Pathology Flashcards
(220 cards)
1
Q
What is the visual presentation of hyperkeratosis
A
A scaly skin rash
Build up of keratin layer
2
Q
What are the 4 main reaction patterns of inflammatory skin diseases
A
Spongiotic-intraepidermal oedema e.g. eczema
Psoriasiform- elongation of the rete ridges e.g. psoriasis
Lichenoid-basal layer damage e.g. lichen planus and lupus
Vesiculobullous- blistering e.g. pemphigoid, pemphigus
3
Q
What is the characteristic of lichenoid disorders
A
Damage to basal epidermis - between epi and dermis
Most common condition is lichen planus
Can be a lichenoid drug reaction
4
Q
How does lichen planus present
A
Itchy flat topped pink/purple papules
Very ithcy
Affects wrists, forearms, shins and ankles
May get lacy, white streaks in cheeks or on papules- Wickham’s striae
5
Q
what is the main feature of immunobullous diseases
A
Blisters
vesicles and bullae
6
Q
What is pemphigus
A
Rare autoimmune bullous disease
Autoantibodies cause damage to the junctions between skin cells - intrepidermal
Loss of junction integrity causes severe blisters
7
Q
How can you treat pemphigus
A
Responds to steroids
8
Q
What is the most common subtype of pemphigus
A
Pemphigus vulgaris
80% of cases
9
Q
Describe the cause of pemphigus vulgaris
A
IgG autoantibodies made against desmoglein 3 which forms the desmosomes
Immune complexes form and complement is activated
Proteases are released and dissolve the attachments between cells - leads to acantholysis
Occurs within the epidermis itself
10
Q
what is acantholysis
A
Breakdown of intercellular adhesion sites
common to all types of pemphigus
11
Q
What causes bullous pemphigoid
A
IgG antibodies attack the hemidesmosomes that attach the basal cells to the basement membrane
This breaks down the DEJ and causes separation of dermis and epidermis
Complement is activated and the surrounding tissues are damaged
12
Q
How does bullous pemphigoid present
A
Can present with itchy red plaques and papules before the blisters develop
Subepidermal blisters - deep
Large, tense blisters on normal, red or urticarial base
When they burst, they leave erosisons but do not scar
Unlikely to affect mucosa (mouth only if at all)
typically localised to one area or widespread on trunk/ limbs
Nikolsky sign negative
13
Q
What would show up if you did immunofluorescence on a bullous pemphigoid sample
A
Linear pattern of IgG antibodies would show up along the basement membrane - solid typically green line alone BM
Would also pick up complement
14
Q
What condition is dermatitis herpetiformis associated with
A
Coeliac disease
Personal or family history
15
Q
How does dermatitis herpetiformis present
A
Extremely itchy lesions - typically preceeds blisters
Small blisters on erythematous urticarial base - often scratched off leaving crusts or excoriation
Symmetrical
Often affects the elbows, extensor forearms, knees, buttocks, face and scalp
The hallmark is papillary dermal microabscesses
16
Q
Which HLA group is dermatitis herpetiformis associated with
A
HLA-DQ2 haplotype
17
Q
What would a dermatitis herpetiformis sample look like under immunofluorescence
A
IgA deposits seen at the tips of the dermal papillae
Granular IgA deposits
18
Q
What is the aetiology of acne
A
It is a chronic inflammatory disease of the pilosebaceous units.
Increased androgens during puberty cause increased activity of sebaceous glands
Keratin and sebum plugs the pilosebaceous unit
Glands get blocked, inflamed then rupture
Infection with other bacteria (p acnes) causes further inflammation
19
Q
What is the normal distribution of acne
A
face, upper back, anterior chest
High concentration of sebaceous glands
20
Q
What is the clinical presentation of rosacea
A
Recurrent facial flushing - exacerbated by sudden change in temperature , alcohol & spicy food
Erythema
Visible blood vessels
Pustules and papules
Thickening of skin Rhinophyma - enlarged red nose
Affects nose, chin, cheeks and forehead
21
Q
How can you differentiate between acne and rosacea
A
Rosacea does not have comedones - black/white heads
Also normal sebum excretion rates
22
Q
What are some triggers of rosacea
A
Sunlight Alcohol Spicy foods Stress Sudden temperature changes
23
Q
List some topical treatments for acne
A
Bezoyl peroxide
Antibiotics
Retinoids
24
Q
How do topical retinoids work
A
Dry skin up by shrivelling the sebaceous glands and reducing secretion
Anticomedonal
25
Describe the presentation of acne vulgaris
Comedones - black/white heads
Pustules and papules
cysts
erythema
26
What is a potential complication of acne
Scarring
Can be atrophic (shallow/ice pick) or hypertrophic (keloid)
Usually after deep lesions
27
Where on the body does rosacea normally appear
Nose, chin, cheeks and forehead
28
How can you treat rosacea
```
Reduce exposure to triggers - diet, wear suncream
Topical = metronidazole, ivermectin
Oral tetracycline - long term
Roacccutane if severe
Vascular laser for telengectasia
Rhinophyma - surgery
```
29
How do you treat lichen planus
Symptomatically
Usually burns out after 12-18 months
Can use topical steroids
Oral if very severe
30
what is Nikolsky’s sign
When the top layer of skin slips away from the lower ones when rubbed slightly
Positive in pemphigus
31
Which areas of the body are typically affected by pemphigus vulgaris
```
Scalp, face, axillae, groins
Mucosal involvement (eyes, genitals) is very common
May also appear on pressure points
```
32
Which condition has higher risk, pemphigus or pemphigoid?
Pemphigus
| Very high mortality if untreated - 75-99%
33
How do you treat pemphigus
First line - oral steroids (pred)
Typically start steroid as inpatient – may be IV
Then can add another immunosuppressive agent - usually azathioprine
Topical steroids and anaesthetics are symptomatic treatment only
34
List physical causes of skin blistering
Insect bites
Burns
Friction - particularly in elderly as friable skin
35
List infectious causes of skin blistering
HSV – cold sores, eczema herpeticum
VZV – chickenpox, zoster
Coxsackie virus – hand-foot-and-mouth disease
Staph aureus – bullous impetigo, SSSS
Strep pyogenes – bullous cellulitis
36
List genetic causes of skin blistering
Epidermolysis bullosa (EB)
37
Which drug reactions can cause skin blistering
EM / Stevens-Johnson syndrome
Toxic epidermal necrolysis (TEN)
Fixed drug eruption
38
What is the role of desmosomes
Hold adjacent epidermal cells together
39
What is the role of the hemidesmosomes
Hold the epidermis to the dermis at the DEJ
40
How would you investigate suspected bullous disease
History and examination
Bloods – Usual set with inflammatory markers – ESR/CRP
May do swabs to rule out infection
Biopsy with IMF - this will be your diagnostic test
41
which age group is most affected by bullous pemphigoid
Age >60 years in majority
42
How do you treat bullous pemphigoid
Topicals: emollients, topical antisepsis / hygiene measures
First-line – topical steroid + doxycycline for localised disease
Second line – oral steroid + steroid sparing like doxy for generalised disease
May use doxy alone if disease is not severe
Rest are 3rd line onwards that isn’t responding - azithioprine, dapsone, biologics
43
Bullous pemphigoid is typically self limiting - true or false
True
However it is chronic and can take months to years to resolve without treatment
Treatment reduces recovery to 3-6 months
44
which age group is most affected by pemphigus vulgaris
Usually a disease of middle age
45
How does pemphigus vulgaris present
Flaccid vesicles/bullae
Includes oral, throat and genital lesions
They rupture easily leaving raw, denuded erosions
Nikolsky sign positive
46
How would pemphigus vulgaris present on immunofluorescence
Would see IgG deposits outlining epidermal cells
| Looks like chicken wire
47
Which age group is most affected by dermatitis herpetiformis
Mainly young adults
| Can affect all ages though!
48
How would you investigate dermatitis herpetiformis
Coeliac serology – IgA antibodies to tissue transglutaminase (tTG)
Histology of lesion- subepidermal blisters, microabscesses in dermal papillae
Biopsy uninvolved skin for detection of granular deposits of dermal papillary IgA on immunofluorescence
Small intestinal scope + biopsy
49
How do you treat dermatitis herpetiformis
Gluten-free diet - mainstay
Drugs: dapsone, Tetracyclines
50
How do you treat mild acne
Topical treatment only
e.g. Benzoyl peroxide
Topical antibiotics, retinoids
Range of anti-comedonal, inflammaotry and microbial effects
51
What are comedones
Blocked pores bascially
If closed - whitehead
If open - blackhead
52
What can cause an increase in sebum production
Androgen effect as sebaceous unit had androgen receptors
Increased androgen production - seen in puberty or androgenic hormone imbalance in females
Increased availability - decreased SHBG
Increased androgen receptor responsiveness
53
The more bacteria present in acne, the worse it is - true or false
False!
No relationship between # of bacteria and acne severity
More related to amount of sebum and ductal cornification
54
Which bacteria commonly colonise acne
Propionobacterium acnes
Staph. epidermidis
Malassezia furfur
55
How do you grade acne
Mild- scattered papules and pustules
Moderate- numerous papules, pustules and
mild atrophic scarring
Severe - as above, cysts, nodules and significant scarring
56
What factors can aggravate acne
```
Poor diet
Being pre-menstrual = common to flare
Sweating
UV
Steam or oil in environment
Stress
```
57
How do you treat moderate acne
Topical treatment and oral antibiotics or Dianette® (females)
58
How do you treat severe acne
Isotretinoin (Roaccutane®)
59
What are the side effects of benzoyl peroxide for acne
Erythema and peeling
| Bleaches clothes, hair, bedlinen and towels
60
Retinoids should be avoided in pregnancy - true or false
True
| Systemic absorption of topicals not significant but still avoid
61
What are the side effects of topical retinoids for acne
Stinging, irritation, erythema and peeling
62
Which antibiotics are used for acne
Topical:
Erythromycin
Tetracycline
Clindamycin
```
Oral:
Erythromycin
Oxytetracycline
Doxycycline
Minocycline - needs LFT monitoring
```
63
What is the main skin side effect of tetracyclines
Photosensitivity
64
If antibiotic therapy isnt working for acne should you try another
Yes
| Try a second antibiotic after 3-6 months
65
Can contraception be used to treat acne
Yes - combined pills
Typically use dianette
Oestrogen decreases androgen production
Takes 6 months to lower sebum though
Progesterone rich / Only contraceptives may exacerbate acne
66
What are the indications for starting someone on roaccutane
Nodulo-cystic acne
Inadequate response to conventional therapy
Relapse after adequate antibiotics
Significant scarring
Severe psychological impairment (dysmorphophobia)
post-inflammatory hyperpigmentation
67
How does roaccutane work
Reduces sebaceous gland activity
68
List side effects of roaccutane
```
Dry skin, lips, eyes, nose
Skin fragility
Hyperlipidaemia
Abnormal liver function
Teratogenesis- contraception
Mood alteration
Arthralgia
Acne fulminans
Hair thinning
Benign intracranial hypertension
```
69
How does tuberous sclerosis present in the skin
```
Multiple hamartomas
Angiofibromas
Peri-ungual fibromas
Shagreen patches
Ash leaf macules
```
70
What causes tuberous sclerosis
Autosomal dominant mutation
| 2/3 are de-novo
71
What causes neurofibromatosis
Autosomal dominant
| Mutation in neurofibromin gene (tumour suppressor) on chromosome 17
72
How does neurofibromatosis present in the skin
Neurofibromas
Cafe au lait macules
Axillary freckling
Lisch nodules
73
List skin manisfestations of diabetes
Infections
Leg ulcers and other complications
Some specific disease related to diabetes - Necrobiosis Lipoidica etc
74
What is erysipelas
skin infection in upper dermis - typically strep
Seen in diabetics
Confluent erythema
Well demarcated
Not raised, scaly or crusty
Would be tender, hot, painful, patient may feel unwell
75
How do you treat erysipelas
Need oral or IV antibitoics as deep
| Would probably use IV if on the face/periorbital
76
Candida is common in diabetes - true or false
True
Occurs in warm moist areas
Also seen around nails
Hyperglycaemia favours growth
77
Describe the appearance of Necrobiosis Lipoidica
Bilateral lesions - tyipcally on shins
Smooth skin surface = deeper issue
Epidermal issue will typically be dry and scaly
Erythema and yellowing seen - subcutus peeks through
78
What causes Necrobiosis Lipoidica
Technically unknown
Most patients are diabetics - ?microvascular cause
Granulomatous inflammatory reaction around destroyed collagen
79
How do you treat Necrobiosis Lipoidica
Inject steroids around lesion
| Can use tacrolimus - calcineurin inhibitor
80
How might psoriasis present in the nails
Pitting
Onycholysis (lifting of the nail plate off the nail bed)
Subungual hyperkeratosis– keratin build up below the nail
Longitudinal ridging
Thickening
Crumbling
Colour changes
81
How can you treat psoriatic nail disease
Topical steroids
Intralesional if a few nails affected
Calcipotriol
PUVA - systemic psoriasis treatment
82
How do you diagnose fungal nail disease
Take clippings
| Assess for skin involvement
83
How do you treat fungal nail disease
Topical or oral antifungals
84
How does fungal nail disease present
Thickened nails
Brittle
Yellow discoloration
85
What is a subungual haematoma
Bleeding under the nail
| Typically after obvious trauma but repeated microtrauma can be enough
86
What must be ruled out before diagnosing simple subungal haematoma
Subungual melanoma
They can bleed too
Dermoscopy can help clarify
87
How does subungal melanoma present
```
Irregular pigmentation under nail
Typically a brown/black stripe down nail
Extends to involve proximal nail fold
May bleed, ulcerate,
Abnormalities of the nail plate
```
88
How do you manage subungal melanoma
May require excision of the entire nail apparatus if not amputation
89
What is a myxoid pseudocyst
A benign, painless cyst (though lacks capsule) at the edge of the nail
Treat by draining - may recur
90
What causes lichen planus
T cell mediated autoimmune disorder
| Inflammatory cells attack an unknown protein within the skin and mucosal keratinocytes
91
How does lichen planus present in the nails
```
Thinning
Onycholysis
Pterygium(fusion of nail with nail bed)
Loss of nail
Ridges
```
92
What are Beau's lines
Transverse lines secondary to nail growth arrest, usually at a time of severe illness, chemotherapy
Deep grooved lines horizontal on nail
93
What is paronychia
Infection in the skin around a nail
Acute may be due to trauma, nail biting and usually bacterial
Chronic is typically a fungal infection
94
How do you differentiate between scarring and non-scarring alopecia
Non-scarring alopecia's demonstrate visible follicular units on dermoscopy, while scarring alopecia's are devoid of follicular units
95
What is androgenic alopecia
Typical male or female pattern baldness
| Likely due to androgen sensitivity and genetics
96
How can you manage androgenic alopecia
Monoxodil 5%(vasodilatory effects)
Males – finasteride (stops testosterone being converted to DHT)
Spironolactone
Hair transplant
Camoflage: nanogen fibres, hair piece, wig
Psychological support
97
What is telogen effluvium
Hair loss related to stressful events
Hair suddenly moves from the anagen to telogen phase causing mass hair shedding
Can be due to pregnancy, surger, illness, stress
Usually corrects itself with time
98
What causes alopecia areata
Autoimmune condition
| T-cell mediated
99
How does alopecia areata present
May have preceding tingling, ‘trichodynia’
Focal patches of confluent hair loss.
Exclamation mark hairs - thinner at base, thicker at top
100
How do you manage alopecia areata
```
Potent topical steroids
Intralesional steroids
DCP
JAK inhibiors
Camoflage
```
101
What is traction alopecia
Hair loss caused by traction
| Usually due to tight hairstyles or headgear
102
What is trichotillomania
Irresistible urge to pull at hair
| Associated with OCD, stress and anxiety - treat these to treat
103
How does trichotillomania present
Temples and vertex common sites - often on side of dominant hand
Irregularly shaped patches of hair loss
Varying lengths
104
Tinea capitis can lead to alopecia - true or false
True
| Can even scar if extensive + chronic (called kerion - highly inflamed TC lesion)
105
List 3 main causes of scarring alopecia
Discoid SLE
Lichen planopilaris
Folliculitis decalvans and Dissecting Cellulitis of the scalp
106
How does discoid lupus present on the scalp
Persistent, scaly, discoid lesions on the head and neck area
Inflammatory plaques present
Can cause scarring, discolouration
May be triggered by sunlight
107
How do you treat discoid lupus
High potency steroids
Intralesional steroids
Protopic
Systemic treatment: hydroxychloroquine, oral pred, methotrexate, other immunosuppressives
Sun protection
108
How does Lichen planopilaris present
Symptoms: itch, pain, tenderness, burning
Significant loss of hair - scarring/permanent
Common sites: forehead, nape of neck, sides of scalp
Slow to progress
Trichoscopy reveals absent follicles, white dots, tubular perifollicular scale and perifollicular erythema
109
How does folliculitis decalvans present
Follicular pustules and scarring alopecia
| Characteristically, several or many hairs can be seen coming out of a single follicle, so the scalp looks "tufted"
110
How does dissecting cellulitis of the scalp present
```
Perifollicular and follicular pustules
Nodules and pseudocysts, often with purulent exudate
Abscess
Hair loss - scarring/permanent
Keloid scars
```
111
What is hirsutism
Male pattern of secondary or post-pubertal hair growth occurring in women
May develop thicker hairs, across the moustache and beard area, lower abdomen etc
112
What can cause hirsutism
PCOS
Cushings
Congenital adrenal hyperplasia
Caused by increased androgens or stronger response to them
113
How do you manage hirsutism
COCP
Spironolactone
Metformin
Hair removal - many types
114
What is hypertrichosis
Non-hirsute excessive hair growth over and above the normal for the age, sex and race of a male or female
Can be congenital, associated with naevi or spina bifida
Aquired - malnutrition, malignancy and certain drugs
115
Which drugs can cause hypertrichosis
Ciclosporin
Phenytoin
Minoxidil - used for hair loss
116
What is DRESS
Drug exanthem with eosinophilia and systemic symptoms
Red rash skin reaction with additonal symptoms
```
Facial swelling
Lymphadenopathy
Liver involvement - check LFT
Morbilliform rash
Fever
```
May even go on to need organ transplant if multiple organ involvement
117
What is a drug exanthem
Erthematous macular + papular rash in response to medication
Usually then becomes confluent
Usually blanches
Axillae, groins hands and feet often spared.
118
How do you treat drug exanthems
Stop the offending drug
Treat symptoms - antihistamine & topical steroids, regular emollient
If DRESS give oral steroids
119
Which drugs often cause exanthem reactions
Antibitoics - penicillins, cephalasporins
Allopurinol
Anti-epileptics
NSAIDs
120
What is the main difference between SJS and TEN
SJS – mucosal involvement more likely <10% skin involved
TEN - >30% skin involved
121
Describe the presentation of SJS
Characteristic prodrome of respiratory symptoms, followed up to 14 days later by erosions of at least 2 mucosal surfaces with variable skin involvement
Pyrexia, systemic upset especially in children
May be dehydrated
Target like lesions, blisters etc
Epidermal detachment - desquamation affecting up to 10% of body
Nikolskys sign – positive, detachment of epidermis on light lateral pressure
122
How do you treat SJS and TEN
Stop any offending drug or treat underlying cause
Needs HDU or ICU as very dangerous
May have burns unit input
Supportive treatment:
Fluid management, thermoregulation, regular emollient, dressing care etc
Prevent secondary infection
123
Which drugs can cause urticaria
Can be any drug if patient is truly IgE allergic
NSAIDs and aspirin can induce a pseudourticaria
124
Describe erythema multiform
Hypersensitivity reaction to some drugs or infection
Forms target lesion on skin
Usually acute and self limiting
Can involve mucosa and lead to fever
125
List causes of erythema multiform
Idiopathic
Drugs - sulphonamides, penicillin, phenytoin
Viral infections – common with HSV in children
126
What is a fixed drug eruption
A T cell mediated reaction to a specific drug
Recurrent and fixed site when exposed to offending drug.
Erythema, oedema, bruised appearance, blistering
127
Which drugs commonly cause a fixed drug eruption
Tetracyclines
Paracetamol
Sulphonamides
NSAIDS
128
Which drugs commonly cause a phototoxic drug reaction
Quinine
Doxycycline
NSAIDS
Retinoids
129
Describe the appearance of erythema nodusum
Tender nodules usually on shins
| Deep - nodules felt on palpation, may not be visible
130
Which drugs can cause eryhtema nodusum
```
Sulfonamide
Amoxicillin
Oral contraceptive
Non-steroidal anti-inflammatory drugs
Bromide
Salicylate
```
131
Which drugs can induce bullous pemphigoid
Frusemide, penicillamine, penicillin, sulphonamides
Younger demographic compared to BP
132
How can amiodarone affect the skin
Can cause blue/black discoloration
133
How does pityriasis rosea present
Solitary lesion appears 2-4 days before onset of rash – herald patch
Truncal eruption – small pink oval lesions with peripheral “micca” scale
134
How do you treat pityriasis rosea
Self-limiting - likely viral cause
| Can use topical steroids
135
What causes vitiligo
Loss of melanocytes from affected areas
May be assoc with other autoimmune conditions
Around 30% have a family history
136
How can you treat vitiligo
Topical steroids / phototherapy may help
| Consider cosmetic camouflage
137
Which skin conditions often have a psychological component
Urticarias
Pruritis
Flushing reactions
Sweat gland disorders
Stress can also trigger flare of many skin diseases - it is an inflammatory process
138
What are salmon patches
Very common birthmark - 50% of babies
Either on face or back of neck
Thought to be due to persistant foetal circulation rather than a malformation. Tend to resolve
Neck lesions more persistant, around 10% into adulthood
139
What are haemangiomas
Vascular tumours confined to children - benign
| They occur during early childhood and most will regress and disappear
140
Describe the appearance of a port wine stain
```
Macular red birthmark
They don’t extend outwith the initial area but may thicken
These lesions persist for life
Common on the face
Typically unilateral
```
141
What causes a port wine stain
Vascular malformation of capillaries
142
When is a port wine stain associated with epilepsy
If their PWS is in the distribution of CN V1 - nose
Associated with ipsilateral vascular malformation in brain
Called Sturge Weber syndrome
143
What conditions are seen in Sturge Weber syndrome
Causes seizures, intellectual impairment, hemi-paresis and glaucoma
Will have a port wine stain in V1 distribution
144
What is Klippel-Trenauney
| syndrome
Port wine stain on limb
The associated vascular malformation involves many vessels
Leads to progressive limb overgrowth and thickening
145
Where do most infantile haemangiomas appear
Commonest on head and neck
146
Which babies are at higher risk of infantile haemangiomas
Commoner in prems & females
147
What are some of the complications of infantile haemangiomas
Can be very painful if they become ulcerated
Risk of infection
Bleeding
Compression
Obstruction of vision if around the eye or airway if near it
148
What does a tumour type lesion over the spinal cord in an infant suggest
Spina bifida
| May have an overlying haemangioma - rare
149
How would you treat a serious infantile haemangioma
Topical or Intra-lesional corticosteroids
Systemic corticosteroids
Propranolol @ 2-3 mgs /Kg for several months
Used if in a high risk area
150
What is a mongolian blue spot
Blueish birthmark
Common over buttock but can be seen anywhere
Common in black and asian skin
Can be confused with NAI - need to document when you find one
151
Congenital Melanocytic Naevi have a risk of developing into melanoma - true or false
True
Around 4 fold risk
Higher for larger lesion
152
What is a Congenital Melanocytic Naevus
A melanocytic (pigmented) mole
Aquired in childhood
May become warty or hairy
153
When would you consider an underlying cause of cafe au lait macules in a child
If they have 2 or more under the age of 2 then you would consider neuroectodermal disease
154
Which type of cell is primarily responsible for the development of urticaria, angioedema and anaphylaxis
Mast cells
| Found in the dermis
155
Histamine release from mast cells can have which cutaneous effects
Urticarial lesions or wheals due to superficial dermal oedema
Angioedema due to deep dermal or subcutaneous swelling
156
Meningococcal meningitis is associated with what type of rash
Non-blanching purpuric rash
Caused by damage of the dermal vessel walls by bacteria in the endothelial cell walls
Check with glass test
157
How do you treat suspected meningococcal disease in primary care
IV / IM Benzylpenicillin as soon as possible
| Transfer to hospital ASAP
158
How do you treat suspected meningococcal disease in secondary care
Ceftriaxone or Cefotaxime are the antibiotics of choice
159
What can cause SJS
Most commonly drugs - NSAIDs, sulphonamides, anticonvulsants and other antibiotics
Typically occurs 2-8 weeks after ingestion
May be caused by infections in some
160
How long does SJS typically last
4 - 6 weeks
161
Describe the presentation of TEN
May have initial fever, sore eyes
Rapidly spreading skin lesions, initially dusky-red macules which coalesce, leading to necrosis and detachment
Large areas of epidermal and mucosal detachment affecting >30 % body surface area
Nikolskys sign – positive, detachment of epidermis on light lateral pressure
Pain is major feature
May be resp / GI epithelial involvement
Rapidly progressing
162
What causes TEN
Almost always due to drugs
| Develops 1-3 weeks after taking the drug
163
What is erythroderma
Defined as erythema, often with scale, of at least 90% of the body surface area
Descriptor not diagnosis
164
What can cause erythroderma
```
Can be idiopathic
Dermatitis
Psoriasis
Drug reactions
Cutaneous T-cell lymphoma - may have overlying ulcerating tumours
```
Though to be due to reduced cell transit time and increased mitotic rate
165
Which drugs are common causes of erythroderma
Allopurinol
Antibiotics
Carbamazepine
PPIs
166
How do you manage erythroderma
Initial management supportive and symptomatic - fluids, temp regulation etc
Emollients +++
May need antihistamines for associated pruritus
Specific treatment for underlying condition
167
List some complications of erythroderma
Tachycardia and enter high output cardiac failure - due to increased blood flow to skin
Disturbed thermoregulation - hyperthermia
Compensatory hypermetabolism due to loss of heat
168
Describe the appearance of eczema herpeticum
Multiple, monomorphic crusted vesicles are seen
Often haemorrhagic,
May be associated bacterial infection
May also have fever, malaise, lymphadenopathy
169
What is eczema herpeticum
Widespread infection with Herpes Simplex
| Most commonly seen in children and young adults with atopic eczema
170
How do you treat eczema herpeticum
Prevention - avoid contact with friends and family with H Simplex infection
Severe cases – IV antiviral ASAP
Less severe cases – oral Rx
171
How does pustular psoriasis present
Sterile pustules on skin surface
Often surrounded by red, inflamed skin
May be localized, usually to the hands and feet
Can be widespread - this is life threatening
Usually an acute presentation
172
What can trigger pustular psoriasis
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Pregnancy
Withdrawal of corticosteroids
Infections
Hypocalcaemia
Other drugs eg salicylates, lithium
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173
List potential complications of pustular psoriasis
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Can be fatal!
Hypoalbuminaemia
Hypocalcaemia
Acute renal tubular necrosis
Liver failure
Secondary infection
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174
How do you treat pustular psoriasis
Remove any triggers if possible
Supportive treatment
Most cases require systemic therapy - Acitretin or Methotrexate
Consider PUVA
175
What is necrotising faciitis
Infection in the deep dermis, subcutaneous fat and fascia
| Group A strep is a common aetiological agent but often multiple organisms involved
176
Which factors can predispose to necrotising fasciitis
Trauma
Diabetes
Surgery
177
How does necrotising fasciitis present
painful, hot skin which is erythematous / dusky
Bullae and necrosis develops
Rapidly progressive cellulitis and necrosis
Patient is generally severely ill
178
How do you treat necrotising fasciitis
Urgent management with surgical debridement and high dose IV antibiotics is essential
179
How do you differentiate between venous and arterial ulcers
Venous – malleolus, superficial
Arterial – distal, deeper
180
How can you treat acanthosis nigricans
Can try topical retinoids / vit D analogues, sal. acid
181
What can cause acanthosis nigricans
Insulin resistance is the main cause - seen in diabetes
| Can be paraneoplastic
182
What causes pretibial myxoedema
Graves disease
| Auto-antibodies cross-react with the fibroblasts and cause thickening of the skin and fluid accumulation
183
How do you treat pretibial myoedema
Treat underlying Graves
| Correct circulation – compression stocking
184
What skin signs may be seen in hyperthyroidism
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Warm, moist smooth skin
Hyperhidrosis
Facial flushing, palmar erythema
Fine, thin hair. Diffuse alopecia
Pruritus
Pretibial myoedema seen in Graves
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185
What skin signs may be seen in hyperthyroidism
Cold, dry pale skin
Dry, coarse brittle hair, diffuse alopecia
Loss of lateral 1/3 eyebrow
Periorbital oedema and generla puffiness
Thickened brittle nails
186
What skin signs may be seen in Addison's
Increased pigmentation - due to MSH release alongside the ACTH
Seen all over but especially in palmar creases and buccal mucosa
187
Which tumours can cause increased pigmentation in the skin
Pituitary
Lung
Due to MSH release
188
Which tumours can cause hirsutism
Ovarian
Other androgenic effects like acne and baldness may be seen
189
What are the 3 types of lupus skin disease
Cutaneous / Chronic Discoid LE - only in skin
Subacute cutaneous LE
Systemic LE - typical CTD with skin signs
190
How do you treat Cutaneous / Chronic Discoid LE
Reduce sun exposure - can be a trigger
Use potent topical steroids – only condition where you start with potent in the face due to scarring risk and high inflammation
Then Hydroxycholroquine – oral
Also true for subacute type
191
How does Cutaneous / Chronic Discoid LE present
Erythematous indurated plaques on sun exposed sites
Heals with scarring
If on hairy site will lead to permanent hair loss
192
How does subacute cutaneous LE present
Usually ring-shaped erythematous scaly plaques, not indurated
Symmetrical.
Photosensitive - on sun exposed sites
Heal without scarring
193
Which conditions is more associated with the development of SLE - Cutaneous / Chronic Discoid LE or subacute cutaneous LE
Subacute
| Also more likely to be antibody positive
194
What skin signs are seen in SLE
Butterfly 'malar' rash is classic - spares nasolabial folds
Photosensitive
Nail fold capillaries prominent
May have widespread DLE type rash
195
Describe the skin changes seen in systemic sclerosis
Scleroderma
No surface change - deeper in dermis
Very hard and no give in skin – can be very restrictive
Common in fingers - sclerodactyly
Will also see telengectasia and Raynaud;s
196
List the skin features of dermatomyositis
Photosensitivity rash like that of L.E
Shawl like pattern
Heliotrope oedema of eyelids
Linear finger rash with Gottron’s papules
197
Describe the appearance of erythema multiforme
Target lesions
| Often affects knees, elbows, palms, soles and mucosal areas
198
What can cause erythema multiforme
90% due to infection – HSV
Often follows a coldsore
Some meds - sulphonamide
199
Describe the appearance of erythema nodusum
Red, tender, diffuse nodules
Will be able to feel nodules deep in skin
Typically on shins
200
What can cause erythema nodusum
Infections – Strep, TB, EB, fungal
Drugs – OCP, sulphonamides
Inflammatory bowel disease
Sarcoidosis
201
Describe the appearance of cutaneous vasculitis
Non-blanching, purpuric rash ± bullae and necrosis.
| Lower legs usually worst
202
What is livedo reticularis
Mottled cyanotic network exacerbated by cold - purple/blue lines of veins
Can be caused by hot water bottle exposure!
Also heart failure, emboli, drugs etc
203
What is Mycosis Fungoides
A cutaneous T cell lymphoma
Presents first with a reddish patch and then becomes a plaque
Can then erupt and cause erythroderma
204
Which cancers often met to the skin
Breast, lung, colon, stomach, uterus, kidney,, lung, colon
205
What is a sister mary joseph nodule
A malignant metastatic nodule found around the umbilicus
| Sign of advanced cancer
206
Which primary cancer is associated with generalised pruritis
lymphoma
207
What is pityriasis versicolor
A common yeast infection of the skin which can affect melanocyte function leading to variable pigmentation
208
What is urticaria
A transient (individual lesions last <24 hours) eruption of erythematous and oedematous swellings of the dermis, usually associated with itching
Also called hives or wheals
209
What is angioedema
Transient (24 to 48 hours at most) swellings in the deeper dermal, subcutaneous and submucosal tissues.
Often seen in lips and tongue
210
Urticaria is seen in which autoimmume disease
SLE
211
Which drug is associated with angioedema
ACE inhibitors
212
What can cause urticaria and angioedema
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Allergy
Drugs - salicylates
Physical urticarias - solar, cold, water etc.
SLE
Infections
Idiopathic - chronic type
```
213
How do you treat urticaria
Allergen avoidance if trigger identified
If no trigger then suppressive therapy
- antihistamines (H1 and H2)
- leukotrine antagonists
- serotonin antagonists
- UV phototherapy
214
How do antihistamines work
Reversible competetitive inhibitors of histamine - bind to histamine receptors
Reduces the action of histamne
215
How do you differentiate anaphylaxis from urticaria and angioedema
Will also present with respiratory compromise and hypotension - they will be shocked
216
What are the 4 main types of itch
Pruritoceptive - triggered by something in skin
Neuropathic - damage to C or P nerves
Neurogenic - no C/PNS damage but still nerves that are triggering itch
Psychogenic - psychological cause with no CNS damage
217
Which nerve fibres transmit the sensation of itch
unmyelinated C fibres
218
Which chemical mediators in the skin can trigger itch
Histamine
Tryptase
Interleukin 2
Substance P
219
What treatments are available for non-specific itch
Sedative anti-histamines
Emollients - with menthol or cooled in fridge
Antidepressants can work for neuropathic itch
Photo therapy
Opiate antagonists, serotonin (5HT3 receptor) antagonists
220
Which type of antihistamines are good for treating itch - sedative or non-sedative
Sedative
non-sedative antihistamines useless for most itch except in urticaria and insect bites
