Dermatology Flashcards
**Urticaria, Angioedema, Anaphylaxis **
- Presentation
- Pathophysiology
- Investigation
- Management (doses done separately)
- When to discharge
Presentation
* Urticaria - itchy wheals
* Angioedema - tongue/lip swelling
* Anaphylaxis - bronchospasm (wheeze), facial/laryngeal oedema (stridor), hypotension, tachycardia, urticaria, angioedema
Pathophygiolosy
* Causes: Idiopathic, food, drugs, insect bites, latex. Andioedema/urtcaria can be inherited
Investigation (after stabilisation)
* Serum tryptase to confirm anaphylaxis (raised 12h post event)
* All new anaphylaxis should be referred to allergy clinic + epipen given in interim (unless drug induced)
Management
Initial Stabilisation:
* Remove trigger, lie flat (or left side if pregnant), elevate legs
* IM adrenaline (rpt after 5 mins if needed)
* Establish airway, high flow O2, monitoring, IVI bolus
* If refractory (ongoing after 2x IM adrenaline - crit care ?adrenaline infusion)
After Stabilisation:
* PO antihistamines (if persisting skin symptoms)
Discharge Home (biphasic reaction in 20%)
* Fast-track - 2h post symptom resolution - if good response to single dose, complete resolution, adequate supervision
* 6h post symptom resolution - 2 doses of IM adrenaline needed or prev biphasic reaction
* 12h - >2doses needed, pt has severe asthma, possibility of ongoing reaction (e.g. slow-release meds), late at night, difficult access to ED - observe for 12h
Adrenaline Dose for Anaphylaxis
< 6 months - 100- 150 micrograms
**6 months - 6 years ** - 150 micrograms
6-12 years - 300 micrograms
Adults - 500 micrograms (0.5ml 1 in 1,000)
Erythema Nodosum
* Presentation
* Pathohysiology
* Management
Presentation
* Discrete, tender, erythematous, nodular lesions
* Often over shins
* continue to appear for 1-2/52 then leave bruise-like discolouration
* No scarring, ulceration or atrophy
Causes
* Infection - group A B-haemolytic strep, TB, burcellosis
* Systemic - sarcoidosis, IBD, bechet’s
* Malignancy/Lymphoma
* Drugs - penicillins, sulphonamides, COCP
* Pregnancy
Management
* Supportive - bed rest, leg elevation
* NSAIDs, intralesional or PO steroids
* nodules may also resolve spontaneously
Erythema Multiforme
Presentation
Pathophysiology
Management
**Presentation **
* Target lesions. Often hands/feet then spread to torso +/- mild itch
* Major form also has mucosal involvement - normally oral membranes but can be urogenital or ocular (keratitis, conjunctival scarring, uveitis, permanent visual impairment)
Pathophysiology
* Hypersensitivity reaction.
* Triggers:
* Viral: Herpes simplex (most common)
* Bacteria: mycoplasma, streptococcus
* Drugs: penicillin, sulphonamides, carbamazepine, NSAIDs, COCP
* SLE, sarcoidosis, malignancy, idiopathic
Management
* often self-resolves BUT eye involvement needs ophthalmology
* Otherwise supportive: antihistamines, topical steroids (itch), oral washes for mild mucosal involvement (may need hosp admission if bad for support of PO intake)
Stevents Johnson Syndrome
* Presentation
* Pathophysiology
* Management
**Presentation **
-Severe systemic reaction w/ at least 2 mucosal sites involved - mucocutaneous necrosis
-Skin involvement can be limited or extensive: - maculopapular rash w/ target lesions, can develop bullae/vesices, nikolsky sign (blisters/erosions when skin is rubbed)
-Sytemic: fever, arthralgia
Pathophysiology
* mostly due to drug reactions: penicillin, sulphonamides, lamotrigine, carbamazepine, phenytoin, allopurinol, NSAIDs, COCP
Management
- Hospital admission for supportive care + to maintain haemodynamic stability
- Mortality = 5-12%
Toxic Epidermal Necrolysis
- Presentation
- Pathophysiology
- Management
**Presentation **
-Severe cutaneous drug reaction.
- Prodrmoal ‘flu-like’ illness –> rapid appearance painful erythematous rash + desquamation of skin/mucous membranes
- >30% skin involvement
**Pathophysiology **
- Severe SJS. Drug reaction.
Management
- Supportive: Isolation, fluid/electrolyte balance, nutritional support, pain management, protective dressings.
- Burns unit or ICU management
Erythroderma
- Presetation
- Pathophysiology
- Complications
- Management
**Presentation **
- Exfoliative dermatitis involving >90% of skin
- Inflamed, oedematous, scaly skin
- Itch - can be intolerable
- Systemically unwell w/ lymphadenopathy + malaise
Causes
- Prev skin disease (eg. eczema, psoriasis)
-lymphoma
-drugs (eg. sulphonamides, gold, sulphonylureas, penicillin)
-idiopathic
Complications
- Secondary infection, fluid loss, electrolyte imbalance, hypothermia, high-output HF, capillary leak syndrome
- Mortality 20-40%
Management*
- supportive
- Abx for bacterial infection
- Antihistamines may help itch
Necrotising Fascitis
- Classification
- Presentation
- Risk Factors
- Management
Classification
Rapidly spreading infection of deep fascia w/ secondary tissue necrosis
- Type 1: mixed anaerobes + aerobes (most common - often group A haemolytic strep)
- Type 2: Streptococcus pyogenes
**Presentation **
- Often presents as rapidly worsening cellulitis w/ pain out of keeping w/ physical appearance
- pain, swelling, erythema, ++tender. Late signs: skin necrosis, crepitus, gas gangrene, fever, tachycardia
Risk Factors/Causes
- Skin: recent trauma, burns, soft tissue infection
- DM (esp if on SLGT-2 inhibitors), IVDU, immunosupression, abdo surgery
Management
- Urgent referral for extensive surgical debridement
- IV abx
- mortality 20%
Eryspelas and Cellulitis
- Presentation
- Pathophysiology
- Management
Pathophysiology Both = Spreading infection of skin
- Cellulitis: deep subcutaneous tissue
- Erysipelas: acute superficial cellulitis involving dermis + upper subcutaneous tissue
Causes
- Strep pyogenes + Staph aurerus
- RF: immunosupression, wounds, leg ulcer, minor skin surgery
Presentation
- mostly lower limbs.
- Swelling, erythema, warmth, pain +/- lymphangitis
- Systemically unwell - fever, malaise, rigors (esp erysipelas)
- erysipelas- more well demarcated w/ red raised border
- Complications: local necrosis, abscess, sepsis
Management
- Abx - mild/moderate cellulitis:
- 1st line: flucloxacillin
- If pregnant: erythromycin
- Penicillin allergy: clarithromycin, erythromycin or doxyxyline
-Severe cellulitis:
- Co-amox, cefuroxime, clindamycin, ceftriaxone
- Supportive care: rest, leg elevation, dressings, analgesia
Staphylococcal Scalded Skin Syndrome
- Presentation
- Pathophysiology
- Management
Presentation
- infancy/early childhood
- Develops over hours-days. Often worse in face, neck, axillae, groins.
- Scalded skin appearance –> large flaccid bulla (intraepidermal blistering)
- ++ painful
Pathophysiology
- Due to epidermolytic toxin from benpen resistant (coagulase positive) staphylococci
Tinea
- Pathophysiology
- Classification/Presentation
- Investigation
- Management
Pathophysiology
- Superficial fungal infection (fungal infection can be dermatophyte (tinea/ringworm), yeast (candidiasis, malassezia) or mould (aspergillus))
Classification
- *Tinea Capitis *- pathes of broken hair, inflammation,scale - if untreated can cause kerion (raised, pustular, boggy mass)
- *Tinea Corporis *(ringworm) - circular lesions w/ well defined, raised, scaly edge
- Tinea pedis - athlete’s foot - moist scaling/fissuring in toewebs (can spread to sole or dorsal foot)
- *Tinea cruris *(groin/natal cleft)
- Tinea manuum (scaling/dryness in palmar creases)
- *Tinea Unguium *(yellow discolouration, thick/crumbly nail)
- Tinea incognito (due to inadequate tx of tinea - ill-defined/less scaly lesions)
Investigation
- Skin scrapings, hair or nail clippings
Management
- Risk factor management: immunosupression, moist environment
- Tinea corporis: Mild/limited can use topical antifungal cream (e.g. terbinafine or imidazole). If severe/extensive PO antifungal (terbinafine 1st line)
- Tinea capitits: needs PO antifungal + ketoconazole shampoo. PO terbinafine (for trichophyton tonsurans) + griseofulvin (for microsporum infection OR in children)
- Athlete’s foot - topical terbinafine (may then need PO)
- (topical steroids generally avoided due to risk fo tinea incognito, although can be used if marked inflam)
Pityriasis Versicolor and Pityriasis Rosea
- Presentation
- Pathophysiology
- Management
Pityriasis Rosea
- Pathophysiology
Unknown pathophys -?viral, bacterial ?non-infective
- Presentation
-Self-limiting rash, resolves in 6-10/52, often itchy
-herald patch (large circular patch on chest, abdo or back) followed by smaller scaly red oval patches - ‘christmas tree’ pattern on chest/back
-Can be preceded by mild flu-like illness (but not always)
-mostly in teens/young adults - Management
Emollient + soap substitutes
if itch: topical steroids, PO antihistamines
should self-resolve
Pityriasis Versicolor
* Pathophysiology
-Superficial fungal infection w/ melassezia
- Presentation
- hypopigmented, pink or brown patches on trunk + scale + mild pruritis
- Management
- Topical antifungal (ketokonazole shampoo)
- If failure to respond send scrapings to confirm diagnosis + give PO itraconazole
Basal Cell Carcinoma
- Presentation
- Risk factors
- Management
Presentation
- spow growing, locally invasive malignant tumour (rare to met)
- Various morphological types: Nodular (most common), superficial (plaque-like), cystic, morphoeic (sclerosing), keratotic, pigmented
- Nodular - small skin-coloured papule/nodule w/ surface telangiectasia + pearly rolled edge +/- necrotic/ulcerated centre
Risk Factors/Causes
- UV exposure, hx of frequent/severe sunburn, skin type I, ge, male, immunosupression, prev hx/genetic predisposition
Management
- surgical excision, Mohs micrographic surgery (if high risk/recurrent)
- Radiotherapy (if surgery not appropriate)
- Other: cryotherapy, curretage/cautery, topical photodynamic therapy, topical Tx e.g. imiquimod
- Would need ref if high risk e.g. eyelid, node, ears, eyes
Squamous cell carcinoma
- Presentation
- Risk factors/cause
- Management
Presentation
- Locally invasive malignant tumour. potential to met.
- Keratotic, ill-define nodule +/- ulceration
Cause/risk factors
- UV, pre malignant skin conditions (e.g. actinic keratoses/solar keratosis), chronic inflammation (e.g. leg ulcer, wound scar), immunosupression, genetics
Management
- Surgical excision
- MOHS micrographic surgery
- Radiotherapy (for large un-resectable tumours)
Malignant Melanoma
Presentation
Causes/risk factors
Types
Management
Prognosis
**Presentation **
- invasive malignant tumour of epidermal melanocytes
- 7 point weighted checklist:
- major - 2 points each
- change in size
- change in shape
- change in colour
- minor - 1 point
- diameter >7mm
- inflammation
- oozing
- change in sensation (including itch)
- 3 or more = 2ww referral
typically on legs in women + trunk in men
**Types **
- nodular - trunk, middle-aged, intermittent high-intensity UV
- Lentigo maligna melanoma - face, elderly, long term UV
- Acral lentiginous- palms/soles/nail beds - elderly -no clear relation to UV
Causes/Risk factors
- UV, skin type I, >100 moles or atypical naevus syndrome, fam hx
Investigations
- do NOT biopsy in primary care -> 2ww if susptected
- In secondary care it is staged - TNM plus AJCC scoring systeem. T is based on breslow thickness:
- Tis - in situ
- T1 - <1mm
- T2 - 1-2mm
- T3 - 2-4mm
- (T1,2,3 can be split into a (no ulceration) + b (ulceration))
- AJCC then splits into stage I - IV
**Management **
- Surgical excision - excision biopsy then wide local excision
- Radiotherapy
- Chemotherapy (if mets)
- Prognosis depends on stage + breslow thickness
What is shown by the following images?
Straberry Naevus (capillary haemangioma)
- Erythematous, raised, multilobed tumours
- Develop rapidly in 1st month of life. Increase in size till 6-9months. Then regress over years.
- Common sites: face, scalp, back (rare: upper resp tract -> obstruction)
- Management: generally nil unless problem e.g. visual field obstruction –> B-blocker (PO or topical)
Pyogenic Granuloma
- Cause: trauma, pregnancy
- intially small red/brown spot –> rapidly progress to raised red/brown/dark lesion - can bleed profusely or ulcerate
- common site: head, upper trunk, hands. Oral mucosa in pregnancy.
- Management - lesions in pregnancy resolve spontaneously post-partum. Others normally persist –> curretage, cauterisation, cryotherapy
Seborrhoeic Keratoses
- benign epidermal skin lesion
- Stuck on appearance w/ keratotic plugs
- Manage: reassurance +/- removal - curretage, cryosurgery, shave biopsy
Keratocanthoma
- Benign epithelial tumour. More in elderly.
- ‘volcano/crater’ - initially smooth + dome shaped, rapid progression to crater centrally filled w/ keratin
- Normally spontaneously regresses in 3/12 w/ scarring BUT - Management: Urgent excision (as difficult to exclude SCC)
Port-wine Stain
- Vascular birthmarks. Do NOT spontaneously resolve + can darken/become raised w/ time
- Can be associated w/ intracranial vasc abnormalities eg. Sturge Weber Syndrome
- Management: cosmetic camouflage, laser therapy
Sebaceous Cyst
- Can be: epidermoid or pilar cysts.
- location: scalp, back, ears, face, upper arm
- Features: central punctum can be present, keratinous soft, cheese-like content
- Asymptomatic doesn’t need treating but can do complete excision (recurrence common)
Erythema Ab Igne
- Reticulated, erythematous patches w/ hyperpigemented telangiectasia
- Causes: heat exposure, hypothyroidism, lymphoedema
Dermatofibroma (histiocytoma)
- benign fibrous skin lesion. Often following injury.
- Features: solitary firm papule/nodule. The overlying skin dimples on pinching the lesion.
