1. Dermatology Phase 2A Revision 24th April 2015 Ashy Rengit
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2. Topics Acne Eczema Psoriasis Skin ulceration Skin cancer Infections
Venous, arterial, neuropathic, infective, traumatic, vasculitic
Skin cancer
Squamous cell carcinoma, basal cell carcinoma, melanoma
Infections
Cellulitis, necrotising fasciitis
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3. Acne: Basic Science Definition Epidemiology Pathophysiology
Inflammation of pilosebaceous skin unit
Epidemiology
Often pubertal
Commonly (not always) ↓ with age
Pathophysiology
Bacterium
Staphylococcus epidermidis
Pityrosporum yeast
Propionibacterium acnes
Follicular hyperkeratinisation + pilosebaceous duct obstruction
Increased production + impaired flow of sebum
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4. Acne: Subtypes Acne vulgaris Acne Rosacea Most common type
(ref: clinical presentation)
Acne Rosacea
Affects mostly women aged 30+
Red rashes on nose, cheeks, forehead & chin
Blackheads are unlikely
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5. Acne: Subtypes Acne Conglobata Acne Fulminans Most severe subtype
Commonly found in males
Multiple interconnected large lesions (face, back, chest, upper arms & thighs)
Acne Fulminans
Usually found in young men
Scarring (disfigurement)
Ulcers and cysts
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6. Acne: Subtypes Gram-negative Folliculitis Rosacea Fulminans
Bacterial infection associated with longterm Acne vulgaris (antibiotic) treatment
Associated with pustules and cysts
Rosacea Fulminans
Aka Pyoderma Faciale
20 to 40 year old females
Large, painful nodules/ pustules (scarring)
May occur without previous history of acne
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7. Acne: Clinical Presentation
History
Demographic: puberty
PMH: PCOS (polycystic ovarian syndrome), Cushing’s syndrome, prolactinoma
Acute onset, skin greasy/ painful
Examination
Papules
Solid, raised lesion with no fluid
Pustules
Solid, raised lesion containing fluid or pus
Blackheads
Closed comedones – oxidation of melanin pigment
Whiteheads
Open comedones
Nodules
Solid, raised lesion with no fluid (larger than papules)
Cysts
Fluid filled sac beneath the skin
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8. Acne: Management Investigations Treatment BLOOD URINE IMAGING
Luteinising hormone levels (↑ LH:FSH in PCOS)
Prolactin (↑ in prolactinoma)
Sex-hormone binding globulin
Testosterone
17-OH-progesterone (Congenital adrenal hyperplasia)
URINE
24 hour urinary cortisol (↑ in Cushing’s syndrome)
IMAGING
Pelvic ultrasound (ovarian cysts, PCOS)
Treatment
Mild/ moderate acne
Non-greasy cosmetics/ creams
OTC benzoyl peroxide/ azelaic acid
Moderate/ severe acne
Topical antibiotic e.g. Clindamycin
(blocks bacterial ribosomes)
Vit. A derivatives (retinoin)
Severe inflammatory acne OR failed topical treatment
Systemic antibiotics e.g. erythromycin or oxytetracycline
Severe acne
Oral vitamin A (isoretinoin)
SE: Teratogenic, hyperlipidaemia
Female: should take contraceptive pill or cyproterone acetate (antigonadotropin)
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9. Eczema: Basic Science Definition Pathophysiology of the subtypes
Pruritic (itchy) papulovesicular (papule – solid raised lesion, vesicle – filled with fluid) skin reaction to endogenous or exogenous agents
Pathophysiology of the subtypes
Irritant eczema: prolonged skin contact with cell-damaging irritant (e.g. ammonia)
Contact eczema: Type 4 delayed hypersensitivity reaction (e.g. perfumes or latex)
Atopic eczema
Impaired epidermal barrier function due to structural abnormality (increased sensitivity)
Immune function disorder (inflammatory response to environ by Langerhans and T cells)
Seborrhoeic eczema (Pityrosporum yeast mediated)
Varicose eczema: Increased venous pressure in lower limbs
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10. Eczema: Subtypes Contact & Irritant Atopic Often a well-localised rash
Acute inflammation
Autosensitisation possible (spread to other sites)
Atopic
Acute inflammatory rash with dry and scaly patches
Common on face and flexures
(elbows and knees)
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11. Eczema: Subtypes Seborrhoeic Pompholyx
Yellow, greasy scales on erythematous plaques
Nasolabial folds, eyebrows, scalp and presternal area
Pompholyx
Acute and recurrent
Painful vesiculobulbous eruption
Palms and soles
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12. Eczema: Subtypes Varicose Nummular Eczema in lower limbs
Associated with marked varicose veins
May spread to forearms
Nummular
Coin shaped rashes
On legs and trunk
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13. Eczema: Subtypes Asteatotic History on presentation Examination
Dry patterned patches
Often occurs in the elderly
History on presentation
Severe itching
Heat, tenderness, redness
Occupational exposure e.g. bleach
Family history of atopy e.g. asthma
Examination
Acute
Poorly demarcated dry scaly patches (red and inflamed)
Papules/ vesicles with exudation and crusting (scratch marks)
Chronic
Thickened epidermis (lichenification/ fissures)
Change in pigmentation
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14. = WISKOTT-ALDRICH SYNDROME
Eczema: Management
Investigations
SKIN PATCH TESTING
Contact dermatitis
Diluted allergen applied to part of skin
After 48 hours – red raised lesion
TESTING IgE LEVELS
Not used routinely or currently recommended
SKIN SWAB
Infected lesions
Commonly Staph. aureus, Herpes simplex (life-threatening) and Molluscum contagiosum
*Eczema + Thrombocytopenia (haematological malignancy)
= WISKOTT-ALDRICH SYNDROME
Treatment
Irritant or contact dermatitis
Avoid precipitant/ protection (gloves)
Atopic dermatitis
Avoid precipitant
Emollient creams and soaps
Low potency steroids/ antihistamines
Tacrolimus (calineurin inhibitor) if severe
Systemic immunosuppression/ phototherapy as a last resort
Seborrhoeic dermatitis
1% hydrocortisone cream + antifungal (ketoconazole shampoo for scalp)
Pompholyx
Topical steroid (systemic if severe)
Potassium permangante salts
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15. Psoriasis: Basic Science
Definition
Chronic inflammatory skin disease that is often relapsing/ remitting
May be complicated by arthritis
Can be disfiguring (psychosocial complications)
Epidemiology
Peak age of onset → 20 years
Aetiology & Pathophysiology
Unknown causes: genetic ? Environmental – strep. infections? Drugs – antimalarial agents, lithium, beta-blockers ?
Rapid cell turnover mediated by lymphocytic cytokines
→ Excessive proliferation of epidermal cells
Upward migration of immature keratinocytes (silver plaque appearance)
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16. Psoriasis: Subtypes Discoid/ nummular Flexural
Symetrical well-demarcated erythematous plaques
Silver scales on extensor surface (knee, elbows, scalp, sacrum)
Flexural
Less scaly plaques
Flexures (axilla, groin, perianal, genital)
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17. Psoriasis: Subtypes Guttate Palmoplantar Small ‘teardrop’ lesions
Trunk & limbs
Associated with Strep. (sore throat)
Palmoplantar
Erythematous plaques with pustules
Smoking, middle-aged, female, autoimmune thyroid
S- ynovitis
A- cne
P- ustulosis
H- yperostosis
O- steitis
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18. Psoriasis: Subtypes Generalised Pustular History
Pustules (limbs/ torso)
Hyperparathyroidism
History
Itching/ tenderness
AUSPITZ PHENOMENON
Pinpoint bleeding with removal of scales
KOEBNER PHENOMENON
Skin lesions develop at sites of trauma/ scarring
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19. Psoriasis: Clinical Presentation
Nails
Joints
(seronegative arthritis)
Monoarthritis
Distal asymmetrical oligoarthritis (interphalangeal)
Dactylitis (flexor tenosynovitis)
Rheumatoid arthritis-like
Arthritis mutilans
Ankylosing spondylitis
Pitting
Onycholysis
Nail lifted off nailbed
Subungual hyperkeratosis
(salmon patch)
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20. Psoriasis: Management
Investigations
GUTTATE
Anti-streptolysin-O-titre
Throat swab
FLEXURAL
Skin swab (Ddx: candidiasis ?)
NAIL
Onychomyosis (fungal infections)
JOINT
Rheumatoid factor (negative)
Radiographs
distal interphalangeal joints (pencil-in-cup whittling deformity)
Sacroiliitis
Osteoporosis/ bone erosions
Treatment
GENERAL
Avoid triggers (smoking/ alcohol)
SKIN
Emollients + topical steroids (Eumovate)
Coal tar (reduce DNA synthesis)
Vit. D3 analogue (calcipotriol)
Topical retinoids
PUVA (Psoratein PO + UV-A light therapy)
UV-B light therapy
JOINTS
NSAIDs/ intra-articular steroid injections
Severe: methotrexate +/ ciclosporin
SYSTEMIC
Methotrexate (teratogenic)
Retinoids (pustular psoriasis, CI: pregnancy)
Anti-TNF (infliximab)/ ciclosporin trials
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21. Skin Ulceration: Subtypes
Venous
Increased BP in lower limb due to poor venous return
Fluid out of veins causes swelling/damage/ breakdown
Investigation: ABPI (Ankle Brachial Pressure Index), Bloods (heart/kidney disease) and radiographs
Prevention: stop smoking, improve nutrition, compression stockings
Compression bandaging, surgery
Appearance
Break in the skin
Oedema + fibrous exudate
Localised pigment loss
May encircle the lower limb
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22. Skin Ulceration: Subtypes
Arterial
Caused by ischaemia (reduced perfusion)
Surrounding skin becomes weak, damaged (slow repair)
Investigation: Bloods (clotting), arterial doppler scan/ pulse volume recording, radiographs (osteomyelitis)
Prevention: diabetic nutrition, stop smoking
Treatment: antibiotics if needed, surgery (debridement/ vascular bypass)
Appearance
Punched out appearance (intensely painful)
Gray or yellow fibrotic base
Pulses not palpable
Thin, shiny skin or absent hair growth (poor perfusion)
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23. Skin Ulceration: Subtypes
Neuropathic e.g. DM
Altered metabolism results in slow wound healing and repair
Ulcer persists and may worsen
Investigation: Blood glucose, Doppler pressure scan, swabs (infection), radiograph / X-ray (osteomyelitis)
Prevention: glycaemic control, stop smoking, comfortable shoes (lessen pressure), debridement
Appearance
Blisters and sores (chronic)
Thickening callus formation
Painless, punched out ulcers
Superadded infection (cellulitis, abscess, osteomyelitis)
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24. Skin Ulceration: Subtypes
Infective/ Traumatic
Often occurs in wound/ pre-existing ulcer
Associated with pus, exudate formation
Investigation: Swabs, Bloods (WBC), Imaging (radiograph)
Treatment: Initially broad-spectrum antibiotic, but once lab results are back – use relevant narrow-spectrum antibiotic (ANTIBIOTIC RESISTANCE) + debridement
Vasculitic
Inflammatory destruction of blood vessels leads to ischaemia and ulcer formation
Investigation: skin/ ulcer biopsy, bloods (ESR/ CRP/ WBC)
Treatment: immunosuppression (corticosteroids e.g. prednisolone/ cyclophosphamide)
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25. Skin Cancer: Squamous Cell Carcinoma
Epidermal keratinocytes
Invade dermis and metastasise
Often found on sun exposed areas (hyperkeratotic – crusty)
Risk factors
Sunlight exposure (light skin)
Radiation
Carcinogens e.g. smoking
Chronic skin disease
HPV
Longterm immunosuppression (middle aged)
Investigations
Skin biopsy (gold standard)
Fine-needle aspirate/ lymph node biopsy (metastasis ?)
Staging (CT/MRI/PET scan)
Treatment
Surgical excision
Mohs micrographic surgery
Sentinel lymph node biopsy
Local radiotherapy/ chemoherapy in metastasis
Intra-lesional interferons (topical 5 fluoracil)
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26. Skin Cancer: Squamous Cell Carcinoma
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27. Skin Cancer: Basal Cell Carcinoma
Commonest form (rodent ulcer)
Basal cells invade dermis and metastasise (slow)
Risk factors
Prolonged sun exposure (light skin)
UV radiation
Elderly
Examination
Ill-defined nodulo-ulcerative
Telangiectasia
Superficial and pigmented
Investigations
Biopsy rarely needed
Treatment
Surgical excision
Radiotherapy
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28. Skin Cancer: Basal Cell Carcinoma
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29. Skin Cancer: Melanoma
Neoplastic transformation of melanocytes (pigment forming cells)
Life threatening
A - symetry
B – order irregularity/ bleed
C – olour variation
D – iameter . 6mm
E – levation of lesion
Investigations
Excisional biopsy
Lymphoscintigraphy (drainage)
Sentinal lymph node biopsy
Staging (CT/ MRI/ PET scan)
Blood: LFT (metastasis)
Treatment
Prevention: avoid sunburn
Wide local surgical excision
Chemotherapy (cisplatin)
Biological therapy (interferon)
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30. Skin Cancer: Melanoma
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31. Infections: Cellulitis
Acute non-prurulent spreading infection of subcutaneous tissue
Overlying skin inflammation
Periorbital: swollen eyelid
Orbital: proptosis, impaired acuity and eye movement !
Often results from penetrating injury, lesions, fissuring
Strep. pyogenes
Staph. aureus (especially MRSA)
H. influenza (especially in the orbit)
Investigation
Bloods (WBC, Blood cultures)
Discharge (culture, sensitivity)
Aspiration, if prurulent
CT/MRI scan (orbital cellulitis)
Treatment
Benzylpenicillin/ tetracycline
Orbital decompression
Aspiration/ drainage of abscess
Monitor optic nerve function
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32. Infections: Cellulitis
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33. Infections: Necrotising Fasciitis
Acute infection of deeper subcutaneous tissue layers
Bacterium release toxins which destroy skin/ muscle tissue
Can be caused by
Strep. pyogenes
Staph. Aureus (MRSA)
Clostridium perfringens’
Investigations
Bloods (CRP/ WBC/ Hb/ Na+/ Creatinine/ Glucose)
Suspect if
Pain reported is greater than appearance of skin
Inflammation, fever, tachycardia, D&V
Quick discoloration to violet/ skin swelling (blister necrosis)
EMERGENCY TREATMENT
Presumptive
Broad spectrum antibiotics
Aggressive surgical debridement
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34. Infections: Necrotising Fasciitis
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35. Brief: 2° skin disorders
Skin manifestations of other disorders
HIV/AIDs (Kaposi sarcoma – red/violet/blue/black macules – nodules)
Tropical diseases (variable e.g. blisters)
Amyloidosis (deposition of hyperpigmented macules)
Breast disease
Fibroadenoma (painless, firm, solitary and mobile lump)
Cysts (smooth, easily mobile, but tender lump with variable size)
Intraductal papilloma (small, painful lump + nipple discharge)
Breast cancer (lump + puckering/ dimpling skin + inverted nipple)
Lymphoedema
Primary (filiariasis – red, itchy swelling & migrating worm seen)
Secondary (post-irradiation therapy – skin reaction or bruising)
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36. Dermatology: Phase 2 Exams
May form a large part of the marks (SAQ – Cellulitis)
Part of questions involving systemic disorders
Terminology and epidemiology is important (SBA – identifying disease)
One disease, many presentations
Usually most common diseases/ presentations
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37. Additional Revision Resources
Books
Oxford Handbook of Clinical Specialties
Rapid Medicine
Lecture Notes Dermatology
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