GP - Derm Flashcards
What are the clinical features of eczema?
- Itchy, erythematous rash exacerbated by repeated scratching
- Infants = face/trunk
- Young children = extensor surfaces
- Older children = flexor surfaces/creases of face and neck
Describe the pathophysiology of eczema
- Defects in the normal continuity of the skin barrier
- Provides entrance for irritants/microbes/allergens
- Inflammation in skin
What is the management for eczema?
Create artificial barrier using emollients
- Thin = creams (E45/diprobase/cetraben/epaderm)
- Thick/greasy = ointments (hydromol/diprobase/cetraben/epaderm)
- Avoid hot baths/scratching/certain soaps
- Topical steroids (flares)
- Wet wraps (flares)
What steroids are used for eczema?
Mild = hydrocortisone
Moderate = betamethasone/clobetasone
Potent = fluticasone propionate/betamethasone valerate
Very potent = clobetasol propionate
What are risk factors for psoriasis?
- Genetics = HLA-B13/HLA-B17/HLA-Cw6
- Environment (skin/trauma/stress)
- Improves in sunlight
What are the clinical features of psoriasis?
-Red/scaly patches on skin
- Pitting/onycholysis
- Arthritis
- Plaque psoriasis = most common = well-demarcated red scaly patches affecting extensor surfaces/sacrum/scalp
What are the subtypes of psoriasis?
- Plaque psoriasis (most common - typical presentation)
- Flexural psoriasis (skin is smooth)
- Guttate psoriasis (transient rash triggered by strep infection –> teardrop lesions)
- Pustular psoriasis (palms/soles)
What are exacerbating factors for psoriasis?
- Trauma
- Alcohol
- Drugs (beta blockers/lithium/antimalarials/NSAIDs/ACEis/infliximab)
- Withdrawal of systemic steroids
- Strep infection (may trigger guttate psoriasis)
What is the management for psoriasis?
- Regular emollients
- Potent corticosteroid + vitamin D analogue
- Coal tar preparation
- Short acting dithranol
- Phototherapy
- Systemic therapy e.g. methotrexate
What are complications of psoriasis?
- Psoriatic arthropathy
- Increased risk of metabolic syndrome
- Increased risk of CVD/VTE
What is Koebner phenomenon?
Psoriasis develops in areas of trauma or friction
What is intertrigo?
Rash in flexures e.g. behind ears/folds of neck/under arms/finger webs due to skin-to-skin friction intensified by heat and moisture
What are risk factors for intertrigo?
- Obesity
- Hyperhidrosis
- Age
- Diabetes
- Smoking
- Alcohol
What are the clinical features of intertrigo?
- Inflamed/reddened/uncomfortable skin
- Moist/macerated skin leading to fissuring and peeling
- Foul odour (if secondary bacterial infection e.g. pseudomonas)
What are some infections that can cause intertrigo?
- Thrush (candida albicans)
- Tinea cruris/athlete’s foot
- Impetigo (staph aureus/strep pyogenes)
- Boils (staph aureus)
- Folliculitis (staph aureus)
What are the investigations for intertrigo?
- Swab for culture/microscopy (bacterial/fungal)
- Skin biopsy for histopathology
What is the management for intertrigo?
- Treat underlying cause
- Zinc oxide paste
- Physical exertion followed by bathing/completely drying skin flexures
- Antiperspirant cream/powder
- Topical abx/antifungals
- Low potency steroid creams
What is tinea and give some examples?
Dermatophyte fungal infections
- Tinea capitis - scalp (scalp ringworm)
- Tinea corporis - trunk/legs/arms (ringworm)
- Tinea pedis - feet (athlete’s foot)
- Tinea cruris - groin
What are the features of tinea?
- Scarring alopecia (tinea capitis)
- Well-defined erythematous lesions with pustules/papules
- Itchy/peeling skin
What is the management for tinea?
- Anti-fungal creams (clotrimazole)
- Anti-fungal shampoos (ketoconazole)
- Anti-fungal oral medications (fluconazole)
- Topical steroid
What is pityriasis versicolor and what causes it?
- Common yeast infection of the skin
- Yeast = malassezia
Describe the epidemiology of pityriasis versicolor
- More common in men
- More common in hot/humid climates (people that perspire heavily)
What are the clinical features of pityriasis versicolor?
- Flaky discoloured patches on the trunk/neck/arms
- Usually asx but may be itchy
What is the management for pityriasis versicolor?
- Topical antifungals (selenium sulfide shampoo; topical econazole/ketoconazole cream/shampoo; terbinafine gel)
- Oral antifungals (itraconazole/fluconazole)
What are some inducible features of urticaria?
- Cold urticaria
- Cholinergic urticaria
- Contact urticaria
- Sun urticaria
- Heat urticaria
What is the management for urticaria?
- Non-sedating antihistamine e.g. cetirizine/loratadine
- Sedating antihistamine e.g. chlorphenamine
- Prednisolone (severe/resistant episodes)
- Avoidance of trigger factors
What is the cause of chickenpox and how is it spread?
- Varicella zoster virus
- Shingles = reactivation of dormant virus in dorsal root ganglion
- Respiratory droplets
What are the clinical features of chickenpox?
- Fever initially
- Itchy rash that starts on head/trunk = macular –> papular –> vesicular
What is the management for chickenpox?
- Calamine lotion
- School exclusion until all lesions are dry and have crusted over
- Varicella zoster immunoglobulin (VZIG) if immunocompromised/newborns
What are complications of chickenpox?
- Secondary bacterial infection (cellulitis/group A strep/necrotising fasciitis) –> DO NOT GIVE NSAIDS
- Pneumonia
- Encephalitis
Describe the typical features of measles
- Fever
- Coryzal sx
- Conjunctivitis
- Koplik spots (blue/white spots in cheek)
- Rash starts behind ears and spreads
What is the management for measles?
- Supportive
- Consider admission in immunosuppressed/pregnant patients
- Notify public health
- MMR vaccine (1 year and 3 years)
What are the complications of measles?
- Otitis media
- Pneumonia
- Encephalitis
- Febrile convulsions
What is molluscum contagiosum and who is it most common in?
- Skin infection caused by molluscum contagiosum virus (MCV)
- Children (often with atopic eczema) around 1-4 years
What are the clinical features of molluscum contagiosum?
- Pink/white papules with central umbilication/dimple
- Lesions appear in clusters on the body (NOT palms/soles)
What is the management for molluscum contagiosum?
- Self-limiting
- Spontaneous resolution within 18 months
- Avoid sharing towels/clothing/baths as lesions are contagious
- Don’t scratch
Treatment (not usually recommended - only if troublesome):
- Squeezing/piercing lesions following a bath
- Cryotherapy
- Topical corticosteroid/abx if eczema/inflammation around lesions
What are the features of herpes simplex virus?
- Gingivostomatitis (blisters on lips/canker sores in mouth)
- Cold sores
- Painful genital ulceration
What is the management for herpes simplex virus?
- Oral/topical aciclovir
- Chlorhexidine mouthwash
What is the guidance for pregnant patients with herpes simplex virus?
- Elective c-section at term if primary attack occurs >28 weeks
- Recurrent herpes = suppressive therapy to reduce risk of transmission
What is shingles?
Herpes zoster infection caused by reactivation of varicella zoster virus - virus lies dormant following primary infection (chickenpox) in dorsal root/cranial nerve ganglia
What are the risk factors for shingles?
- Increasing age
- HIV
- Immunosuppression
What are the clinical features of shingles?
- T1-L2 dermatomes most affected
- Prodromal period = burning pain/fever/headache/lethargy
- Erythematous, macular rash –> becomes vesicular
What is the management for shingles?
- Analgesia
- Infectious until vesicles have crusted over
- Antivirals within 72 hours (aciclovir/famciclovir/valaciclovir)
What are the complications of shingles?
- Post-herpetic neuralgia (most common)
- Herpes zoster ophthalmicus
- Herpes zoster oticus (Ramsay Hunt syndrome)
What are the clinical features of pityriasis rosea?
- May have recent viral infection sx
- Herald patch (usually on trunk)
- Erythematous, oval, scaly patches (fir tree appearance)
What is the management for pityriasis rosea?
Self-limiting = usually disappears after 6-12 weeks
What is impetigo and what is it caused by?
- Superficial bacterial skin infection
- Usually staph aureus or strep pyogenes
- Common in children (especially in warm weather)
What are the clinical features of impetigo?
- Golden, crusted skin lesions typically found around mouth/face/flexures/limbs
- Very contagious
What is the management for impetigo?
- Hydrogen peroxide 1% cream (first line)
- Exclusion from school until lesions are crusted/healed or 48 hours after commencing abx treatment
- Topical abx = fusidic acid/mupirocin
- Extensive disease = oral flucloxacillin/erythromycin
What is cellulitis and what is it caused by?
- Bacterial infection affecting dermis and deeper subcutaneous tissues
- Strep pyogenes (most common) or staph aureus
What are the clinical features of cellulitis?
- Unilateral
- Usually on shins
- Erythema
- Blisters/bullae (more severe)
- Swelling
- Systemic sx = fever/malaise/nausea
What criteria is used for cellulitis?
Eron classification:
- Class I = no signs of systemic toxicity
- Class II = systemically unwell or has a comorbidity which may complicate/delay resolution of infection
- Class III = significant systemic upset e.g. acute confusion/tachycardia/tachypnoea/etc. that may interfere with response to treatment
- Class IV = sepsis syndrome/severe life threatening infection e.g. necrotising fasciitis
What is the management for mild/moderate cellulitis?
Oral abx = flucloxacillin (first line)/clarithromycin/erythromycin (pregnancy)/doxycycline
What is the admissions criteria for cellulitis?
- Eron class III or IV
- Severe/rapidly deteriorating cellulitis
- <1 year or frail
- Immunocompromised
- Has significant lymphoedema
- Has facial cellulitis/periorbital cellulitis
What is the management for severe cellulitis?
- Admit
- Oral/IV co-amoxiclav/clindamycin/cefuroxime/ceftriaxone
What are the clinical features of acne rosacea?
- Typically affects nose/cheeks/foreheads
- Flushing
- Telangiectasia –> persistent erythema with papules/pustules
- Rhinophyma
- Blepharitis
- Exacerbated by sunlight
What is the management for acne rosacea?
- High factor suncream
- Topical brimonidine (flushing - alpha-adrenergic agonist)
- Topical ivermectin/metronidazole/azelaic acid (mild-moderate papules/pustules)
- Topical ivermectin + oral doxycycline (moderate-severe papules/pustules)
Describe the pathophysiology of acne vulgaris
Chronic inflammation/blockage of pilosebaceous units, increased sebum production and trapping of keratin
What are the clinical features of acne vulgaris?
- Comedones (whitehead/blackhead)
- Papules/pustules
- Nodules/cysts
- Ice-pick scars/hypertrophic scars
What is the management for mild to moderate acne vulgaris?
- Topical benzoyl peroxide
- Topical retinoid (adapalene/tretinoin)
- Topical abx (clindamycin)
What is the management for moderate to severe acne vulgaris?
- Topical benzoyl peroxide
- Topical retinoid (adapalene/tretinoin)
- Topical abx (clindamycin)
- Oral abx (lymecycline/doxycycline)
- Topical azelaic acid
- COCP (co-cyprindiol - Dianette)
- Oral retinoid (isotretinoin = roaccutane) - specialists only
What are the side effects of roaccutane (isotretinoin)?
- Highly teratogenic
- Dry skin/lips
- Photosensitivity of skin
- Depression/anxiety/aggression/suicidal ideation
- Stevens-Johnson syndrome and toxic epidermal necrolysis
What are head lice caused by?
Parasitic insect - Pediculus capitis
What are the clinical features of head lice?
Itching/scratching on scalp 2-3 weeks after infection
What is the management for head lice?
- Malathion
- Wet combing
- Dimeticone
- Isopropyl myristate
- Cyclomethicone
What is scabies caused by?
Sarcoptes scabiei
What are the clinical features of scabies?
- Widespread pruritus
- Linear burrows on side of fingers/interdigital webs/flexor aspects of wrist/face/scalp
- Excoriation/infection (due to scratching)
What is the management for scabies?
- Permethrin 5% (first line)
- Malathion 0.5%
- Treat all household/close physical contacts even if asx
- Avoid close physical contact with others until treatment complete
What is crusted scabies?
- a.k.a Norwegian scabies
- Seen in patients with suppressed immunity (especially HIV)
- Management = ivermectin + isolation
What is exanthem?
Widespread rash usually accompanied by systemic sx e.g. fever/malaise/headache usually caused by a virus
What are common causes of exanthems?
Viral infections:
- Chickenpox (varicella)
- Measles (morbillivirus)
- Rubella (rubella virus)
- Roseola herpes virus 6B
- Erythema infectiosum (parvovirus B19)
What is the management for exanthems?
- Supportive management
- Paracetamol
- Emollients
What chronic conditions may cause pruritus?
- Liver disease
- Renal disease
- Anaemia
- Diabetes
- Hyper/hypothyroidism
- Cancer
What are the most common types of malignant melanoma?
- Superficial spreading (most common)
- Nodular (most aggressive)
- Lentigo maligna
- Acral lentiginous
What are the risk factors for melanomas?
- Immunosuppression
- Numerous moles
- Family history
- Exposure/overexposure to UV light
What are the classic appearances of melanomas?
ABCDE:
- Asymmetry
- Border irregularities
- Colour variation
- Diameter >7mm
- Enlargement
Nodule = EFG
- Elevated
- Firm to touch
- Growing
What are the clinical features of melanomas?
- New/changed skin lesion (colour/shape/size/ulcerations/pruritus/bleeding)
- Nausea/vomiting/loss of appetitie/fatigue
What is the investigation and management for malignant melanomas?
Investigation = sentinel node biopsy
Management = excision biopsy
What are the complications of melanomas?
Metastasis to lymph nodes/skin/subcutaneous tissue/lungs/liver/brain
What is the most common type of skin cancer?
Basal cell carcinoma
What are the main causes of basal cell carcinoma?
- UV radiation
- Gorlin syndrome (mutation of PTCH1 gene)
What are the most common types of basal cell carcninoma?
- Nodular (most common)
- Infiltrative
- Micronodular
- Morpheaform
- Superficial
What are the classic appearances of basal cell carcinomas?
- Nodular = white circular cystic pigmented nodule
- White/yellow lesion
- May be waxy
- Erythematous plaque
What are the clinical features of basal cell carcinomas?
- Sun-exposed areas e.g. face/neck/scalp
- Newly discovered lesion
- Doesn’t heal within 4 weeks
- Dimpled at midpoint
- Grows slowly
- May bleed
- Painless/may itch
- Telangiectasia
- Ulcerated
What is the investigation for basal cell carcinomas?
Biopsy and histology = basal cells form clusters (islands) with peripheral palisading nuclei
What is the management for basal cell carcinomas?
- Topical 5-fluorouracil/imiquimod
- Srugical excision
- Curettage
- Cryotherapy
- Radiotherapy
RARELY METASTASISES
What are the risk factors for squamous cell carcinomas?
- Overexposure to UV light
- Actinic keratoses/Bowen’s disease
- Immunosuppression
- Smoking
- Long-standing leg ulcers
What are the clinical features of squamous cell carcinomas?
- Sun exposed sites e.g. head/neck/arms
- Rapidly expanding, painless, ulcerate nodules
- May have cauliflower-like appearance
- Bleeding
What are the investigations for squamous cell carcinomas?
- Biopsy
- CT
- MRI
What is the management for squamous cell carcinomas?
- Surgical excision
- Topical immunomodulators (e.g. tacrolimus)
- Chemotherapy/radiotherapy
What are the complications of squamous cell carcinomas?
Metastasis
What are the risk factors for venous ulcers?
Most common type of leg ulcer
- Previous DVT
- Reduced mobility e.g. OA/leg injury/obesity/paralysis
- Varicose veins
- Leg surgery
What are the clinical features of venous ulcers?
- Typically seen above medial malleolus
- Pain/itching/swelling in affected leg
- Discoloured/hardened skin around ulcer
- Offensive discharge
What is the investigation for venous ulcers?
ABPI in non-healing ulcers:
- Assess for poor arterial flow which could impair healing
- Normal = 0.9-1.2
What is the management for venous ulcers?
- Compression bandaging (4 layer)
- Oral pentoxifylline (peripheral vasodilator)
- Abx if infected
What is a port-wine stain?
- Capillary malformation seen at birth
- Flat and dark red/purple
- Usually requires no treatment
What is the most common type of contact dermatitis?
Irritant contact dermatitis - non-allergic reaction due to weak acids/alkalis e.g. detergents
What is the most common cause of cutaneous warts?
Viral - HPV
What are common causes of folliculitis?
- Infection e.g. staph aureus/candida albicans/herpes zoster
- Occlusions e.g. paraffin-based ointments
- Irritation
- Skin diseases
- Overuse of topical steroids
