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 with less scale and less demarcated than psoriasis.
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
- control not cure
- use emollients twice a day, greasy better in severe eczema e.g. 50/50 emulsifying ointment and liquid paraffin.
- daily steroid ointment for active sites, strengths vary on severity, site and age. For face, flexures and groin 1% hydrocortisone for other areas quick control can be achieved with betamethasone 0.1% ointment for less than 7days.
- if no response consider systemic treatment with ciclosporin.
- beware eczema herpitcum concurrent infection with herpes simplex.
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 features, associated conditions, and management.
Seborrhoeic dermatitis in adults is a chronic dermatitis thought to be caused by an inflammatory reaction related to proliferation of a normal skin inhabitant a fungus called Malassezia Furfur.
Features: Common, red scaly rash affecting scalp (dandruff), eyebrows, nasal labial folds, cheeks and flexure, otitis externally and blepharitis may also develop.
Associated Condition:
- HIV
- Parkinson’s disease
Management:
- Scalp management: over the counter preparations containing Zinc pyrithione (Head and Shoulders), and tar are first line. Ketoconazole is second line. Selenium sulphide and topical corticosteroids may also be useful.
- Face and body management: Topical antifungals e.g. ketoconazole. Topical steroids. Difficult to treat and recurrences are common.
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.
What is a capillary haemangioma (strawberry naevi)?
Occurs in neonates as a rapidly engaging red spot. Most go by the age of 5-7 years. No treatment is required unless a vital function is imparied e.g. Obscuring ears or eyes. If treatment is required Propanalol is the drug of choice
Describe Acanthosis Nigricans and its causes.
Pigmented, rough velvety thickening of axillary, neck or groin skin with warty lesions often associated with Diabetes Mellitus.
Causes:
- Gastrointestinal cancer
- Endometrial Cancer
- Diabetes Mellitus
- Obesity
- PCOS
- Acromegaly
- Cushing’s Disease
- Hypothyroidism
- Familial
- Prader-Willi Syndrome
- Drugs: OCP, Nicotinic acid
Describe Alopecia, it’s types and causes.
Hair loss may be scarring or non-scarring. Non-scarring causes may be reversible but scarring alopecia implies irreversible loss. Scalp disorders may be signs of skin elsewhere e.g. Lichen planus or SLE.
Scarring Causes:
- Nutritional (Fe or Zn deficiency),
- Androgenetic
- autoimmune (alopecia areata, smooth round patches of hair loss on scalp, hairs like exclamation marks are a typical feature, often spontaneously regrows)
- Telogen effluvium (shedding of Telogen phase hairs after period of stress eg. Childbirth, surgery, severe illness.
Scaring Causes:
- Lichen planus
- discoid lupus Erythematosus
- trauma
Describe Alopecia Areata, its symptoms and management.
An autoimmune cause of non-scarring hair loss.
Symptoms: Smooth round, well demarcated patches of hair loss on scalp with exclamation like hairs are a typical feature.
Management:
- Often spontaneously regrows by 1 year in 50% and in 80-90% eventually.
- May require topical steroids, phototherapy, contact immunotherapy.
What is a kerion?
A raised spongy honeycomb lesion on the scalp or beard which occurs as the result of a hosts response to a fungal ringworm infection of the hair follicles accompanied by secondary bacterial infection. It is a severely painful inflammatory response.
Describe Pruritis, it’s causes and investigations.
Can be very distressing, skin will usually be scraped or rubbed and number so secondary skin signs are seen such as excoriation a, lichenification, papules or nodules.
Causes: primary or systemic?
- Primary include Scabies (burrows in finger-webs, wrists, groin buttock), urticaria, atopic eczema (flexural eruption, lichenification), dermatitis herpetiformis (very itchy blisters on elbows and shoulders), lichen planus (flat violet wrist papules)
- Systemic such as IDA (koilonychia, pale), lymphoma (nodes, hepatosplenomegaly), hypo/hyperthyroidism, liver disease (jaundice, spider naevi), chronic renal failure (dry sallow skin), malignancy (clubbing, masses), drugs.
Investigations: FBC (anaemia, lymphoma), ESR (vasculitis), Ferritin (IDA), LFT, U+E, Glucose, TSH, CXR.
Describe Discoid Eczema, it’s presentation, and management.
Presentation: Coin-shaped lesions may begin as vesicles. Typical patient is a male 50-70yrs or female 20-30rs, with somewhat symmetrical round very itchy vesicles or popular plaques of on legs +/- trunk and arm, but not face. They may crust and get infected by staphs before flattening into hyperpigmented macules.
Management:
- Sunlight may help.
- lukewarm baths, moisturisers, steroid ointment, oral antihistamine.
Describe Psoriasis, the types, it’s presentation, and management.
Psoriasis is a chronic inflammatory skin condition, peaking in 20s and 50s. It is due to epidermal proliferation and T-cell driven inflammatory infiltration of the dermis and epidermis.
Types + Presentation:
- Plaque psoriasis, Symmetrical well-defined red plaques with silvery scale on extensor aspects of the elbows, knees, scalp, and sacrum.
- Guttate psoriasis, Small plaques (Guttate) are see in the young (especially if associated with concurrent streptococcal infection).
- Pustular psoriasis (palmoplantar)
- Flexural psoriasis, Flexures (axillae, groins, submammary areas, and umbilicus) also frequently affected but lesions are non-scaly
- Nail changes in 50% such as pitting, onchylosis (separation from nail bed), thickening and subungual hyper keratosis).
- Erythrodermic psoriasis is a variant which affects more than 80% of the body area, it may cause severe systemic upset, fever, raised WBC, dehydration. Also triggered by rapid withdrawal of steroids.
- Psoriatic arthritis, some develop a sero-negative arthropathy.
Management:
- education is vital, control not cure. Encourage support group. Remove triggers e.g. B-blockers antimalarials, lithium, NSAIDs, alcohol, obesity, smoking.
- If mild creams are mostly used e.g. Vitamin D analogues calcipotriol and betamethasone (dovobet)
- if arthropathy consider, methotrexate, infliximab, etanercept
- moderate severe disease may benefit from UV phototherapy + etanercept or adalimumab
What is exanthem?
Widespread rash that accompanies system illness typically viral infection may occur in a laterothoracic variant affecting one side of the body typically in younger children.
What is a Mongolian blue spot?
Benign blue grey patch/naevi that dissapers on its own.
What is the fingertip rule?
One pea sized portion of steroid cream can cover the area of 2 adult hands.
What are the different strengths of steroid cream from least potent to most?
- Hydrocortisone = mild
- Clobetatsone = moderate
- betamethasone = potent
- Clobetatsol = super potent
Describe Erythema Multiforme, it’s causes, and management
Minor form: target lesions, usually on extensor surface especially of peripheries, palms and soles.
Major form: Steven-Johnson syndrome/toxic epidermal necrolysis. Associated with systemic upset, fever, severe mucosal involvement, including conjuctivae.
Causes: herpes simplex (70%), mycoplasma, viruses (minor form), drugs especially Sulfonamides, penicillins (major form).
Management:
-treat/stop cause. Supportive care. Dermatological input.
Describe scabies, it’s signs, and management.
A highly contagious, common disorder particularly affecting children and young adults. Spread is direct person to person. The female mite digs a burrow (pathognomonic sign, a short wavy grey or red line on the skin surface) and lays eggs which hatch as larvae. The itch and subsequent rash is probably due to allergic sensitivity to the mite and its products.
Signs: It presents as very itchy papules, vesicles, pustules, nodules affecting finger-webs, wrist Flexures, axillae, abdomen (especially around umbilicus and waistband area), buttocks and groin.
Management:
- Permethrin 5% dermal cream applied o all areas of the skin from neck down for 24h. All members of household should be treated at the same time even if asymptomatic.
- Crotamiton cream is an anti-pruritic medication which may help.
Describe Acne Vulgaris and its management
Basal keratinocytes proliferation in pilosebasceous follicles (androgen and CRH driven), increased sebum production, propionibacterium acnes colonisation, inflammation and comedones (white and black head) blocking secretions hence papules, nodules, cysts and scars.
Management:
- mild acne, mainly facial comedones, topical benzoyl peroxide as twice weekly wash, roll on antibiotics (clindamycin as Dalacin T)
- moderate acne, inflammatory lesions face and torso, doxycycline for 4-6months with topical benzoyl peroxide twice weekly. Then topical retinoids e.g. Adapalene or isotretinioin used in combination with above.
- severe acne, nodules, cysts, scars, isotretinioin is first choice, it is teratogenic so good contraception must be used during and for 1 month after treatment. Monitor triglycerides (can cause hyperlipidaemia), AST, ALT (can cause hepatitis) cholesterol and FBC
Describe Acne Rosacea, its features and management.
It is a chronic relapsing/remitting disorder of blood vessels and pilosebasceous units in convex central facial areas typically in fair skinned people. Irritated by alcohol and spices.
Features: red rash typically affecting nose, cheeks and forehead, flushing is often first symptom, telangiectasia are common, later develops into persistent erythema with papules and pustules. Rhinophyma and ocular involvement blephatits
Management:
- avoid irritants and sun overexposure.
- CBT may help with avoiding blushing
- topical azelaic acid + metronidazole, for mild to moderate disease.
- Oral tetracyclines may be used
- rarely isotretinioin and lasers are needed for resistant cases.
Describe Plantar Warts (Verrucas) and its management
Cause by human papilloma virus in keratinocytes. Large con fluent lesions often resist treatment (can last 2 years). They are infectious.
Management: Try topical salicyclic acid or combination therapy such as CPS (Cantharidin, podophyllotoin, Salicyclic acid)
Describe Lichen Planus and its management
Lesions, typically on the flexor aspects of wrists, forearms, ankles and legs, appear purple, pruritic, poly-angular, planar (flat-topped), papules. Occur at any age, and may be outlined by white lacy markings known as Wickham’s striae. Can also cause scarring alopecia.
Management:
- usually persists for 6-18months.
- topical steroids +/- antifungals are first line.
