Dermatology Flashcards
Layers of the skin from superficial to deep?
Epidermis
→ keratin layer
→ granular layer
→ prickle cell layer
→ basal cell layer
Dermoepidermal junction
Dermis
→ papillary dermis
→ reticular dermis
Outline the pathophysiology of acne?
- Androgens increase sebum production
- Sebum and keratin block the pilosebaceous unit leading to swelling and inflammation
- Colonisation of propionibacterium acnes leads to further inflammation
Features of acne vulgaris?
Mild = comedones
Moderate = comedones, pustules, papules
Severe = extensive inflammatory lesions, scarring
Management of acne vulgaris?
Depend on severity of symptoms:
→ benzoyl peroxide
→ topical retinoid
→ topical antibiotics
→ oral antibiotics or contraceptive (females)
→ oral retinoid
List some side effects of isotretinoin?
Teratogenic
Dry lips/mouth
Hair thinning
Low mood
Photosensitivity
Advice for prescribing Dianette for acne vulgaris?
Higher risk of VTE compared to other COCPs
Use for a maximum of 3 months
Advice for prescribing oral antibiotics for acne vulgaris?
Co-prescribe benzoyl peroxide or oral retinoid
Tetracycline is preferred
Use for a maximum of 3 months
Features and management of acne rosacea?
Facial flushing
Pustules, papules
Telangiectasia
Rhinophyma
Triggers e.g. UV, alcohol
Management = brimonidine (flushing), topical ivermectin, topical metronidazole, oral doxycycline
Topical steroid ladder?
Help Every Budding Dermatologist:
Mild = hydrocortisone
Moderate = eumovate (clobestasone butyrate)
Potent = betnovate (betamethasone)
Very potent = dermovate (clobetasol propionate)
Feature of atopic dermatitis (eczema)?
Dry, flaky, itchy skin on flexor surfaces
→ extensors/cheeks in babies
Management of atopic dermatitis (eczema)?
Emollient +/- topical steroid
Feature, cause and management of eczema herpeticum?
Monomorphic “punched out” lesions
Cause = HSV-1 or HSV-2 infection
Management = admission + IV aciclovir
Features, cause and management of impetigo?
Golden, crusted lesions around mouth
Cause = staphylococcus or streptococcus
Management = topical hydrogen peroxide or topical fusidic acid (limited), oral flucloxacillin (extensive)
School exclusion for children with impetigo?
48 hours after starting antibiotics
Types of contact dermatitis and cause?
Irritant = non-allergic reaction to chemical damage
Allergic = type IV hypersensitivity reaction to allergen
Investigation and management of contact dermatitis?
Investigation = patch testing
Management = emollient +/- topical steroid
Feature, cause and management of seborrhoeic dermatitis?
Dry, flaky, itchy skin on sebum-rich areas
Cause = malassezia furfur (yeast)
Management = topical ketoconazole
Feature and management of dermatitis herpetiformis?
Itchy, vesicular rash on extensor surfaces
Management = gluten-free diet, dapsone
Features of plaque psorasis?
Red, scaly plaques on extensors, scalp, trunk, buttocks
Nail changes e.g. pitting, onycholysis
Triggers of plaque psoriasis?
Skin trauma (Koebner phenomenon)
Beta-blockers, NSAIDs, lithium, anti-malarials
Management of plaque psoriasis?
1st line = emollient + topical steroid (OD) + topical vit D analogue (OD)
2nd line = emollient + topical vit D analogue (BD)
3rd line = emollient + topical steroid (BD)
N.B. dithranol (vit A analogue) and coal tar can also be used
Secondary care management of plaque psoriasis?
Phototherapy = narrowband UVB
Systemic therapy = methotrexate
Management of scalp psoriasis?
Topical steroid + softener e.g. salicylic acid
Features and management of guttate psoriasis?
“Tear drop” papules on trunk and limbs
2-4 weeks post-strep infection
Management = self-resolving
Features and management of lichen planus?
Itchy, purple, polygonal, papular rash
Wickham’s striae
Management = topical steroid
Drugs which can cause lichenoid eruption?
Beta-blockers
Gold
Thiazides
Anti-malarials
Features and management of lichen sclerosus?
Mostly elderly women
Genital itch
Atrophy
Scarring
Management = emollients +/- topical steroids
What is erythroderma and most common cause?
Erythema covering > 90% of body surface
Exacerbation of existing skin disease e.g. dermatitis
What is erythrasma and most common cause?
Pink/brown patches in damp areas e.g. groin
Overgrowth of corynebacterium
What is erythema multiforme and most common cause?
Type IV hypersensitivity reaction causing target lesions
HSV infection
What is erythema nodosum and most common cause?
Inflammation of subcut fat causing tender nodules
Group B strep infection
What is erythema ab igne and most common cause?
Reticulated pattern of erythema and hyperpigmentation
Infrared radiation e.g. hot water bottles
Cause of pityriasis rosea vs pityriasis versicolor?
Rosea = HHV-7
Versicolor = malassezia furfur
Features and management of pityriasis rosea?
Initially single herald patch on trunk
Widespread rash of scaly patches follows
Management = self-limiting
Features and management of pityriasis versicolor?
Pink, brown or hypopigmented scaly patches
More noticeable with suntan
Management = ketoconazole shampoo
Features, cause and management of shingles?
Prodromal burning pain over dermatome
Vesicular, blistering rash
Cause = reactivated VZV
Management = aciclovir + paracetamol/NSAIDs
Complications of shingles?
Post-herpetic neuralgia
Ocular issues (CN V1 involvement)
Facial paralysis (CV VII “Ramsay Hunt”)
Outline the shingles vaccination programme?
Offered to anyone aged 71-79
Management of tinea capitis vs tinea corporis vs tinea pedis?
Capitis = topical ketoconazole + oral antifungal
Corporis = oral antifungal
Pedis = topical antifungal (1st line), oral antifungal (2nd line)
Management of fungal nail infection?
Limited = topical amorolfine 5%
Extensive= oral terbinafine
Management of scabies?
All household members should be treated:
1st line = permethrin 5%
2nd line = malathion 0.5%
Management of head lice?
Only treat other household members if symptomatic:
1st line = malathion
Features and management of molluscum contagiosum?
Pearly papules with central umbilication
Management = self-limiting
Features, cause and management of chickenpox?
Prodromal fever
Itchy rash (macular → papular → vesicular)
Cause = VZV
Management = supportive, immunocompromised or peripartum exposure = IV VZV Ig → IV aciclovir if chickenpox develops
School exclusion for children with chickenpox?
Until all lesions are crusted over
Features, cause and management of roseola infantum?
Prodromal high fever
Febrile convulsions
Maculopapular rash
Nagayama spots (uvula/soft palate)
Cause = HHV-6
Management = self-limiting
Features, cause and management of hand, foot and mouth?
Generally unwell e.g. fever
Oral ulcers
Vesicles on palms and soles
Cause = coxsackie A16
Management = supportive
School exclusion for hand, foot and mouth?
No need to stay off if well
Red or purple birthmark that gets darker over time?
Port wine stain
Blotchy pink birthmark that improves over time (except ones on neck)?
Salmon patch
Red, multi-lobed growth presenting in the first month of life and improving over time?
Strawberry naevus
Common newborn rash containing small papules surrounded by an erythematous halo?
Erythema toxicum
Common newborn keratin-filled cysts on face?
Milia
Brown “stuck on” lesions seen in older people?
Seborrhoeic keratosis (basal cell papilloma)
Solitary firm papule originating at site of injury e.g. insect bite?
Dermatofibroma
Features of Lyme disease?
Erythema migrans
Generally unwell e.g. fever
Heart block
Pericarditis
Nerve palsies
Investigations and management of Lyme disease?
Investigations = clinical diagnosis if erythema migrans present, ELISA antibodies to borrelia burgdorferi (1st line)
Management = doxycycline (early disease), ceftriaxone (disseminated disease)
Features and management of urticaria?
Itchy, pink raised skin
“Hives,” “wheals” etc.
Management = non-sedating antihistamine
Examples of sedating vs non-sedating antihistamines?
Sedating = chlorpheniramine (Piriton), promethazine, cyclizine
Non-sedating = loratadine, fexofenadine, cetirizine
Cause of bullous pemphigoid vs pemphigus vulgaris?
Bullous pemphigoid = antibodies against hemidesmosomal proteins
Pemphigus vulgaris = antibodies against desmoglein 3
Features and management of bullous pemphigoid?
Itchy, tense sub-epidermal blisters
Heal without scarring
Nikolsky’s sign -ve
No mucosal involvement
Management = oral steroids
Skin biopsy feature of bullous pemphigoid?
IgG and C3 at the DEJ
Features and management of pemphigus vulgaris?
Painful, flaccid epidermal blisters
Heals with scarring
Nikolsky’s sign +ve
Mucosal involvement
Management = oral steroids
Skin biopsy feature of pemphigus vulgaris?
Acantholysis
Features, cause and management of AIP?
GI upset
Motor neuropathy
Depression
Red urine
Cause = porphobilinogen deaminase deficiency
Management = IV haem arginate
Features, cause and management of PCT?
Photosensitive rash
Hypertrichosis
Hyperpigmentation
Cause = uroporphyrinogen decarboxylase deficiency
Management = chloroquine, venesection
Most common causes of SJS/TEN?
Antibiotics
Antiepileptics
Allopurinol
NSAIDs
Difference between SJS vs TEN?
SJS = < 10% body surface
TEN = > 30% body surface
N.B. 10-30% is SJS/TEN overlap syndrome
Features and management of SJS/TEN?
Widespread erythematous rash
Vesicles and bullae
Nikolsky’s +ve
Sytemically unwell
Management = admission + supportive manegement + IV Igs (TEN)
Classification and features of burns?
Superficial epidermal (1st degree) = red, painful, dry
Partial thickness (2nd degree)
→ superficial dermal = pink, painful, blistered
→ deep dermal = white +/- patches of erythema, loss of sensation, painful to deep pressure
Full thickness (3rd degree) = white, brown or black, no pain
SCC precursors?
Actinic keratosis
Bowen’s disease
Features and managemnt of actinic keratosis?
Small scaly patches on sun-exposed skin
Management = 5-FU, topical diclofenac, imiquimoid, cryotherapy, curettage and cautery
Features and management of Bowen’s disease?
Pink scaly patch on sun-exposed skin
Management = 5-FU, cryotherapy, excision
Features and management of SCC?
Rapidly growing lesion
Scale, ulceration, bleeding
PMH chronic sun exposure
Management = excision with 4mm margin if < 20mm, excision with 6mm margin if > 20mm, Mohs surgery if on cosmetically important site e.g. face
Epithelial tumour which spontaneously regresses. Can be mistaken for SCC?
Keratoacanthoma
Features and management of BCC?
Slowly growing lesion
Central ulceration
Pearly rolled edges, telangiectasia
PMH intermittent sun exposure
Management = excision with 4mm margin if < 20mm, excision with 6mm margin if > 20mm, Mohs surgery if on cosmetically important site e.g. face
ABCDE of worrying skin lesions?
Asymmetry
Border irregularity
Colour variation
Diameter > 7mm
Evolving
Types of malignant melanoma?
Superficial spreading (most common)
Nodular
Lentigo maligna
Acral lentiginous
Investigation and management of melanoma?
Investigation = excision biopsy
Management = surgery dependent on Breslow thickness
Margins of melanoma excision?
Breslow thickness:
→ 0-1mm = 1cm margin
→ 1-2mm = 1-2cm margin
→ 3-4mm = 2-3cm margin
→ > 4mm = 3cm margin
