Dermatology Flashcards
Describe the different types of skin carcinoma
- basal cell carcinoma: usually presents as raised, smooth, pearly bump on the sun-exposed skin of head neck or shoulders, ulceration and telangiectasia may also feature
- squamous cell carcinoma: common presents as a red scaling thickened patch over sun-exposed skin. More malignant than BCC but less common, also associated with immunosuppression and HPV.
- malignant melanoma: the least common but most malignant usually presents as an asymmetrical area with irregular border and colour variation from shades of brown to black. Though some more aggressive melanomas called amelanotic appear pink, red of fleshy. Tend to be larger than 6mm and evolve over time. ABCDE Criteria, Asymmetry , Border irregular, Colour variation, Diameter greater than 0.5cm, Evolving over time. Subungual melanoma presents I totally with pigment band of nail that becomes wider, can cause lifting of the nail (onycholysis), Hutchinsons sign is an important clue characterised by extension of brown or black pigment from the nail bed to the cuticle and nail folds.
What is a macule?
Flat non-palpable lesion less than 0.5cm in size
What is a patch?
Flat non-palpable lesion greater than 0.5cm, I.e. A large macule
What is a nodule?
A large raised lesion greater than 0.5cm in diameter I.e a solid lump
What is a papule?
A small well defined raised lesion less than 0.5cm in diameter
What is a plaque?
A raised flat-topped lesion usually over 2cm in diameter.
What is a vesicle?
Small fluid-filled blisters less than 0.5cm in size
What is a bulla?
A large fluid-filled blister greater than 0.5cm in diameter I.e. A large vesicle
What is a pustule?
A pus-filled blister. Usually the size of vesicles
What is scale?
Fragment of dry skin, flakes of keratin
What is crust?
Dry brownish exudate
What is ulceration?
Loss of the epidermis
What is an erosion?
Superficial break in epidermal surface, heals without scarring
What is excoriation?
A scratch hitch has broken the surface of the skin. It is a superficial erosion secondary to scratching.
What is lichenification?
Skin thickening with hyper pigmentation, giving a shiny appearance, it is a result of repeated trauma
What is koebnerisation?
Skin lesions which develop at the site of injury e.g. A scar. Seen in psoriasis, lichen planus, plane warts, and vitiligo
What are the main types of eczema (dermatitis)?
- atopic eczema
- allergic contact dermatitis
- irritant dermatitis
- adult seborrhoeic dermatitis
- discoid eczema
Describe atopic eczema, it’s presentation, and management
Acute eczema causes a rash.
Presentation: Typically in children presents as itchy red skin. Family history of atopy is common. May suffer from asthma or hay fever. Itching may lead to staph infection.
Management: -rule out other types of dermatitis - education - topical: emollients/bath emollients at least twice a day [use greasy eg 50/50 emulsifying ointment in severe; other types epiderm, diprobase] Steroids - on active sites. [ face, flexures, groins (<5 days) - 1% hydrocortisone, or clobetasone 0.05%; elsewhere (<1week) - betamethasone 0.1%, or clobetasone] - systemic (severe non-responsive): ciclosporin, tacrolimus - others: Wet wraps, phototherapy
Describe Irritant dermatitis, it’s presentation, and management
Presentation: think of new soaps, new gloves etc.
Presentation: typically dry erythematous skin on hands. Common irritants that may come up in history include, soap, oils, solvents, alkalis, too much water. Occupation is important.
Management:
- avoid irritants
- hand care I.e. Regular emollients, careful drying of hands
- topical steroids for acute flare-ups
Describe allergic contact dermatitis, it’s presentation, common causes, and management
It is a type IV hypersensitivity reaction.
Presentation: the pattern of contact gives a clue at a cause tends to be well demarcated and of a certain shape e.g. Ring, or around neck line of shirt
Common allergens: nickel (jewelry, watches, coins, keys), chromates (cements, leather), plants, topical neomycin, framycetin, antihistamines.
Management:
- consider patch testing to list allergens to avoid
- topical steroid depending on severity
Describe adult seborrhoeic dermatitis, it’s presentation, and management.
Presentation: Common, red scaly rash affecting scalp (dandruff), eyebrows, nasal labial folds, cheeks and flexures
Management:
- mild topical steroid/antifungals preparations e.g. Daktacort
- treat intermittently as needed.
What is a halo nevus?
Benign mole occurs most often on the back of young adults. Appears as a fading mole with a surrounding white hypopigmented area. The white halo results from loss of melanocytes by lymphocyte action. May repigment
Describe Toxic epidermal necrosis, it’s signs, causes and management.
The bad end of the erythema multiforme/ Stevens-Johnson syndrome spectrum. Mortality approx 30%
Signs: Widespread erythema, then necrosis of large sheets of epidermis. Mucosae severely affected. Risk of TEN in HIV patients in 1000-fold higher.
Causes: Sulfonamides, Anticonvulsants, penicillins, allopurinol, NSAIDs.
Management:
- Stop likely drug offenders
- specialist managemeant in a dermatology or burns unit
- short-term dexamethasone pulse therapy IV Ig may be needed
What are the different classifications for skin types?
Type I - Pale white, blond or red hair, blue eyes, freckles, always burns, never tans
Type II - White, fair, blond or red hair, blue green or hazel eyes, usually burns, tans minimally
Type III - Cream white, fair with any hair or eye colour, quite common, sometimes mild burn, tans uniformly
Type IV - moderate brown, typical Mediterranean skin tone, burns, always tans well.
Type V - Dark brown, middle eastern skin types, very rarely burns, tans very easily
Type V - deeply pigmented dark brown, never burns, never tans.
