Dermatology Formative Flashcards
Gel
Thickened aqueous solution
-semi-solid, containing high
Lotion
Liquid formulation
Suspension of medication in water/alcohol/other liquid
Pastes
Semi-solids, stiff, greasy, difficult to apply, often used in cooling, drying, soothing bandages
-contain finely powdered material
Ointment
Semi-sold grease/oil, no preservative, less cosmetically attractive, greasy
Cream
Semisolid emulsion of oil in water, contains preservative, cosmetically acceptable, non greasy
Examination for herpes simplex
Blister fluid: electron microscopy, viral culture and PCR
Usual cause of cellulitis?
beta haemolytic streptococcus
Diagnosis of cellulitis?
Serologically (so do a blood test and look for antibodies)
Treatment for cellulitis?
Phenoxymethylpenicillin (or erythromycin) and flucloxacillin
Investigation for scabies?
Skin scrapings for microscopy
Investigation for ring worm?
Skin scraping for microscopy and culture, and woods light
Investigation for impetigo?
Swab of lesion sent in bacterial container for microscopy and culture
Atrophy
Thinning of the skin
Crusted
Dried serum or exudate on the skin
Scaly
Visible flaking and shredding of surface skin
Erosion
Partial epidermal loss
denuded area of skin
Weal
Itchy raised “nettle rash” like swelling due to dermal oedema
Large, flat-topped elevated, palpable lesion
Plaque
Organism causing boils?
Usually staph aureus
Treatment for boils?
Erythromycin (occasionally incision and drainage)
Organsim causing pitted keratolysis?
Corynebacterium
-frequently involves the soles of the forefoot and appears as numerous punched out circular lesions
Chronic lesions of lupus vulgaris are at high risk of developing what?
High risk of developing squamous cell carcinoma
How are warts spread?
Warts are spread by direct contact, they are also associated with trauma
Common cutaneous infection of childhood caused by pox virus. Lesions are multiple small (1-3mm) translucent papules which often look like fluid filled vesicles but are infact solid. Individual lesions may have a central depression called a punctum. They exhibit the Kobner phenomenon. They occur at any body site including the genitalia
Molluscum contagiosum
-rarely require treatment as they spontaneously resolve
Disease of sheep and goats
- caused by pox virus
- 1-2 cm reddish papules with a surrounding erythema which usually becomes pustular
Orf
- lesions resolve spontaneously after 4-6 weeks
- Occasionally, orf is complicated by erythema multiforme
What can complicate orf?
Erythema multiforme can complicate orf
Asymmetrical scaly patches which show central clearing and an advancing scaly, raised edge
Tinea corporis
- central clearing is not a universal feature and it is recommended that all asymmetrical scaly lesions should be scraped for fungus
- Ring worm of the face often arises after the use of topical steroids
When does ringworm of the face often arise?
Ringworm of the face often arises after the use of topical steroids
The skin in the toe clefts looks white, macerated and fissured
Tinea pedis (athletes foot)
How is scalp ringworm spread?
Scalp ringworm is spread by close contact and may also be spread indirectly by hairdressers
Clotrimazole, miconazole, terbinafine
Anti-fungals (e.g. for ringworm)
Intensely itchy rash caused by the mite sarcoptes scabiei
It presents clinically with itchy red papules (or occasionally vesicles and pustules) which can occur anywhere in the skin but rarely on the face
-especially web spaces between fingers and toes
-palms and soles
-around wrists and axillae
-male genitalia
-around nipples and umbilicus
Scabies
Treatment for scabies
Permethrin 5% (tobical sabicide)
-applied and washed off after ten hours
Enhance rehydration of epidermis
-For all dry/scaly conditions esp. eczema
Emollients
How much emollient do you need to prescribe weekly?
Prescribe 250-500g weekly
Vasoconstrictive
Anti-inflammatory
Anti-proliferative
Topical cortico-steroids
Hydrocortisone 1%
Mild
Clobetasone Butyrate 0.5%
Moderate
Modrasone
Moderate
Elocon
Potent
Betamethasone valerate 0.1%
Potent
Clobetasol proprionate 0.05%
Very potent
Use of topical steroids
Eczema (dermatitis)
Psoriasis
Other non-infective inflammatory dermatoses e.g. lichen planus
Keloid scars (usually intralesional)
Quantity of topical steroid needed for whole body application?
20-30g
Quantity of steroid in 1 fingertip unit?
And how much does this cover?
1/2g
Covers 2 hand areas
Topical steroid side effects?
Thinning of skin, purpura, stretch marks
Perioral dermatitis
Fixed telangectasia
Steroid rosacea
May worsen or mask infections
Systemic absorption
Tachyphylaxis : decrease in response to anti-inflammatory effects
Rebound flare of disease (esp. psoriasis)
Topical steroid
Povidone iodine
Chlorhexidine
Triclosan
Hydrogen peroxide
Antiseptics
have bacteriostatic/ bactericidal effects
Anti-septic you could use in acute exudative eczema or pompholyx?
Potassium permanganate rinse/soak/bath
Topical antibiotics for acne?
Clindamycin, erythromycin, tetracycline
Topical antibiotics for rosacea?
Metronidazole
Topical antibiotics for impetigo?
Mupirocin, fusidic acid
Type of anti-viral required for eczema herpeticum?
Oral anti-viral needed for eczema herpeticum
Type of medication needed for candidi and pityrasis vesicolour?
Anti-yeast
Medication needed for dermatophytes (ringworm)
Anti-fungal
Menthol
Capsaicin
Camphor/phenol
Crotamiton
Anti-pruritics
-Menthol is added to calamine and other lotions/creams to impart cooling senstation
Capsaicin is from red chilli peppers –> depletes substance P at nerve endings and reduces neurotransmission, effect gradually builds
Camphor/phenol –> for pruritis ani
When might you use camphor/phenol?
For pruritis ani
This is from red chilli peppers, depletes substance P at nerve endings and reduces neurotransmission, effect gradually build
Capsaicin
Give an example of a keratolytic
Salicylic acid
10-40%
Used to soften keratin: Viral warts Hyperkeratotic eczema & psoriasis Corns and calluses To remove keratin plaques in scalp
Keratolytics
e.g. salicylic acid 10-40%
What is podophyllin used for?
Genital warts
Treatment of warts?
Keratolytics e.g.Salicylic acid Formaldehyde Glutaraldehyde Silver nitrate Cryotherapy (usually liquid nitrogen) Podophyllin (genital warts)
Topical psoriasis treatment?
Emollients and choice of: Coal tar Vitamin D analogue Keratolytic Topical steroid Dithranol
Pros and cons of vitamin D analogues?
Clean, no smell
Easy to apply
BUT can be irritant
Use limited to ?100g weekly
Side effects of dithranol
Difficult to use and irritant and stains normal skin
“dithranol staining and burning”
Treatments for scalp psoriasis
Greasy ointments to soften scale
Tar shampoo
Steroids in alcohol base
Vitamin D analogues
Psoriasis in axilla
Topical steroids for face, flexures and groin/genitals
Imidazoquinoline amine
Immune response modulator
Enhances innate & cell-mediated immunity
Anti-viral, anti-tumour effects
Imiquimod
Tacrolimus, pimecrolimus
Calcineurin inhibitors
- suppress lymphocyte activation
- topical treatment of atopic eczema, especially face, children
When would you use calcinuerin inhibitors?
Topical treatment of atopic eczema, especially face, children
- does not cause cutaneous atrophy
- may cause burning sensation on application(?risk of cutaneous infections ?? risk of skin cancer?)
Side effects of topical therapies?
Burning or irritation
Contact allergic dermatitis
Local toxicity
Systemic toxicity
UVA and UVB, which is responsible for direct/indirect DNA damage
UVA: indirect damage
UVB: direct damage
Being female and having malignant melanoma?
Improve the prognosis
Adverse prognostic factors for malignant melanoma
Vascular invasion
Nodular subtype
Ulceration
Where do you get arterial ulcers?
Foot/mid shin
Where do you get venous ulcers?
Medial or lateral malleolus
What is the breslow thickness?
Depth from the granular layer of the epidermis to the deepest melanoma cell
Cutaneous horn
Made of keratin
-most common lesions are seborrhoeic keratoses
Where do dermatofibromas commonly develop?
Lower legs
