Derm - Collated from sources such as Passmed, Zero to Finals, AMBOSS, BMJ best practice PDF

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Collated from sources such as Passmed, Zero to Finals, AMBOSS, BMJ best practice...

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Definitions:              

Flat lesions = patch, macule Raised = nodules (>5mm), papule, plaque Annular = circular rashes with a central clearing Discoid = circular Pustule = filled with pus Vesicle = filled with fluid Bigger than a vesicle = bulla Umbilicated = dimple in papule - Molloscum contagiosum or a sebaceous gland Erosion = superficial removal of skin (just epidermis) Ulcer = gone down to the dermis (deeper) Violaceous = purple e.g. pyoderma gangrenosum (“ulcer with violaceous border”) Petechiae = non-blanching red spots Purpura = bigger petechiae, non-blanching “Palpable purpura or petechiae” think vasculitis

PSORIASIS     

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~2% of population, M=F, Caucasians Relapsing, remitting disease Non-infectious, non-scarring ^ in epidermal transit time (shedding) - usually 3-4 wks, instead its 3-4 days Involves nails, skin and joints (psoriatic arthritis) o Nail changes e.g. pitting, discoloration, onycholysis, thickening o Thick scaly plaques o Arthropathy affects 1/7 pt’s ~40% have Fhx Triggers incl infection, stress, skin trauma ('Koebner phenomenon’), alcohol, smoking o Sunlight usually helps Drug causes: (can also exacerbate) o Lithium o NSAID’s o B-blockers o ACEi o Abx e.g. Tetracycline or Penicillin o Antimalarials Linked with HLA-B13, B17, Cw6 ^ risk of Metabolic syndrome, CVD, VTE and Psychological problems

Chronic plaque psoriasis  Most common  Red plaques with silvery scale  Extensor surfaces  Scalp (scalier) Guttate psoriasis  Children  Triggered by Strep infections  Raindrop lesions anywhere on the body  Pruritis can be severe Palmoplantar  Just affects these areas  Pustular

Generalised Pustular psoriasis  Emergency - admit for same day assessment  Widespread erythema  White pustules which merge to form lakes  Palms and soles Erythrodermic  Emergency - admit for same day assessment  Widespread erythema  Systemic sx  Usually after steroid withdrawal

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Investigations Clinical Dx PASI score to assess severity DLQI tool to assess impact on QOL within the last week Mx NO CURE Consider psychological impact Conservative: o Pt education - ‘” control not cure”, remove triggers, lifestyle advice Medical:  1st line = Topical therapy: Emollients + Steroid + Vit D Salicylic acid is used to remove the scales on thick plaques in order for topical therapies to work o Calcipotriol + Betamethasone OD for 4 wks initially  If there’s no improvement after 8 wks switch the Vit D analogue to BD  If there’s no improvement after 12 wks switch the corticosteroid to BD  Or consider Coal tar preparations o Tar containing preparations can be used Secondary care: Refer if  o Severe disease o Failed topical therapy o New onset guttate psoriasis o Confirm Dx 1st = Phototherapy with UVB 2-3x/wk o More suitable for pt’s with widespread disease nd 2 = Systemic therapy with Methotrexate o Retinoids, Acitretin etc are alternatives if Methotrexate fails 3rd = Biologics e.g. Adalimumab - If DLQI and PASI score >10, and all the other tx have failed. Taken as a monthly injection If there’s arthropathy = Etanercept, infliximab or methotrexate are used

ACNE     

Need to check face, back and chest Usually a FHx but no genes identified Excess androgens can cause flares e.g. PCOS, congenital adrenal hyperplasia, pregnancy Severe stress/anxiety can cause flares Some medications can cause/worsen acne: o Steroids o Lithium o AED’s o Iodides

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I. II. III. IV.

o POP (dianette is particularly bad, also high risk of PE’s) Excessive sunlight and cosmetics which block pores can exacerbate it Clinical Dx Stages: 1. Follicular epidermal hyperstimulation and plugging of the follicle 2. Excess sebum production, which can’t escape due to plugging 3. Overgrowth of Cutibacterium acnes (gram +’ve bacteria which breaks down triglycerides in the skin and releases fatty acids which trigger inflammation) 4. Inflammation causing pain, tenderness and erythema Types Just comedones (open = blackhead, closed = whitehead) Mild = comedones and a few papulopustules Moderate = Comedones, papules & pustules - more Severe = Nodulocystic acne - nodules >5mm + cysts. Causes ‘ice pick’ scarring

Aggressive forms of acne:  Conglobate acne  Acne fulminans - deep ulcerations, erosions and cysts but no comedones. More likely to have systemic effects. Can be seen in pt’s with steroids. If isotretinoin is used on mainly closed comedones acne, this can be triggered. Mx  1st line = TOPICAL ANTIMICROBIAL  Benzoyl peroxide o + Adapalene in some cases - retinoid so is CI in pregnancy, and can cause a ‘burning’ sensation as a side effect o Benzoyl peroxide can be over the counter  If this doesn’t work, try a Topical Abx + Antimicrobial o Clindamycin + Benzoyl peroxide o Benzoyl peroxide is always added in to prevent Abx resistance  Azelaic acid is used to help clear any remaining hyperpigmentation  2nd line = LYMECYCLINE or DOXYCYCLINE or ERYTHROMYCIN  + Adapalene or Benzoyl peroxide due to risk of developing resistance o Erythromycin is the only Abx approved in pregnancy o All used for a maximum of 6 months (review after 3 - think about referring to dermatology)  The COCP is an alternative  Secondary care  REFER if: o Other tx has failed o It’s affecting QOL or causing psychological distress o There’s scarring or hyperpigmentation o Or there’s diagnostic uncertainty  ISOTRETINOIN (aka Roaccutane)  80% cure rate  Fat soluble so take after a meal containing fat (can be morning or evening)  Massive teratogen o Need 2 reliable forms of contraception for 4 weeks before starting to 5 weeks after stopping o Pregnancy test at every review o No effect on male sperm  Can cause changes to lipid levels  Can worsen depression  Main SE = dry mucous membranes and flaky skin - usually needs emollients and Vaseline every 30 mins - 1hr  Photosensitivity - polymorphic light eruption  Leg/back cramps  Hepatotoxicity

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Can’t take with alcohol Makes skin more delicate - can’t wax for 6 months after taking it, delay all non-emergent surgeries and stop it if emergency surgery is needed Reduces night vision - relevant if driving at night or if they’re a pilot Interacts with Doxy/Lymecycline to cause idiopathic intracranial hypertension (both cause ICH so together there’s a combined effect)

Acne Rosacea  Recurrent facial flushing o Usually affecting nose, cheeks, forehead  Develops into persistent erythema with papules and pustules  Telangiectasia  +/- ocular rosacea (inflammation of eye/eyelid - ‘blepharitis’) o If there’s sx of Keratitis e.g. eye pain, blurred vision or photosensitivity = refer to ophthalmology  +/- rhinophyma (late complication) o Prominent rhinophyma = routine referral to plastic surgeon  May be triggered by: o Alcohol, hot drinks, caffeine, cheese, spicy food o Heat/sun exposure o CCB’s o Topical corticosteroids o Stress  Clinical Dx  If there’s persistent flushing/telangiectasia = Refer to dermatology      

Rhinophyma

Mx 1st = lifestyle changes and reviewing medications which could aggravate it e.g. CCB’s Mild-moderate  Topical Metronidazole or Azelaic acid BD for 6-9 wks Severe (extensive papules and pustules)  Oral Tetracycline or Erythromycin (can be kept up for maintenance tx) If it’s just erythema, Brimonidine 0.5% gel is used o Won’t change papules/pustules and may make telangiectasia more obvious as the redness reduces If telangiectasia is prominent, laser therapy may be used Ocular rosacea  hygiene measures, lubricants for dry eyes, oral Abx if there’s severe sx

ECZEMA Atopic Eczema  Aka atopic dermatitis  Inherited hyper-reactivity to environmental allergens  Atopy: dust mites are key trigger o Asthma o Allergic rhinitis o Eczema  Pt’s with atopic eczema have more Staph aureus colonization than normal and drier skin - ‘xerosis’  ^ risk of viral infections e.g. Eczema herpeticum - tx with PO Acyclovir for 5 days  Molluscum contagiosum - clears spontaneously in ~2 wks  Usually develops in children 20 y/o  Infants = face o DOESN’T involve the nappy area - rash here is more likely to be nappy rash or seborrheic dermatitis (e.g. cradle cap)

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o If there’s nappy rash + eczema think Zinc deficiency? (seen more in breast fed babies) Toddlers = flexures (Elbows, popliteal fossa, orbital) o ~70% of childhood eczema clears by adulthood, but relapses occur with stress Adulthood - face, elbows, hands - dry skin is predominant (‘xerosis’) Can get lichenification/hyperkeratosis or excoriations from scratching - requires Dermavate tx

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Dx ITCHY skin +3 of the following: Involvement of skin creases e.g. elbows, ankles, neck Pmhx of atopy or fhx if 5 hairs Mx Conservative: o Counselling o Wigs Medical: o 1st = Topical Corticosteroids or Minoxidil  Or intralesional corticosteroid o 2nd = PO steroids o If there’s extensive hair loss  topical immunotherapy

INFECTIONS Staph aureus  Superficial infections = Impetigo o More common in children - in infants it can px with widespread blistering o Golden yellow crust o Infectious - stay off school  Mx with Fusidic acid  Involving hair follicles (deeper) = Folliculitis, boils or carbuncle’s (when 2+ boils merge together)  Mx with PO Flucloxacillin or Erythromycin  Can cause 2o infections e.g. surgical wounds, infected Eczema  Dx = swabs Strep pyogenes / B-haemolytic Strep  Face = Erysipelas  Limbs/body = Cellulitis o Most commonly affects the leg o Identify portal of entry - heel cracks, athletes’ foot, trauma, sting/bite  check feet and in between toe webs o 1st - sudden onset malaise, fever (maybe rigors), headache o 2nd - characteristic painful, tracking erythema and swelling o Can develop recurrent attacks --> Lymphoedema  If NOT systemically unwell  outpatient PO Penicillin V  If there’s systemic sx  admit for IV Benzylpenicillin  FOR AT LEAST 1 month (in both cases) - shorter course = ^ risk of recurrence  If it’s recurrent  prophylactic Abx HPV  Warts - benign, self-limiting

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Plantar warts can coalesce to form a “mosaic plantar wart”/verruca o Resistant to tx Leave them alone Will resolve quicker with keratolytic wart paints Curettage/cryotherapy is rarely needed

HSV 

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Type 1 = above waist o Cold sores o Whitlow - painful HSV on the finger pulp seen in Dr’s, dentists etc Type 2 = below waist o Genital warts - painful  Topical Acyclovir 5x/day  Oral acyclovir 5x/day to shorten episodes

Shingles  Reactivated VZV - has been dormant in dorsal root ganglion or trigeminal nerve o If it’s along the trigeminal nerve = Ramsey Hunt syndrome  More common in elderly pt’s and more severe  Immunocompromised pt’s  Dermatomal distribution  Doesn’t cross the midline  ~3 wks to resolve  Complications = post-herpetic neuralgia (persistent pain) - need’s neurologic analgesia e.g. TCA’s  Mx = PO Acyclovir 800mg 5/day for 7 days Fungal  Dermatophytes = fungal species which invade the skin  Scaly, unilateral rash on hand/foot = fungal until proven otherwise  “Tinea” + Latin for part of body involved e.g. o Tinea capitis = headlice o Tinea corporis = body (ring worm)  Annular lesions  Scaly edge  Need to take scrapings for Dx o Tinea pedis = feet  Starts between 4th and 5 th toe, then spreads (if this area is normal, it’s unlikely to be fungal) o Tinea unguium = nail infection  Big toe most commonly  Needs to be tx as nails are a reservoir for skin infection  Skin scrapings to Dx  Mx with Topical Terbinafine 1% for 2 wks o If feet/hands affected  PO Terbinafine for 3 wks o Fingernails  6 wks o Toenails  3 months Pityriasis versicolor  Transformation of commensal yeast into an invasive infection  Caused by Malassezia furfur  On white pt’s - red/brown scaly eruption on the trunk. Once tx becomes hypopigmented. Can be more noticeable when tanned  Black pt’s - hypopigmented areas  Limited rash is mx with Ketoconazole shampoo or clotrimazole cream  More extensive = PO Ketoconazole or Itraconazole INFESTATIONS

Scabies  Sarcoptes scabiei - mite  Main entrance route (‘burrows’) = between fingers, otherwise - genitalia, nipples, elbows, feet  Very itchy everywhere o Worse at night when warm  Spread via close contact so tx all household contacts  Scratching can cause 2o Impetigo  Look at genitalia - any scabies nodules?  Mx = topical Permethrin 5% cream (for all household contacts too!) o Malathion or Benzyl benzoate are alternatives

Lice 

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Can be head, body or pubic (crabs) o Headlice is Dx by seeing lice moving in scalp - esp behind the ear o “nits” are the eggs of lice, attached to the scalp o Need to tx TWICE with a wk between tx as eggs won’t respond to initial tx o E.g. Permethrin, malathion, carbaryl shampoo Painless bites Intense itching o Can cause patches of Impetigo in the scalp Spreads by close contact so tx household contacts

DERMATOLOGICAL EMERGENCIES Erythroderma   

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‘Red man syndrome’ (men > women) Erythema affecting >90% of skin Causes: o 40% = Eczema flare o 25% = Psoriasis - often when steroid tx is withdrawn o 15% = haematological disorders e.g. lymphoma o 10% = drug related (most commonly abx - VANCOMYCIN) o Idiopathic Skin peels off 1st o Pruritis - scratching can lead to lichenification o Eventually there’s total hair loss and nail loss Sudden onset of redness and scaling, general malaise, warm skin but pt is cold/shivery due to heat loss via skin Complications:  Dehydration  Hypothermia  High-output HF - as lots of CO is diverted to the skin  Also see peripheral oedema, hypalbuminaemia o 2o infections o Pigmentary changes long term Mx Admit Keep warm! Monitor temperature, BP, pulse IV Fluids or plenty of PO fluids o Input/output chart

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Keep skin moist - wet dressings, emollients, topical corticosteroids Antihistamines for itch Tx underlying cause o E.g. stop drugs, manage infections

Vasculitis  

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Type III hypersensitivity reaction - circulating immune complexes are deposited Causes: o 50% = idiopathic o Cryoglobulinaemia o CT disease e.g. SLE or RA o Drugs o Infection o Neoplasia o Wegner’s granulomatosis o GCA o Polyarteritis nodosa Palpable purpuric rash o Can be painful o Non blanching On peripheries (usually leg) Can involve organs e.g. kidneys, lungs, intestines & joints Mx = in most cases it’s transient (lasts wks/months) so no specific tx, just mx underlying cause o If the rash is necrotic  PO steroids

Henoch Schonlein purpura  Children  After a strep infection  Px with: o Vasculitis rash o Arthritis o Abdo pain o Haematuria Erythema Nodosum   

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Raised, erythematous tender nodules (often >1cm) o May have arthralgia and fever associated Usually on legs Causes: o 20% = idiopathic o Bacterial (usually strep) o Viral o Drugs:  Sulphonamides  OCP o IBD o Sarcoidosis  Bilateral hilar lymphadenopathy  ^ACE o Behcet’s disease (rare) o Malignancy (rare) Investigations FBC, ESR

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Rule out Sarcoidosis  ACE levels, CXR

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Mx Tx underlying cause For the rash itself - rest + NSAID’s (usually Naproxen)

Erythema multiforme  Widespread maculopapular rash  Target lesions are characteristic o Spontaneously resolve but can recur o Symmetrical o Usually starts on backs of hands/feet, spreading to torso  Upper limbs > lower limbs  Usually asymptomatic  Causes: o 50% = idiopathic o Infection e.g. #1 = HSV-1  Mycoplasma (orf is a rare cause)  can follow strep or fungal infections o Can be a drug reaction  Abx  Phenytoin  NSAID’s o Lupus erythematosus o Pregnancy o Malignancy  If oral mucosa is involved = Erythema multiforme major  Clinical Dx

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Mx Supportive (spontaneously resolves) Prophylactic Abx if sx occur >5x/yr and its HSV associated

SJS 

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Like erythema multiforme major + ulceration of mucosae e.g. oral, conjunctival, genital, kidneys, liver o Refer to ophthalmology to assess eye complications e.g. corneal scarring 100x more common in HIV pt’s Causes: o Idiopathic o Drugs o Infections o Vaccinations o GVHD Systemically unwell - fever, pain, resp sx TEN is an even more severe version with a worse prognosis (mortality ~30%), affecting >10% TSA

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Mx: ABCDE Admit to ICU or Burn’s unit Fluids Nutritional support Monitor temperature as they’re unable to thermoregulate Stop causative agent Anticoagulation PPI to prevent stress related gastritis Dressings Topical antibiotic Emollients IV Ig Ciclosporin Analgesia

Angioedema/urticaria    

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Large areas of oedema involving the dermis and sub cutis Can cause SOB / acute distress Hives is a milder form px with transient pruritic wheals Causes: o Allergy e.g. food, latex o Nettle skin o Dermographism (scratches to skin which develop urticaria) o Cholinergic - brought on by exercise o Cold and heat exposure o Sunlight exposure o Idiopathic o Delayed pressure urticaria e.g. standing for a long time, carrying shopping bags o Drugs: can cause or just aggravate  Aspirin  Opiates  NSAID’s (paracetamol is usually safe) o SLE o Lymphoma o Thyrotoxicosis (women > men) o Inherited deficiency of C1 esterase inhibitor Investigations FBC, LFT, TFT, ESR ANF C1 esterase inhibitor levels if considering a familial cause Urinalysis Mx Tx underlying cause Stop any causative agents e.g. exercise, drugs Non-sedating antihistamine e.g. o Fexofenadine, Cetirizine, Desloratadine If acute, severe + respiratory distress  IM or SC Adrenaline 0.5-1mg o Repeat in 5-10 mins if needed o + IV Chlorpheniramine 10-20mg o + IV Hydrocortisone 100mg (won’t actually work for ~1hr but still given)

Bullous disorders

Pemphigoid  Elderly pt’s  1st = erythematous rash wks/months on trunk/limbs before blisters  2nd = blisters - thick walled and tense, will burst with trauma but usually will see intact blisters O/E  Deposition of IgG Ab’s in serum  Oral involvement is less likely < Pemphigus  Mx = Prednisolone 30-60mg OD + Azathioprine (to try and required dose of steroids)  Self-limiting but lasts a few months - eventually withdraw tx Pemphigus  Elderly pt’s  Thin walled flaccid blisters, usually burst so won’t see intact blisters O/E  Normal skin previously (no background erythema)  Commonly involves oral mucosa  IgG Ab’s in serum + epidermis  Mx = higher dose Prednisolone 100-300mg OD + Azathioprine Eczema herpeticum   

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Infection caused by HSV-1 usually People with atopic dermatitis are more at risk Starts on face and neck usually o Small blisters with exudate when broken (can scar) o Painful and itchy o Malaise o Fever o Chills o Lymphadenopathy Clinical Dx

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Mx PO acyclovir 400-800mg 5x/day (IV if too sick for oral) Ophthalmology assessment if there’s eye involvement

Necrotising fasciitis  

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ALL polymicrobial Different types: 1. Strep pyogenes - DM pt’s are at ^^ risk 2. GAS, Staph aureus - younger pt’s, IVDU’s. Rapid spread of infection - toxic shock syndrome can occur 3. Vibrio vulnificus - associated with aquatic injuries abroad, rapid spread Affects extremities and perineum most commonly Px with acutely unwell pt’s  high fever, tachycardia, confusion, hypotension Area becomes erythematous, hot and swollen (like cellulitis) o Can see bullae, crepitus (from gas producing organisms) and gangrene + extreme pain (out of proportion) Clinical Dx + evidence of infection 30% mortality Mx Surgical debridement (shouldn’t be delayed by investigations) o May see grey exudate and friable fascia but NO PUS + IV Abx Amputation as last resort

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