun exposure. Ulceration may occur and both exophytic and endophytic areas may be seen. Regional lymphadenopathy may be present.
Pathologically there is a downward proliferation of malignant cells and invasion of the basement membrane. Poorly differentiated lesions may show perineural invasion and require immunohistochemistry with S100 to distinguish them from melanomas (which stain strongly positive with this marker).
summary of different BCC
Pyogenic granuloma
These present as friable overgrowths of granulation at sites of minor trauma. They may be ulcerated and bleeding on contact is common. They may be treated with curettage and cautery, formal excision may be used if there is diagnostic doubt.
seborrheic keratosis
Seborrhoeic keratosis is a harmless warty spot that appears during adult life as a common sign of skin ageing. Some people have hundreds of them.
how to describe a lesion in derm
Non-pigmented: SCAM
Pigmented: ABCDE
SCAM
Size and shape
Colour
Associated symptoms
Morphology and margin
size and shape of lesion
Primary skin lesions are those which develop as a direct result of a disease process.
Macule: a flat area of altered colour less than 1.5cm in diameter.
Patch: a flat area of altered colour greater than 1.5cm in diameter.
Papule: a solid raised palpable lesion less than 0.5cm in diameter.
Nodule: a solid raised palpable lesion greater than 0.5cm in diameter.
Plaque: a palpable flat lesion usually greater than 1cm in diameter. Most plaques are raised, however, some may be thickened without being visibly raised.
Vesicle: a raised, clear fluid-filled lesion less than 0.5cm in diameter.
Bulla: a raised, clear fluid-filled lesion greater than 0.5cm in diameter.
Pustule: a pus-containing lesion less than 0.5cm in diameter.
Abscess: a localised accumulation of pus.
Wheal: an oedematous papule or plaque caused by dermal oedema.
Boil/furuncle: staphylococcal infection around or within a hair follicle.
Carbuncle: staphylococcal infection of adjacent hair follicles (i.e. multiple boils/furuncles).
shape of lesion
– Annular – open circles.
– Discoid (or nummular) – filled circle.
– Arculate – incomplete circles.
– Recticulate – fine lace-like pattern.
– Stellate – star shaped.
– Digitate – finger shaped.
– Linear – straight line.
– Serpiginos – snake-like.
– Whorled – swirling pattern.
associated symptoms
itching
bleeding
crusting
ulceration
excoriation
scar
describing distribution of rash
colour of rash
maculopapular rash
A macule is a flat, reddened area of skin present in a rash. A papule is a raised area of skin in a rash. Doctors use the term maculopapular to describe a rash with both flat and raised parts.
morbilliform rash
a type of maculopapular rash asscoiated with drug reaction
- symmetrical
- involvement of the trun and some portion of the extremitites
- blanching
- macules and papules become congluent with time
chicken pox rash
macular -> papular -> vesciular lesion -> scabs
