Dermatology Flashcards
How to describe skin lesion
Site
Colour
Associated changes
Morphology
How to describe a pigmented skin lesion
Asymmetry Border Colour Diameter Evolution `
Psychosocial effects of eczema and acne
Self-conscious Social isolation Embarrassed Cover up Anxiety
Structure of skin
Epidermis
Dermis
Subcutaneous tissue
Epidermis
Physical barrier
Stratum corneum is keratanised and constantly replaced
Thicker stratum corneum on hands and feet
Contains Langerhans cells - defence against pathogens
Dermis
Thick layer made of collagen, elastin and fibrillin
Gives flexibility and strength
Contains nerve endings, glands, hair follicles and blood vessels
Malignant Melanoma
Asymmetrical Border: irregular Colour: non-uniform Diameter > 6mm Evolving / Elevation
Risk factors for malignant melanoma
Sunlight: esp. intense exposure in early years Fair-skinned (Low Fitzpatrick Skin Type) ↑ no. of common moles \+ve FH ↑ age Immunosuppression
Classification of malignant melanomas
Superficial spreading - 80% Lentigo Maligna Acral Lentiginous Nodular Amelanotic - atypical appearance with delayed dx
Lentigo Maligna
Elderly pts
Face or scalp
Acral Lentiginous
Asians/blacks
Palms, soles
Nodular Melanoma
All sites:
Younger age, new lesion
Invade deeply and metastasis early = poor prog
Common metastases of malignant melanoma
Liver
Eye
Mx of malignant melanoma
Excision + secondary margin excision depending on depth
± lymphadenectomy
± adjuvant chemo
Poor prognostic indicators of malignant melanoma
Male sex (more tumours on trunk cf females)
↑ mitoses
Satellite lesions (lymphatic spread)
Ulceration
Squamous Cell Carcinoma
Ulcerated lesion with hard, raised everted edges
Sun exposed areas
May arise in chronic ulcers: Marjolin’s Ulcer
Basal cell carcinoma
Commonest skin cancer
- Rodent ulcers
- Pearly nodule with rolled telangiectactic edge
- May ulcerate
- Typically on face in sun-exposed area
Behaviour:
Very rarely metastasise
Locally invasive
Mx: if closed to eye
Excision
Cryo/radio may be used.
Evolution and Mx of SCC
Solar/actinic keratosis → Bowen’s → SCC
Lymph node spread is rare
Rx:
Excision + radiotherapy to affected nodes
Actinic Keratoses
Irregular, crusty warty lesions.
Pre-malignant
Mx: for cosmetic effect Cautery - Cryotherapy - 5- flourouracil - Photodynamic phototherapy
Bowen’s Disease
Red/brown scaly plaques
SCC in situ
Psoriasis risk factors and pathology
Age: peaks in 20s and 50s
FHx
Type IV hypersensitivity reaction
- Epidermal proliferation
- T-cell driven inflammatory infiltration
Psoriatic histology
Acanthosis: thickening of the epidermis
Parakeratosis: nuclei in stratum corneum
Psoriatic triggers
Stress Infections: esp. streps Skin trauma Drugs: β-B, Li, anti-malarials, EtOH Smoking
Signs of psoriasis
Symmetrical well-defined red plaques with silvery scale
Distribution:
Extensors: elbows, knees
Flexures - in children(
Scalp, behind ears, navel, sacrum
Psoriatic arthritis:
Mono-/oligo-arthritis: DIPs commonly involved
Asymmetrical
Psoriatic spondylitis
Psoriatic nail changes
Pitting
Onycholysis
Subungual hyperkeratosis - excessive skin cells that accumulate between the nail and the nail bed
Mx of psoriasis
Education: Avoid triggers Soap Substitute Emollients Topical Therapy: Vit D3 analogue: Steroids: e.g. betamethasone
Tar: mainly reserved for in-patient use
UV Phototherapy
Non-Biologicals
- Methotrexate
- Ciclosporin
Atopic dermatitis presentation
Extremely itchy
Poorly demarcated rash
Acute: oozing papules and vesicles
- Subacute: red and scaly
- Chronic eczema → lichenification
- Skin thickening with exaggeration of skin markings
Commonly on flexors, cheeks and around eyes
PMHx- atopy
FHx
Pathophysiology of atopic dermatitis
TH2 driven inflammation with ↑IgE production
Adult Seborrhoeic Dermatitis
Red, scaly, rash
Cause: overgrowth of skin yeasts
Location: scalp (dandruff), eyebrows, cheeks, nasolabial folds
Rx: mild topical steroids / antifungal e.g. Daktacort: miconazole + hydrocortisone
Mx of atopic dermatitis
Education: Avoid triggers
Emollients
Topical Steroids
2nd line Therapies:
- Topical tacrolimus
- Phototherapy
- Ciclosporin or azathioprine
Topical Steroids
1% Hydrocortisone: face, groins
Betnovate
Dermovate: very strong, brief use on thick skin - Palms, soles
Surface features
Scale - build up of keratin
Crust - dried exudate
Excoriation - linear erosions from scratching
Erosions/ulceration
Papule
Small lump < 5mm
Nodule
Larger lump - 5 - 10mm
Vesicle
Small water blister
Bulla
Large water blister
Pustule
Pus filled vesicle
Telangiectasia
Thead veins
Alopecia
Hair loss or thinning
Macule
Non palpable area of discolouration < 10mm
Patch
Non palpable area of discolouration > 10mm
Plaque
Elevated area > 2cm
Erosion
Palpable, flat-topped area- 1cm
Ulcer
Palpable, flat topped area- 2cm
Lichenification
Loss of epidermis - superficial
Loss of epidermis and dermis - deep
Thickening
Comedone
Black head - open or closed
Erythema multiform
Target appearance
Multiple coalescing erythematous patches
Tinea
Superficial mycosis caused by dermatophytes - fungi
Presentation of tinea
Round scaly lesion
Itchy
Central clearing with raised annular ring
Scalp, body, foot, groin, nails
Ix and Mx for Tinea corporis
Ix: Skin sample and fungal microscopy
Mx:
Topical antifungals:
- Terbinafine
- Imidazole - OTC
Inflammation:
Topical corticosteroid - hydrocortisone 1% - should not be used alone
Severe: Oral antifungal if there is:
+ve fungal microscopy or culture
Strong clinical suspicion
Arrange repeat skin sampling
Conservative mx of tinea corporis
Loose fitting clothes made of cotton
Good hygiene - wash affected area daily and dry thoroughly
Do not share towels
Wash clothes and bed linen to remove fungal spores
Onychomycosis
Starts at edges of nails
Nail discolours and lifts off
White/yellow opaque streak on one side of nail
Mx:
Antifungal nail cream -
Apply for 12 months but doesn’t always work
Nail softening cream -
2 weeks to soften nail so infection can be scraped off the nail
If severe - oral antifungals for 6 months or remove
Tinea versicolor
- Fungus interferes with the normal pigmentation of the skin - small, discoloured patches.
- May be lighter or darker in colour
- Commonly affect the trunk and shoulders
Impetigo
Contagious superficial skin rash caused by S. aureus
Presentation:
Age: peak @ 2-5yrs
Honey-coloured crusts on erythematous base
Common on face
Mx
Mild: topical Abx - fusidic acid
More severe: flucloxacillin PO
Pityriasis Rosea
Presents with inflamed skin patch first.
Followed by further skin eruptions
Associated with a sore throat and a cold before sin changes occur
Herald patch precedes rash, mainly on the trunk
Acne Vulgaris Mx
Pt. education - wash face and moisturise twice a day
Mild: topical therapy
- Benzoyl peroxide
Moderate
- Topical benzoyl peroxide + oral Abx (doxy or erythro)
Severe:
- Isotretinoin (vitamin A analogue) - Retinol
Side effects of retinol
Teratogenic, hepatitis, ↑lipids, depression, dry
skin, myalgia
Suicidal thoughts
Monitor: LFTs, lipids, FBC
May try Dianette (COCP) in women
- only give if scarring and needs dermatologist review
Urticaria
Wheals ± angioedema and anaphylaxis
Rapid onset after taking drug
- treat anaphylaxis and remove trigger
- non sedating anti-histamine - cetirizine
- sedative antihistamine - chlorphenamine
Parvovirus
Slapped cheek
Erysipelas
Sharply defined superficial infection by S. pyogenes
- Often affects the face
- High fever + ↑ WCC
Mx
- Benpen IV
- Pen V and fluclox PO
Lichen Planus
Flexors: wrists, forearms, ankles, legs
Purple and Pruritic papules on palms, soles and flexors
Lacy white marks
Mx: topical steroids - clobetasonr butyrate
Scabies
Highly contagious: spread by direct contact
- Female mite digs burrows and lays eggs
Presentation:
Burrows: short, red line, block dot
Hypersensitivity rash: eczematous, vesicles
Extremely itchy → escoriation
Particularly affects the finger web spaces (esp. 1st)
Also: axillae, groin, umbilicus
Mx Permethrin cream: applied from neck down for 24hrs, 2 doses 2 weeks apart to all close contacts as well 2nd line: Malathion 3rd line: oral ivermectin Treat all members of the household
Wash bed sheets and curtains
Treatment of impetigo
Hydrogen peroxide 1% cream
Topical antibiotics - fusidic acid
If extensive - flucloxacillin or erythromycin if allergic
Children should not go to school until 48 hours after start of abx
Types of acne
Comedonal - open or closed
Inflammatory - papules and pustules
Nodulocystic - nodules, cysts and scars often neck and trunk
Acne fulminans - severe acne associated with fever, myalgia and arthralgia
Ice pick scarring
Irregular deep pitted lesions due to acne
Not due to picking or scratching
Acanthosis nigricans causes
T2DM GI cancer Obesity PCOS Acromegaly Cushing's disease Hypothyroidisim COCP
