dermatology Flashcards
What is a rash?
Rash = A change that appears on the skin, usually widespread, red, pimply.
What can infiltrate the skin?
- Inflammatory cells
- Extracellular substances

What are the main patterns of rashes?
- Epidermal = Eczematous, psoriasiform, lichenoid, vesiculobullous/ blistering
- Dermal = Vasculopathic, granulomatous, tissue deposition
What type of rash is this?

Eczematous
What type of rash it this?

Psoriasiform
What type of rash is this?

Lichenoid
What type of rash is this?

Vesiculobullous
What type of rash is this?

Vasculopathic
What type of rash is this?

Granulomatous
What is this?

Tissue deposition
What rashes are autoimmune

What is Eczema?
- Eczema = dermatitis. I tis not a disease, it is the way the skin reacts to insults: External (overwashing, scratching), or internal (skin barrier/cutaneous immune system disorder).
- All eczema has minute vesicles histiologically (spongiosis). However eczema can vary in appearance from weepy to dry
- Classification - Exogenous V Endogenous/ Acute vs chronic

Exogenous Eczema
- Contact dermatitis (irritant and allergic)
- Photosensitive
- Lichen simplex - eczema due to scratching
- Asteatotic - ‘crazy paving’
Type of eczema

Irritant contact eczema
Some examples of eczema

Prick and patch testing

COmmon drugs causing photosensitive eczema
Thiazide diuretics and quinine
WHat type of eczema

Lichen simplex
Tends to fade gradually into skin due to scratching
WHat type of eczema

- Asteatotic eczema- low fat eczema (due to drying)
Endogenous Eczema
- Atopic eczema - not fully known cause
- Discoid - mostly on limbs in older men
- Eczema due to venosu insufficiency (varicose/venous)
Type eczema

Atopic eczema
Very itchy

Gene identified associated with eczema
Philagrin - mutation in protein that allow skeratint o cross link in striatum
Type of eczema

Adult atopic eczema

Eczema herpeticum
Type eczema

Discoid
Type eczema

Varicose eczema
importance of exam vs history in dermatology
- Internal organ systems - lots of symptoms, limite dphysical signs
- Skin - many physical signs, few symptoms
- Diagnostic process - General medical (8% symptoms, 20% physical signs) and skin diagnosis (80% physical signs, 20% histroy)
Basic history of a lesion
- Same history as surgical lump
- Where
- How long been there
- Precedign abnormality
- UV exposure history: Tendency to tan/burn, fair/dark skin, freckling, sun-lover/hater, lived or worked abroad (armed services), sunbeds
Rash history
- Where did the rahs begin
- How has the rash evolved?
- Previous skin diagnoses?
- Does sun exposure worsen (lupes) or improve the rash (eczema/psoriasis)
- Symptoms: (very few) - itch, pain, weeping (almsot always eczema)
- Most PMH irrelevant - atopy (eczema?), family (psoriasis or eczema), itchy contacts (scabies)
- contact with substances - allergic contact dermatitis
- Occupation/hobies - allergic contact dermatitis
- Drugs, including when started - drug eruption
*
Examination of a rash
- Level of the pathology: Epidermis, Dermis, Subcutaenous. Touch and feel (texture-rough/smooth. thickness, elasticity)
-
Dermal - skin stays smooth, raised surface
- Macule (little flat)
- Patch (big flat)
- Papule (little area raised, dome surface)
- nodule (big raised area), dome surface
- Plaque (raised area with flat surface), usually formed by adj papules merged
- Vesicle (Filled papule, small blister)
- Bulla (Fluid filled nodule, large blister)
- Epidermal pathology - surface change - crust, scale
- Thickness of skin - Absence (erosion, ulcer, lichenificatin), thickened ( hyperkeratosis, lichenification)
- Colour change - papura/necrosis, pigmentation (haemosiderin v melanin)
- Crust – dried serum, orange/yellow, remove to reveal undelryign patho
- Scale - abrnomal stratum corneum, accumulation abnormal eratin. Hyperkeratotic
- Colour - blood leakage (purpura-non blanching, or dusky purple), viability (necrosus - green->black), pigent (pale brown -> blue/black)
- Pigmentation - haemosiderin (yellow/brown), melanin (depth pigment alters colour)
- Patterns of rash: Symmetry (external v internal causes). Some suggest diseases. Psoriasis extensor, eczema flexural, contact sensitivity, photodistribution
Describing a rash
- End of bed - comment broadly, pattern/distribution/extent, internal or external process?
- Approach patient and for each area: describe surface morphology, papules/plaques, other physical signs
- CLues from relating structures - scalp/hair/nails/mucous membranes
- Is rash epidermal or dermal
What si this

- Crust = dried serum, orange/yellow colour
- May be confused with keratin (usually white/yellow)
- Always remove crust to reveal underlying patho
- Is crust obscuring key characteristics of a tumour (means area of tumour become inviable and maybe necrotic and seep serum and this crust then builds up and can obscure patho).
Scale
- Abnormal stratum corneum
- Accumulation of abnormal keratin
- Hyperkeratotic

Thickened skin

What is this?


What is this

Ulcer

What is this

Excoriations

how colour is important in examinign a rash
- Blood leakage - purpura (non blanching), dusky purple
- Viability - necrosis - green->black
- Pigment - pale brown - blue/black

Palpable painful purpura- cutaneous vascultisi

Cutaneous vascultis progression purpura and necrosis

Necrosis
green/black necrotic tissue also seen in ulcers eg, pressure sores
Pigmentation in rashes

Essential lesions
- Epidermal (kertainocyte- derived): 4 basic tumour: Seborhheic keratosis, acitinic keratosis, basal cell carcinoma, squamous cellc arcinoma
- Melanocytic- malignant melanoma (MM)
Epidermal lesions
- Benign, basal = basal cell papilloma - seborrheic keratosis. (Seb K)
- Benign squamous = solar/actinic keratosis (AK)
- Malignant basal - basal cell carcinoma (BCC)
- Malignant squamous = squamous cell carcinoma (SCC)

What is this

Seb Ks - brown “Stuck on” plaques

What is this

Basal cell carcinoma - pale/opalescen/translucent (lacking blood)
Telangiectasia on left of original image.
Ulcerated hav little depressions.


Ulcerated basal cell carcinoma
Solar/actinic keratosis


Squamous cell carcinoma

Malignant melanoma

Malignant melanoma prognostic indicators
- Key factor - Breslow thickness
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What is a macule
Flat lesion, no elevation or depression
Change in colour

Papule
Raised so its a palpable lesion, less than 5mm in diameter

Nodule

What lesion is this

Plaque = flat topped lesion
What is this

Wheal = firm oedematous plaque/papule. Dermal oedema
What lesion is this

Vesicle - fluid colleciton smaller than 5mm
What is this

Bull - fluid collection larger than 5mm
Pustule

Pustule
What is this

Scale
What lesion is this

Crust - dried serum. Pustule, vesicle, bulla
WHat lesion is this

Erosion - partial focal loss of epidermis. Heals without scarring
What lesion is this

Ulcer
What is this?

Atrophy

What lesion is this

Lichenification
What lesion is this

Excoriations
What lesion is this?

Fissure - vertical loss of epidermis and dermis with sharply defined walls. Crack in the skin
What lesion is this

Telangiectasis- small dilated superficial blood vessels that blanch with pressure
What lesion is this?

Burrow - channel in the superficial epidermis
What lesion is this?

Target lesion
What lesion is this?

Purpura
What is this?

Alopecia
What is this

Koebnerization
What is this

How to describe a rash - SCAM
- Site
- Size and shape
- Colour
- Associated symptoms
- Margin and morphology
What skin tumour is this

Basal cell carcinoma
What skin tumoru is this

Melanoma
What is a good indicator for prognosis of skin tumours?
- MM - Breslow Thickness
- Measured from the granular layer of the epidermis to the base of the tumour.
- Reliable indicator of prognosis
Tickness + approximate 5year survval
- In situ = 95-100
- <1mm 95-100
- 1-2mm 80-96
- 2.1-4mm 60-75mm
- >4mm 50

What is this?

Squamous cell carcinoma
BCC vs SCC vs MM

The difference between eczema and psoriasis

- Eczema =
- Flexor surfaces
- ill defined, excoriated, licenified, papular.
- On the scalp - finer scale, loosely adherent, o undelrying well demarcasted plaque.
- Nail changes - associated with hand dermatitis. Chronic paronychia (thickened proximal and laterla nail fold). Surrounding skin, dry, cracked, illdefined erythema. Horizontal nail ridging.
- Psoriasis =
- Extensor surfaces
- salmon pink, well demarcasted, plaques, silvery adherence scales.
- Check, scalp and behind ears
- Nail changes - onycholysis, pitting, subingal hyperkeratosis
- Summary - FH, ask about inflammatory arthritis, check nails and scalp, back of neck, check umbilicus.

What is this?

Eczema
What is this

What is this?

Psoriasis
What are these?


Eczema nail changes
◦Nail changes associated with hand dermatitis
◦Chronic paronychia (thickened proximal and lateral nail fold)
◦Surrounding skin, dry, cracked, illdefined erythema
◦Horizontal nail ridging

What is this?

Discoid eczema
Signs of infected eczema
Take a bacterial swab

Red flag eczema - eczema herpeticum
Eczema herpeticum is a disseminated viral infection characterised by fever and clusters of itchy blisters or punched-out erosions.
Take viral swab

What is this?

Red flag for psoriasis - infected
Pustular psoriasis
Erythroderma- red flag in eczema

Erythroderma is a severe and potentially life-threatening inflammation of most of the body’s skin surface. It is also called generalized exfoliative dermatitis. It may be caused by a reaction to a medicine. Or it may be caused by another skin condition or cancer

What bacterial infection is this?

Cellulitis:
- Bacterial infection of lower dermis and subcutaneous tissue
- Red, painful, swollen skin with poorly defined edge
- Usually unilateral
- Can be associated with systemic symptoms
- Commonly caused by Strep pyogenes and Staph aureus
- Discuss risk factors e.g. previous episode of cellulitis, diabetes, venous disease etc
What bacterial infection is this?

Erysipelas:
- Affects upper dermis
- Usually caused by Group A beta haemolytic strep (Strep pyogenes)
- Affected skin has sharp raised border (cellulitis less well demarcated, and does not have such marked swelling)
- Red, firm and swollen, can be dimpled
- Treatment – penicillin antibiotic of first choice
Treatment for bacterial skin infections - cellulitis and erysipelas
- Look for portal of entry
- Swabs +/- bloods
- Analgesia, fluid, elevation
- Treat co-existing skin conditions
- Uncomplicated cellulitis can be treated with oral antibiotics
- If severe cellulitis or systemic symptoms, IV antibiotics are needed
- Antibiotics based on local protocol or sensitivities
- Prolonged course may be required
What bacterial skin infection is this?

Impetigo
- Superficial bacterial skin infection
- Pustules and honey-coloured crusted erosions
- Most often caused by S aureus , also caused by group A strep (Strep pyogenes)
- Most common in children
- Usually affecting face and hands
- Single or multiple irregular crops
- Bullous vs non-bullous - bullous due to staph exfoliative toxins
WHta bacterial skin infection is this?

Furuncle (boil)
- S aureus
- May be associated cellulitis
- 10-20% Staph carriers – nose, armpits, groin
- Topical antiseptic / compress / oral abics / be aware of sepsis
- Carbuncle = collection of interconnecting boils.
Treatment for impetigo and furuncle (bacterial skin infections)
- Antibiotic ointment eg, mupirocin or fusidic acid
- oral antibiotics
WHat type of rash is this?

- Meningococcal rash
- Neisseria meningitidis
- Spreads to blood and brain causing meningocccemia and/or meningococcal meningitis
- Petechia and purpura, may be extensive
- Dx-blood culture and LP
- Rx-Penicillins

Chancre - primary syphilis. Small firm red papule which ulcerates to form painless ulcer (chancre) Treponema pallidum

Secondary syphilis
Widespread rash and flu like symptoms
Rough, red, or reddish brown spots both on palms and soles
Wart like sores in mouth or genital area
Tertiary syphilis
Can affect multiple organ symptoms e.g neurosyphilis
Syphillis known as ‘The Great Pretender’, as can mimic many other diseases
What si this

- Lupus vulgaris (cutaneous TB)
- Mycobacterium Tuberuclosis
- Rare
- Reddish brown lesions with gelatinous consistency (apple jelly nodules)
What viral skin infection is this?

- Viral exanthem
- -Exanthem
- Widespread rash accompanied by systemic symptoms
- Common in childhood – e.g. chicken pox, measles, rubella, parvovirus b19 can present as such
- Various other viruses
- Drug reactions an important differential
What viral skin infection is this

HSV- herpes simplex virus
- Type 1 – usually orofacial
- Type 2 – usually anogenital
- After primary infection, recurrent infections can occur
- Recurrent Type 1 HSV occurs most frequently on face esp lips – herpes simplex labialis
- Dx – viral swabs for PCR
- Rx – mild cases do not required Rx, severe cases may require antivirals e.g. aciclovir
What viral skin infectin is this

Eczema herpeticum
- Dissemination viral infection
- Most cases due to HSV
- Fever, clusters of painful, itchy blisters and punched out erosions
- Commonly a complication of atopic eczema
- Complicated by secondary bacterial infection
- Antiviral treatment, IV antivirals required if patient unwell or immunocompromised
Cause of this rash?

Herpes zoster

Varicella zoster
WHat is this

- Herpes zoster opthalmicus
- Opthalmic nv ( first division of trigeminal nv)
- Ask for ophthalmology review!
What is this viral skin infection?

Viral wart aka veruca
- Caused by HPV
- Common in children and in immunocompromised
- Hard keratinous surface
- Tiny dot can be seen at centre of each scaly spot – intracorneal haemorrhage
- Common on backs of fingers and toes
- Rx-salicylic acid, cryo
broad overview of fungal skin infections
- Superficial (common) and deep (rare, tropical)
- Superficial - dermatophytes (Tinea), candida, yeasts
What is this - fungal

Tinea corporis: demonstrate how to take a skin scraping
- Dermatophyte skin infection
- Name depending of body part affected
- Prefix tinea +body site
WHat is this - fungal

Tinea pedis
What is this - fungal

Tinea capitis
What is this

Fungal infection of nails- onychomycosis
- Can be caused by dermatophytes, yeasts, moulds
- commonly due to T Rubrum
- Ix-nail clippings for microscopy and culture
- Rx- topicals antifungals if limited usually needs oral
What is this

Nail psoriasis
What is this - fungal

Candidal intertrigo
- Intertrigo describes rash in body folds
- Candida often affects intertriginous areas typically inframammary
- Pink to bright red moist patches +/- satellite papules and pustules
What is this

Pitryriasis versicolor:
- Common eyast ifnection fo the skin
- Pityriasis 0 scale appears similar to bran
- ersicolour - multiple colours
- Masselezia fungus
- Affects trunks, neck, arms
- Brown or pink patches, pale patches common in darker skin
- Asymptomatic, sometimes mildly itchy
- Microsocpy - spaghetti and meatballs appearance, yeast ad hyphae

What is this - fungal
What is this?

Seborrhoeic dermatitis
- Not infection
- Associated with proliferation of commensal Malassezia
- Its metabolites cause an inflammatory reaction
- Infantile seb derm
- Adult seb derm - scalp, face (creases around the nose, behind ears, within eyebrows) and upper trunk.
What are these

Insec tbite reaction - note the linear distribution
WHta is this infestation

- Sarcoptes scabiei
- Parasitic mite that burrows under skin
- Causes an intensely itchy rash
- Worse at night disturbing sleep
- Burrows – grey irregular tracks
- Look in webspaces of fingers and toes, palms, wrists
- Also found on elbows, nipples, buttocks, penis, soles
- Rarely involves face and scalp
- Can develop a generalised rash which is a hypersensitivity reaction few weeks after

Treatment for scabies
- 5% permethrin cream applied all over skin and left on for 8-10 hours
- Oral ivermectin 200mcg/kg
- Treatment repeated a week later to kill newly hatched mites
- Identify and treat contacts
- Launder bed linen, towels, clothing and clean rooms
- Seal items that cannot be washed in plastic bag for a week
- Itching may persist up to 6 weeks. If itching persists after 6 weeks – consider if treatment has been applied properly, if there is reinfestation or if initial diagnosis is incorrect

Pubic lice

Head lice
Emollients
- Creams:
- Pros - easy to rub in, dont rub off on clothes, will rub into weepy skin
- Cons - not the best moisturisers, contain preservativw (an cause contact allergy)
- Lotions: mainly water based
- Cons - poor moisturisers
- Pros - easy to apply to hairy areas eg, scalp
- Ointments: Greasy, form waterproof barrier
- Pros - better moisturisers than creams, better for eczema/dry skin
- Cons - dont rub in as easily as creams, can be more unwieldy, can make clothes/sheets messy
- Soap substitue emmolients.
- In eczema (impaired skin barrier) - frequent and coopious emmolient use essential for dry itchy skin
Topical steroids
- Range ptoencies
- Essential for all but mildest eczema - effective and safe with appropriate use
- Toxicity - atrophy, acne, rarely adrenal suppression
- In order potency - Betamethasone valerate (top), hydrocortisone, dermovate ointment, betnovate RD ointment).
- Many eczema patients dont use enough topical steroids due to unfoudned fears about atorphy
- S/E topical steroids = Skin thinning (atorphy) usually only with storng steroids, prolonged period, at certain sites like face and skn creases. Also acne
- Rules for steroid use - dont use storng on eif weaker steroid is effective, stronger steorids safe in short blasts and use ointment base rather than creams.

Psoriasis treatment:
- General measures - time needed to discuss condition, give patient info leaflet, advise on prepayment certificate
- Topical treatment - emollients, topical treatments
- Assess for relate docnditions - arthritis, mental health, CV disease and RFs
- Always start with emollients. Soap substitute as moisturixer. Prescribe large quantities >500g. This is to soften scale, allows scale ot life, allows acitve topical treatment to be more effective and encourage use even in quiescent periods.
- Triggers - can be stress, smoking, skin injury, infectiosn etc.
- Lifestyle advice on managin triggers.
- Trunk and limbs - calcpotriol/betamethasone
- Scalp - descale if needed with coconut oil etc then tres tongoign inflammation with topical steroids and maintainence therapy
- Flexures and genetalia - cream/ointment silikis
- Face - eumovate ointment
- Guttate psoriass (most torso and limbs).- refer for light therapy and lotion itnerim
- Palmoplantar pustular - stop smoking, dermovate ointment, moisturiser and referral hand and foot pIVA/Acitretin
- Nails - practicle tips, dovobet gel
- Psoriatic arthris - refer dermatology
Vitamin D analogues- psoriasis tx
- Calcipotriol cream- 2x daily
- Calcitriol - 2x daily
- Tacalcitol (curatoderm)
- Vit D analogue. betamethasone combo - stops keratinocytes from dividing and allows them to differentiate. Enstilar cutaneous foam
- Less messy, free fron odour, less irritant than dithranol, synergistic effect with phototherapy (dose sparing effect)
- A/E - skin irritation in around 20% with calcupotriol, avoid face and flexures with calcipotriol/dovob etc. Hypercalcaemia, avoid in inflammatory . erythrodermic psoriasis.
- Silkis - inhibits proliferation fo t lymhocytes and normalises the production of various inflammation factors.
Coal tar treatment - psoriasis
- Several creams and shampoos
- Some preps have been combined with topical steroids for synergistic effect and ease of patients use
- Epidemiological studies have not confirmed any carcinogenci potential
- MOA - not really known but thought to have anti-prolfierative effects:
- Inhibit DNA synthesis of kaeratinocytes
- Limit keratinocyte proliferation
- Slows down the abnormal cycle
- (Also anti-inflammatory effects)
- Benefits - Effective, synergistic with phototherapy, certain preps can be used on face
- A/E- odour, messty, stain clothing, can be irritant in higher doses, avoid in inflammatory/erythrodermic psoriasis.
Dithranol - psoriasis tx
- Derivative of tree bark
- SHort contact (apply, then wahs off after 20min). Dithrocream-micanol
- Over 24hours in Lassars paste (zinc and salicyclic acid)
- Wash off with oliver oil
- Respond within 20days of treatment
- Relapse rate of 10% per month.
- MOA - anti-proliferative effect on keratinocytes - inhibit DNA replciation, inhibit cellular respiration. Induce apoptosis in keratinocytes
- Outpatient or inpatient treatment. Messy, staining, smelly
- Safe and effective
- Short contact - washed off plaques after 20-30mins
- ingrams regime - combined with UVB, left on skin for 24hours.
- Pros - inexpensive, effective, synergistic with phototherapy
- A/E - irritant (burns- avoid on face and flexures), stains (fabrics and bathroom fitting irreversibly and skin reversibly), avoid in inflammatory/erythrodermic psoriasis
Topical corticosteroids - psoriasis tx
- Different strengths, often combined with coal tar or calcipotriol
- Use on limited areas, useful in flexures (trimovate), face
- Rotate topical corticosteroids with alternative non-corticosteroid preparations
- Avoid long term use as sole topical treatment- skin atrophy, tolerance
- Rebound phenomenon.
- Can transform to unstable pustular psoriasis.
Salicylates- psoraisis treatment
- Keratolytic
- useful for hyperkeratotic areas = palms, soles, scalp
- Available in: various strengths in emulsifying ointment. Also in combo with other preps (corticosteroids, coal tar, sulphur).
- Higher strengths can be irritant
Psoraiss tretment in special groups - children and pregnancy
Children:
- Calcipotriol from age 6
- DovoBet and silkis from age 12
- Coal tar - upto 6% from 1month, up to 10 from age 2
- Dithranol not recommended in infants/young children
- Salicylic acid - can be used topically from age 2
Pregnant women:
- Vit D analogues- avoid
- Low potency topical steroids
- Coal tar - intermittend use, low conc, on small percentage body and avoid 1st trimester
- Dithranol - no A/E reported
When to refer people with psoriasis
- ldiagnostic uncertainty
- lextensive disease, if unresponsive to initial therapy or difficult to self-manage
- lneed for increasing amounts or potencies of topical corticosteroids
- linvolvement of sites which are difficult to treat, e.g. face, palms and soles, genitalia, if unresponsive to initial therapy
- lneed for systemic therapy, phototherapy (e.g. guttate psoriasis), day treatment or inpatient admission
- lgeneralised erythrodermic or generalised pustular psoriasis (emergency referral is indicated); acute unstable psoriasis (urgent referral may be justified)
- lrequest for education including demonstration of topical treatment
- lfailure of appropriately used topical treatment for a reasonable time (e.g. 2–3 months)

Psoriasis consultation
- History:
- DUration
- Extensive
- Rate of relapse if chronic
- Exacerbants
- FH
- Arthrpathy
- Exam: Nails, palms, body, scalp, flexures, feet
- Explaind iagnosis
- Topical treatment - emollient, active treatment
- Explain how it is used
Treatment of this AK

Actinic keratosis:
Treatment = Liquid nitrogen cryotherapy, 5-fluorouracil cream, efudix
Treatment of this
Sunlight and the skin

UV effect on the skin

Treatment with UV radiation
