1. Dermatology - Introduction
Dr AJG McDonagh
Consultant Dermatologist
Royal Hallamshire Hospital
Sheffield

2. Structure of the skin
There are 3 layers: epidermis, dermis and subcutis
Structures within the dermis include hair follicle, sweat gland, blood & lymphatic vessels, nerves

3. Skin Structure
Epidermis – keratinocytes (produce keratin - hair, nail), melanocytes (melanin pigment), Langerhans cells (immunity)
Dermis – fibroblasts (produce connective tissue - collagen, elastin)
Subcutis – fat

4. Functions of the Skin Include
Structural – body shape & conformation
Environmental protection
Physical/ immunological
Fluid/ electrolyte balance (sweating)
Temperature control
Sensation – eg touch, heat/ cold
Sun protection & vitamin D production
Odour

5. Classification of Skin Disease
Inflammatory psoriasis, eczema, acne, lichen planus
Infections fungal, bacterial, viral, scabies
Metabolic / inherited keratin &collagen disorders, porphyria
Inherited Allergic blistering diseases, connective tissue diseases, vasculitis
Neoplasia benign eg seborrhoeic warts, moles malignant eg basal cell carcinoma, melanoma
Traumatic ulceration, erosion, burns

6. Basic topical therapeutics
creams vs ointments creams (water-based) ointments (oil-based)
emollients moisturise dry skin
corticosteroids anti-inflammatory
calcineurin inhibitors locally immunosuppressive
antibiotics, antivirals for infections, infected antifungals eczema, acne
vitamin D analogues, for psoriasis dithranol, tar

7. Basic systemic skin therapeutics
Antibiotics: acne, rosacea, infections
Antifungals/ antiviral: infections
Steroids: eczema, vascultitis, blistering/ connective tissue diseases
Azathioprine: severe eczema, blistering diseases
Methotrexate: psoriasis, eczema Ciclosporin: eczema, psoriasis
Mycophenolate: eczema, psoriasis, blistering/ connective tissue diseases
Biologics: psoriasis, pemphigus
Retioinds: acne, psoriasis

8. History Taking (1) Presenting complaint Lesion(s), rash, itch etc
Treatments
Previous Medical History
Skin conditions
Atopy (asthma, eczema, hay fever)
Medication
‘Allergies’ (type I vs type IV hypersensitivity)
General disease

9. History Taking (2) Family History Often relevant to skin problems
eg Atopic eczema, skin cancer
Occupation
eg Contact dermatitis, skin cancer
Hobbies etc
eg Contact dermatitis, steroid acne

10. Types of skin lesion Macule Papule/ nodule Pustule
Blister (vesicle/ bulla)
Plaque
Ulcer

11. Describing Skin Lesions - 1
Nodule
Macule
Papule
Blister

12. Describing Skin Lesions - 2
Pustule
Wheal
Cyst
Plaque
Scale
Ulcer

13. Curriculum for Dermatology: eleven clinical scenarios
Child with itchy skin
Urticaria
Adult/ child with acute eruption
Changing pigmented lesion
Adult with red facial eruption
Old person with facial tumour
Leg ulcer
Hair loss
Common infections
Old person with generalized pruritus
Hirsutism

14. Child with itchy skin a) Atopic eczema
Most likely to have atopic eczema
If short duration consider scabies
Treatment of eczema is firstly emollients, then topical steroids, then calcineurin inhibitors

15. 1. Child with itchy skin b) Scabies
Scabies can be difficult to detect
It is easily missed
Rash may look like eczema but less symmetrical
Need to look for burrows (scabies specific)
Treat all family members/ close contacts

16. 2. Urticaria – rapidly changing itchy rash
Red patches (erythema) & weals in the skin
Release of chemicals such as histamine from skin mast cells causes small blood vessels to leak and results in tissue swelling
Weals can be a few mm or several cm in diameter, coloured white or red
Each weal may last a few minutes or several hours
Treatment: oral antihsitamines eg loratadine (non-sedating) or chlorpheniramine (sedating)

17. 3. Adult or child with sudden rash a) Guttate psoriasis
An 18 year old male student presents with a rash on the trunk/limbs of 2 weeks’ duration
4 weeks ago he had a sore throat & was given amoxicillin for 7 days
Signs: multiple small scaly lesions on trunk
Management: topical steroid, vitamin D analogue, ultraviolet B (artificial sunlight) treatment

18. 3. Adult or child with sudden rash b) Drug eruption
Drug eruption can have many different forms
Usually due to a drug started 2 or so weeks before onset of the rash
Can be similar to rash from viral infection (exanthem)

19. 3. Adult or child with sudden rash c) Pityriasis rosea
Pityriasis rosea is usually seen in young adults
It starts with a single ‘herald’ patch on the trunk
It may be caused by a viral infection, type currently unclear

20. 3. Adult or child with sudden rash d) Viral exanthem
Viral exanthem is usually associated with systemic upset
The patient is often unwell with fever
The eruption normally clears quite quickly
Rash may be non-specific in appearance

21. 3. Adult or child with sudden rash e) plaque psoriasis
The most common presentation of psoriasis but often chronic rather than acute
Affects elbows and knees, scalp too
Use topical steroid or vitamin D analogu eg calcipotriol
If severe, need to consider ultraviolet therapy or systemic drugs, eg methotrexate, ciclosporin, biologics

22. 3. Adult or child with sudden rash f) Atopic eczema
About 50% of children with eczema have it in adult life
Often chronic
Associated with hayfever and asthma
Serum IgE level raised
Can be worsened by factors at work
Treatment as for childhood
If severe need systemic drugs - azathioprine, ciclosporin, methotrexate

23. 4. Changing pigmented lesion- a) Malignant melanoma
A 55 year old man presents with an enlarging pigmented lesion on his chest
Ask: about change in colour, size, shape, bleeding
Look for: irregular shape, colour
Management: excision & histology

24. 4. Changing pigmented lesion- b) Melanocytic naevus (mole)
Benign mole shows uniform pigmentation, regular outline
Pigmentation may increase on exposure sunlight, or in pregnancy

25. 4. Changing pigmented lesion- c) Seborrhoeic wart
Seborrhoeic warts often hyperkeratotic, may be inflamed
Have ‘stuck-on’ appearance
Frequently multiple especially on trunk
Common in the elderly

26. 5. Adult with red face- a) Adolescent with acne
Pustules, papules, erythema, blackheads
Mostly symmetrical, relatively recent onset
Embarrassment (do not forget the psychological impact of a rash)
Treatment: initially topicals, then oral antibiotic, then referral for isotretinoin (Roaccutane)

27. 5. Adult with red face- b) Adult with rosacea
Older person with pustules & erythema (no blackheads)
Rhinophyma possible (thickening of skin on nose)
Often chronic, may complain of flushing, burning or sensitive skin
Treatment: topical metronidazole, oral tetracycline

28. 5. Adult with red face- c) Seborrhoeic dermatitis
Symmetrical, cheeks, forehead (scalp)
Scaling with redness
Patient would report itching, dandruff
Often chronic
Overgrowth of yeasts occurs (pityrosporum)
Treatment: topical steroid/ anti-fungal agent

29. 6. Old person with facial tumour a) Basal cell carcinoma
Commonest human cancer
Much commoner in elderly
Commonest with fair skin, (red hair, freckles) & exposure to sunlight
Usually cured by surgical excision or radiotherapy
Very unlikely to metastasize, but can be incurable from extensive local infiltration

30. 6. Old person with facial tumour b) Squamous cell carcinoma
Squamous cell carcinoma (SCC) is common
In invasive SCC, cancer cells have grown into the dermis
Treatment: excision or radiotherapy
Prevention: sun care & treatment of premalignant lesions eg actinic keratoses

31. 7. Leg ulceration- a) Venous disease
A 60 year old woman presents with an ulcer over the left lateral malleolus
Ask: duration, previous DVT, varicose veins
Examine: site of ulcer, venous changes, pulses, Dopplers
Management: compression bandages, local dressing, treat associated eczema

32. 7. Leg ulceration- b) Arterial ulcer
Site often on foot
Absent or poor pulses, with low Doppler pressures
Compression bandaging is contra-indicated
Angiography/ angioplasty may be needed

33. 7. Leg ulceration - c) Vasculitis
Lesions purpuric at first, scattered but especially on legs
Become necrotic, than ulcerate
Investigate for internal organ disease, e.g. renal (haematuria)
Treatment: steroids, immunosuppression

34. 8. Hair loss a) Male pattern
Consider who is most likely to complain of alopecia
Classification: localised or generalised, scarring or non-scarring
Androgenetic type has strong genetic influences
Topical minoxidil or oral finasteride help

35. 8. Hair loss b) Alopecia areata
Hair loss causes psychological distress
Alopecia areata has genetic & auto-immune elements
Can treat with topical or intra-lesional steroids

36. 8. Hair loss c) Scarring alopecia
Several types of scarring of scalp can give hair loss
Examples: lupus erythematosus, lichen planus, severe infections
Treatment is to stop the disease process

37. 9. Common infections- a) Erysipelas
Unilateral eruption of sudden onset
Erythematous and swollen
Patient is unwell and pyrexial
Skin is tender, pyrexia
Infection- usually with Streptococcus
Treatment: IV antibiotics

38. 9. Common infections- b) Impetigo
Can complicate existing eruption, eg eczema, or occur de novo
Superficial infection with Staph aureus
If minor treat with topical antibiotic
If more severe, treat with systemic antibiotic, eg flucloxacillin

39. 9. Common infections- c) Herpes simplex
‘Cold sores’ present with localised blistering which can become crusted & secondarily infected
Often on face or lips
May be precipitated by sun exposure
Can affect genital area
Treatment with topical aciclovir (mild cases)
If severe give systemic antiviral

40. 10. Old person with generalised pruritus (itch)
Generalised itch is common in the elderly and often intractable
First step is a detailed history: pointers to underlying systemic disease?
Then a careful skin examination: is there scabies or subtle eczema?
If these are negative, investigate with blood tests for-
kidney disease (chronic renal failure)
liver disease (especially obstructive)
endocrine/ metabolic disease (eg diabetes mellitus, hypo/ hyperthyroidism, hypoparathyroidism
blood disease: anaemia, polycythaemia, leukaemia, lymphoma

41. 11. Hirsutism
Definition: growth of terminal hair in a male pattern in a woman
May occur due to androgen excess, or
May be constitutional, or ‘idiopathic’
Treatment: depilating creams, waxing, shaving, electrolysis, laser
Hypertrichosis is excess terminal hair growth in a non-androgen distribution