Derm Flashcards
Functions of the skin
Protect against environment Temp regulation Vit D synthesis Immunosureveillance Stop fluid loss
Which skin cells present antigens and activate t-lymphocytes?
Langerhans
Merkel cells?
Nerve endings for sensation
Melanocytes?
Produce melanin - pigment and protects nuclei from UV radiation induced DNA damage
Epidermis is made from?
Keratinocytes
Types of sweat gland and function?
Eccrine (skin)
Apocrine (axilla, anus. genitalia –> from puberty, body odour)
Stages of wound healing
Haemostasis
Inflam
Proliferation
Remodeling
What happens in haemostasis and inflammation?
Vasoconstriction and pt aggregation (clot formation)
Vasodilation, migration NP and MP –> phagocytosis of debris
What happens in proliferation and remodelling?
Granulation tissue formation and angiogenesis
Collagen fibre reorganisation, scar maturation
Why use emollients?
Rehydrate skin, re-establish surface lipid layer.
Use at dry, scaling conditions as soap substitute
SE of emollients?
Irritant - rash
Indications for topical corticosteroids?
Anti-inflammatory, anti-proliferative
Allergic/immune conditions, blistering, inflam skin, connective tissue disease, vasculitis
4 strengths of topical corticosteroid cream (weakest to strongest)
Hydrocortisone
Clobetasone butyrate (eumovate)
Betamethasone valerate (betnovate)
Clobetasol propionate (dermovate)
SEs of topical corticosteroids?
Skin atrophy, telangiectasia, striae, exacerbation skin conditions, acne
SEs of oral corticosteroids
Syndrome (Cushings) HTN Immunosuppression Psychosis Diabetes Osteoporosis Cataracts
Egs of topical abx
Fusidic acid
Mupirocin
Neomycin
SEs of abx
Local (irritation, allergy)
Systemic: GI upset, rash, anaphylaxis, candidiasis, abx assos infections
Eg of an oral retinoid
Isotretinoin, acitretin
Indications for oral retinoids?
Acne
Psoriasis
Disorders of keratinisation
SEs of oral retinoids?
Mucocutaneous reaction [dry skin, lips, eyes]
Disordered LFTs
Hypercholesterolaemia
Myalgia, arthralgia, depression
Teratogenicity
SE of ciclosporin?
HTN and renal dysfunction
MUST monitor BP, U+Es
SEs of azathioprine?
Hepatotoxicity
Myelotoxicity
Atopic eczema?
Chronic, relapsing inflammatory skin condition characterised by itchy, erytheatous scaly pathces
Where is eczema in infants?
In adults?
Infants = face + extensor
Adults = flexor surfaces
Dx of eczema?
Itchy skin + 3 of:
- history of flexural involvement
- visible flexural dermatitis
- personal hx of asthma, hayfever (or FH if <4y)
- Dry skin
- onset < 2
Ix in atopic eczema
Serum IgE
Allergy testing
Complications of eczema
Psychological stress
Bacterial superinfection
Eczema herpeticum - EMERGENCY
Mx of occupational dermatitis?
Avoid irritant (eg gloves)
Topical corticosteroids
Seborrhoeic dermatitis found where?
Scalp
Nasolabial fold
Anterior chest
What is seborrhoeic dermatitis called in babies?
Cradle cap (usually resolves by 12m)
Mx of seborrhoeic dermatitis?
Scalp?
Non-scalp?
Scalp [topical shampoo: salicylic acid, coal tar, ketoconazole. Topical corticosteroids]
Non-scalp [topical corticosteroids +/- topical ketoconazole]
If >3months –> oral ketoconazole
Psoriasis?
Inflammatory disease due to hyperproliferation of keratinocytes and inflammatory cell infiltrate
Biopsy of psoriasis?
Focal parakeratosis
Epidermal acanthosis
Associations with psoriasis?
50% - nail changes [pitting, onycholysis]
10% psoriatic arthiris
Most common form of psoriasis?
Plaque - well circumscribed, erythematous scaly plaques
Bleed on picking (Auspitz’s sign)
Guttate psoriasis appearance?
Who seen in?
Raindrop like on trunk, arms and legs
Post strep tonsillitis in the young
Mx of psoriasis?
Education, avoid triggers
Emollients
Topical corticosteroids
Vit D analogues
Phototherapy
If severe [MTX, ciclosporin, acitretin,]
Biologics [etanercept, infliximab]
Mx of guttate?
Phototherapy
Mx of pustular psoriasis?
Oral retinoid (acitretin)
Comps of acne?
Depression
Scarring
Deformity
Hyperpigmentation
Mx of mild acne?
Topical keratolytic
or topical retioid
or topical abx
Mx of mod acne?
Topical retinoid
+ oral abx (doxycycline)
Mx of severe acne?
Oral retinoid –> isotretinoin
Which cells are BCC from?
Hair follicle
RFs for SCC?
UV exposure Pre-malignant [actinic keratoses, Bowen's] Chronic inflam Immunosuppression White
Pres of SCC?
Keratotic, ill defined nodule +/- ulceration +/- bleeding
What is Bowens?
Superficial red, scaley patch on skin - easy to treat
AKA “SCC in situ”
Ix for SCC?
Biopsy
CT/MRI
Types of SCC?
Actinic keratosis
Bowen’s
Invasive - penetrates basal memb to dermis
Mets for SCC
LNs, lung, liver, brain, bone
Mx of Bowen’s disease?
Cryotherapy Topical chemo (fluoracil)
Mx of invasive SCC?
If mets?
Wide surgical excision
+ radiotherapy
BCC RFs
UV exposure Sunburn Skin type I Age Male Immunosuppresion
Pres of BCC?
Rodent ulcer
Histopathology of BCC?
Small, dark staining basal cells, invading dermis
Mx of BCC?
Surgical
How to describe a lesion?
Asymmetry Border Colour Diameter Evolution
Problem with melanoma?
Mets early
RFs melanoma?
UV exposure
Skin type I
FHx
Immunosuppressed
Where do you get melanoma?
Who?
Common on lower limbs
Young / middle aged
Appearance of melanoma?
Large + flat + irreg pigment
Growth of melanoma?
Laterally then invades deep
Ix for melanoma?
Deramatoscope
Biopsy
Assess for mets [sentinel LN biopsy, liver USS, CXR, CT chest/abdo/pelvis]
Mets from melanoma to where?
Liver
Mx melanoma in situ?
Wide local excision / Mohs
What is bullous pemphigoid?
Chronic blistering disorder usually affecting elderly
Cause of bullous pemphigoid?
Autoantibodies against hemidesmosal antigens in epidermis and dermis
Ix for bullous pemphigoid
biopsy - histopathology
Mx of bullous pemphigoid
Wound dressing, monitor for infections
Topical corticosteroids
If widespread –> Prednisolone PO + antihistamine
Immunosuppresants
What is pemphigus vulgaris?
Autoimmune blistering skin disorder affecting the middle aged
Cause of pemphigus vulgaris?
Autoantibodies against antigens in epidermis
shallower than bullous
Mx pemphigus vulgaris?
Wound dressing, monitor for infection
High dose oral steroids, immunosuppressants
Impetigo pres?
Cause?
Golden crust / vesicles
S. aureus
seen in kids
What makes susceptible to impetigo?
Trauma
Skin breaks - eg eczema
Mx impetigo
Topical fusidic acid
Intranasal mupirocin
Oral flucloxacillin
Mx of orbal cellulitis
Ceftriaxone (IV) + Vancomycin (IV) +/- orbital decompression
Risk of blindness / abscess
Causer of scalded skin syndrome?
Production of a circulating epidermolytic toxin from benzypenicillin-resistant Staph.
Mx of scalded skin
analgesia, abx (flucloxacillin), fluids
Ix of fungal infections
skin scrapings / swabs / nail clippings
Mx of fungal infections
Treat precipitating factors
Topical antifungal [ketoconazole]
Oral antifungal [itraconazole, fluconazole]
Cause of warts
HPV (6-11)
Mx of warts
Cryotherapy
Silver nitrate
Debridement
Salicylic acid
Molluscum contagiosum appearance?
Distribution?
Pearly, smooth papule with a central umbilication
Face and groin
Mx of molluscum contagiosum?
Curettage
Cryotherapy
Scabies cause?>
infection with mites
Mx of scabies?
Treat all contacts + wash clothes
Topical permethrin + antihistamine
Things to check in ulcers?
Site
Edge
Base
Cause of venous ulcers?
Chronic venous insufficicency
Signs of chronic venous insufficiency?
Ulcers
Ankle swelling, hyperpigmentation, lipodermatosclerosis, heavy legs, dry/scaly skin, telangiectasia, varicose veins, itch
Where are venous ulcers usually?
Medial/lateral malleolus
Between knee + ankle
Appearance of venous ulcers>
Large Shallow/sloping edge painless Irreg border Moist granulating base
Ix for venous ulcers?
ABPI
Swabs for microbiology
When to biopsy venous ulcers?
If atypical
or fail to heal in 12 weeks
Mx of venous ulcers?
Graduated compression + elevation
Debridement + cleaning
Dressing
Abx if cellulitis
Cause of arterial ulcers?
atherosclerosis and tissue hypoxia
When would you suspect arterial ulcer?
CV RFs, absent pulses, ischaemic features
More distal
Painful
Grey granulating base
Features of ischaemia?
Pale, pulseless, perishingly cold, parasthesia, paralysis
Dx of peripheral arterial disease?
ABPI
Systolic at ankle / systolic at arm
–> <0.9 implies disease
Mx of arterial?
DO NOT COMPRESS
Location of neuropathic ulcers?
Bottom of foot - pressure points
Mx of neuropathic ulcer?
Find cause
Diabetic foot managment (shoes, cleaning etc)
Pres of urticaria?
Itchy wheals - central swelling with peripheral erythema
Cause of urticaria?
Skin mast cells –> histamine –> permeable capillaries and venules
Mx of urticaria?
Antihistamines
What is angioedema?
Swelling of tongue,, eyelids and lips
Comps of angioedema?
Asphyxia, cardiac arrest, death
Anaphylaxis hallmarks?
Bronchospasm
Facial/laryngeal oedema
Hypotension
Mx of acute urticaria +/- angioedema with airway involved?
IM adrenaline (1/1000)
+ airway protection
+ IV chlorphenamine
+ IV hydrocortisone
Mx of chronic urticaria?
loratadine
Erythema nodosum?
Erythematous lumps on shins due to inflam of SC fat
Causes of erythema nodosum?
IBD
TB
Strep throat
Sarcoidosis
Erythema multiforme?
Hypersensitivity reaction triggered by infection –> target lesions
Cause of erythema multiforme?
mx?
Usually HSV
acute + self limiting
Cause of Stevens-Johnsons syndrome?
Medication / infection
TEN vs SJS?
Extent of skin coverage..
TEN > 30%
SJS < 10%
What characterises TEN + SJS?
Detachment of epidermis from dermis
Maculopapular rash + bullae
Keratinocye apoptosis
Sloughs at pressure
Dx of SJS / TEN?
Skin biopsy + histopathology
Mx of SJS / TEN
Help! Withdraw causative agent Dressing + topical abx / emollients IV fluids Analgesia
Necrotising fasciitis?
Cause?
Rapidly spreading infection of deep fascia with 2dary tissue necrosis
Group A haemolytic strep (pyogenes) / S aureus / Pseudomonas aeruginosa
RFs for nec fasc
abdo surg, DM, malignancy
Pres of nec fasc
SEVERE PAIN
Erythematous, blistering, necrotic skin
Systemically unwell
CREPITUS subcutaneously
Mx of nec fasc
Surgical debridement
ABCDE
Empirical broad spec –> Vanc + Taz
Rosacea pres
Flushing, dilated telangiectasia, erythema
Mx of rosacea
Topical abx/anti-inflam
+/- oral abx
Metronidazole otpical
Doxycycline PO
Seborrhoeic keratosis pres?
Multiple lesions ‘Stuck-on’, well dermacated grey-brown-black plaques on torso/head
In over 50yos
Mx of seborrhoeic keratosis
Itch –> topical steroids
Flat –> cryotherapy
Raised –> curettage/cautery
Alopecia?
AI affecting hair follicles
Mx of alopecia?
Corticteroids
+/- immunotherapy
Pemphigus vs pemphigoid?
Pemphigus goes busy –> blisters pop early
Pemphigoid is deeper so blisters more prononounced