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

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

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

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

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

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

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

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

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

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

Describing Skin Lesions - 1 Nodule Macule Papule Blister

Describing Skin Lesions - 2 Pustule Wheal Cyst Plaque Scale Ulcer

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

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

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

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)

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

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)

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

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

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

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

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

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

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

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)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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