Dermatology Flashcards

(97 cards)

1
Q

What is basal cell carcinoma?

A

Skin neoplasm

AKA rodent ulcer

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2
Q

Summarise the epidemiology of basal cell carcinoma

A
Commonest form of skin malignancy
Common in those with fair skin
Common in areas of high sunlight exposure
Common in elderly
Rare before age of 40
Lifetime risk in Caucasians = 1 in 3
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3
Q

Explain the aetiology of basal cell carcinoma

A

Prolonged sun exposure/UV radiation

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4
Q

What are the risk factors for basal cell carcinoma?

A
Prolonged sun exposure/UV radiation
Fair skin
Gorlin's syndrome - hedgehog IC signalling cascade
Arsenic - contaminated well water
Xeroderma pigmentosum
Transplant patients
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5
Q

What are the presenting symptoms of basal cell carcinoma?

A

A chronic slowly progressive skin lesion

Usually on face, scalp, ears, trunk

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6
Q

What are the signs O/E of basal cell carcinoma?

A

Nodulo-ulcerative (most common):
Small gistening translucent skin over coloured papule, visible telangectasia, raised pearly edges

Morphoeic: yellow/white waxy plaque w ill-defined edge, more aggressive

Superficial: multiple pink/brown scaly plaques w fine edge on trunk

Pigmented:
Specks of brown/black pigment may be present in any BCC

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7
Q

How is basal cell carcinoma investigated?

A

Biopsy rarely necessary

Diagnosis mainly on clinical suspicion

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8
Q

What is erythema multiforme?

A

An acute hypersensitivity reaction of the skin and mucous membranes

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9
Q

Summarise the epidemiology of erythema multiforme

A

Any age group
Mainly in children and young adults
Twice as common in males

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10
Q

Explain the aetiology of erythema multiforme

A

Degeneration of basal epidermal cells
Development of vesicles between cells in basement membrane
Lymphocytic infiltrate around BVs and at dermo-epidermal junction

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11
Q

What are the presenting symptoms of erythema multiforme?

A

Non-specific prodromal symptoms of URTI
Sudden appearance of itching/burning/painful skin lesions
Skin lesions may fade leaving pigmentation

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12
Q

What are the signs O/E of erythema multiforme?

A

Classic target (bull’s eye) lesions w rim of erythema surrounding paler area
Vesicles/bullae
Urticarial plaques
Lesions often symmetrical and distributed over arms and legs, including palms, soles, and extensor surfaces

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13
Q

What are the risk factors for erythema multiforme?

A

Prior occurrence
Herpes simplex virus infection
Mycoplasma pneumonia

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14
Q

How is erythema multiforme investigated?

A
  1. Bloods
    FBC - abnormal WCC
    U+Es - elevated urea, nitrogen/creatinine due to volume depletion
  2. HSV serology
    +ve for HSV-1 or 2 IgM if HSV infection
  3. Rapid PCR
    +ve for varicella DNA
  4. Cold-haemagglutination serology
    +ve if M pneumoniae infection
  5. CXR:
    bronchial thickening
    interstitial infiltration
    Subsegmetnal atelectasis of lower lobe
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15
Q

What is erythema nodosum?

A

Panniculitis (inflammation of subcutaneous fat tissue) presenting as red or violet subcutaneous nodules

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16
Q

Summarise the epidemiology of erythema nodosum

A

Usually affects young adults

3x more common in females

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17
Q

Explain the aetiology of erythema nodosum

A

Delayed hypersensitivity reaction to antigens associated with various infectious agents, drugs and diseases

Commonly SARCOIDOSIS, drugs (sulphonamides, OCP, dapsone, penicillin) + streptococcal infection

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18
Q

How does erythema nodosum present?

A
Tender red/violet nodules on both shins
Sarcoidosis - uveitis, red eyes, retinal nodules, candle-wax drippings
Joint pain
Fever
Signs of underlying cause
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19
Q

How is erythema nodosum investigated?

A

Determine underlying cause

  1. FBC - raised WCC
  2. Anti-streptolysin-O titre - raised in Strep infection
  3. ESR - raised
  4. CXR - bilateral hilar adenopathy in sarcoidosis, unilateral in TB, histoplasmosis etc
  5. PPD skin testing - +ve in TB
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20
Q

What are the risk factors for erythema nodosum?

A
Streptococcal infection
Sarcoidosis
Tuberculosis
Coccidiodomycosis
Histoplasmosis
Blastmycosis
Behcet's disease
OCPs
Leprosy
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21
Q

What is a lipoma?

A

Slow-growing, benign adipose tumours that are most often found in the subcutaneous tissues

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22
Q

Summarise the epidemiology of lipomas?

A

Seen at any age
More common between 40-60 years
Relatively common

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23
Q

Explain the aetiology of lipomas

A

Benign tumours of adipocytes

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24
Q

What are the risk factors for lipomas?

A

Genetic predisposition - familial multiple lipomatosis, Gardner’s syndrome

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25
How do lipomas present?
``` Anywhere, often upper arms <5cm Lobulated Non-tender, painless Slowly enlarging Soft, compressible, mobile Do not fluctuate or transilluminate Normal overlying skin Local LN not palpable ``` Only painful on nerve compression/fat necrosis due to trauma
26
How is a lipoma investigated?
Clinical diagnosis usually | US/MRI/CT used if in doubt
27
What is molluscum contagiosum?
A common skin infection caused by a pox virus that affects children and adults
28
Summarise the epidemiology of molluscum contagiosum
Common | 90% of patients < 15 years
29
Explain the aetiology of molluscum contagiosum
Viral skin infection caused by molluscum contagiosum virus (MCV) Type of pox virus Transmission by direct skin contact
30
What are the risk factors for molluscum contagiosum?
Close contact with infected individual - towels, sex, clothes Kids Immunodeficient - HIV Swimming
31
What are the presenting symptoms of molluscum contagiosum?
Incubation period: 2-8 weeks Usually asymptomatic Tenderness, pruritus and eczema around lesion Lesions last for around 8 months
32
What are the signs O/E of molluscum contagiosum?
Firm, smooth, umbilicated papules 2-5mm in diameter Children - trunk, extremities Adults - lower abdo, genital area, inner thighs (sexual contact)
33
How is molluscum contagiosum investigated?
Clinical diagnosis | Dermatoscopy if doubt
34
What are pressure sores?
Damage to the skin, usually over a bony prominence, as a result of pressure
35
Summarise the epidemiology of pressure sores
Very common in hospitals | Most commonly occurs in elderly
36
Explain the aetiology of pressure sores
Constant pressure limits blood flow to the skin leading to tissure damage Occur as a result of pressure, friction and shear
37
What are the risk factors for pressure sores?
Immobility Alzheimer's disease Diabetes
38
What are the presenting symptoms and signs of pressure sores?
Occur over bony prominence - sacrum, heel Very tender If infected - fever, erythema, foul smell
39
How are pressure sores investigated?
No investigations necessary | Clinical diagnosis
40
What score is used to predict risk of pressure sores in patients?
Waterlow Score
41
What is psoriasis?
Chronic inflammatory skin disease, which has characteristic lesions and may be complicated by arthritis
42
Summarise the epidemiology of psoriasis
1-2% of population | Peak age of onset = 20 years
43
Explain the aetiology of psoriasis
Unknown | Genetic, environmental factors and drugs implicated
44
What are the risk factors for psoriasis?
Genes - IL23R, IL12B, TNF-a Strep throat - guttate psoriasis Flares - viral infection, immunisations Local trauma - trauma/injection/scar (Koebner phenomenon)
45
What are the presenting symptoms of psoriasis?
Itching and occasionally tender skin | Pinpoint bleeding with removing scales (Auspitz phenomenon)
46
What are the signs O/E of psoriasis?
Discoid/nummular - symmetrical, well-demarcated erythematous plaques w silvery scales over extensor surfaces (knee, elbow, scalp, sacrum) Flexural - less scaly plaques in axilla, groins, perianal and genital skin Guttate - small, drop-like lesions on trunk and limbs Palmoplantar - erythematous plaques w pustules on palms and soles Generalised pustular - pustules over limbs and torso Joint signs
47
How is psoriasis investigated?
Most patients don't need investigations Guttate - anti-streptolysin-O titre, throat swab Flexural - skin swabs to exclude candidiasis Nail clipping analysis for onychomycosis (fungal infection) Joint involvement analysed by checking for RF and radiographs
48
What is urticaria?
Itchy, red, blotchy rash resulting from swelling of the superficial part of the skin AKA hives
49
Summarise the epidemiology of urticaria
15% get at some point | Acute > chronic
50
Explain the aetiology of urticaria
Mast cell activation in the skin, resulting in histamine release Cytokine release --> capillary leakage --> skin swelling and vasodilation --> erythematous appearance
51
What are the possible triggers for urticaria?
Acute: - Allergies (foods, bites, stings) - Viral infections - Skin contact with chemicals - Physical stimuli Chronic: - Chronic spontaneous urticaria - meds, stress, infections - Autoimmune
52
What are the presenting symptoms of urticaria?
Central itchy white papule or plaque surrounded by erythematous flare Lesions vary in size and shape May be associated w swelling of soft tissues of eyelids, lips and tongue (angiooedema) Individual lesions usually transient
53
How do the timescales of acute and chronic urticaria differ?
Acute - symptoms develop quickly but normally resolve within 48h Chronic - rash persists for > 6 weeks
54
How is urticaria investigated?
Usually clinical Tests may be required for chronic - FBC, ESR/CRP, patch testing, IgE tests
55
What is eczema?
An inflammatory skin condition characterised by dry, pruritic skin with a chronic relapsing course
56
Summarise the epidemiology of eczema
All age groups Most commonly diagnosed before 5 years of age Childhood prevalence = 10-20%
57
Explain the aetiology of eczema
Genes + environment Defects in barrier function + immune dysregulation following allergen exposure Common loss-of-function variants of epidermal barrier protein FILAGGRIN = major predisposing factor --> leads to lower levels of natural moisturising factor in stratum corneum Skin also deficient in extra-cellular lipids including ceramides Breaks in epidermal barrier allow increased exposure and sensitisation to antigens
58
What are the presenting symptoms of eczema?
``` Itchy, dry skin Heat Tenderness Redness Weeping Crusting ```
59
What are the signs O/E of eczema?
``` Acute: Poorly demarcated erythematous oedematous dry scaling plaques Papules Vesicles w exudation and crusting Excoriation marks ``` ``` Chronic: Thickened epidermis Skin lichenification Fissures Change in pigmentation ```
60
Where does atopic eczema mainly affect?
Face and flexures
61
What is sebhorrheic dermatitis?
Appears where there are lots of sebaceous glands - upper back, nose and scalp Not a result of allergy (like other types of eczema) Any age Yellow greasy scales on erythematous plaques Greasy, swollen skin
62
Where is seborrhoeic dermatitis mainly affect?
``` Eyebrows Scalp Presternal area Upper back Nose ```
63
What are the risk factors for eczema?
``` Age < 5 FHx Allergic rhinitis Asthma Anthelmintic treatment in utero ```
64
What is atopic dermatitis?
Type of eczema Chronic and inflammatory Exact cause unknown - happens when immune system goes into overdrive in response to exo/endogenous allergen Usually begins in childhood (first 6 months) ``` Dry, scaly skin Erythema Itching Cracks behind ears Rash on cheeks, arms, and legs Open, crusted or weepy sores ```
65
What is contact dermatitis?
Happens when skin touches irritating substances or allergens These make skin inflamed, causing it to burn, itch and become red Usually on hands Most common irritants: solvents, industrial chemicals, detergents, fumes, tobacco smoke, paints, bleach, wool, acidic foods, astringents, alcohol in skin products Redness and rash Burning or swelling Blisters that weep or crust over
66
What is dyshidrotic eczema?
A condition that produces small, itchy blisters on edges of the fingers, toes, palms and soles of the feet Triggers = stress, allergies (hayfever), moist hands and feet, or exposure to nickel, cobalt, or chromium salts 2x in women ``` Small fluid-filled blisters (vesicles) Itching Redness Flaking Scaly, cracked skin Pain ```
67
What is discoid eczema?
AKA nummular Common type of eczema that can occur at any age ``` Symptoms = Round, coin-shaped spots Itching Dry, scaly skin Wet, open sores ``` Triggers = insect bites, reactions to skin inflammation, dry skin in winter
68
What is eczema herpeticum?
Rare but serious complication, which can happen when skin affected by eczema comes into contact with herpes virus Most often caused by contact w cold sore (HSV-1) Usually occurs on head, neck, or trunk Rash that causes blisters Malaise, swollen LNs, fever, chills, fatigue Medical EMERGENCY
69
How is eczema investigated?
Usually clinical diagnosis Contact dermatitis - skin patch allergy testing Atopic eczema - lab testing, eg elevated IgE levels Skin biopsy - exclude mycosis fungoides
70
What are epidermoid and pilar cysts?
Used to be known as sebaceous cysts But contain KERATIN, not sebum, and neither originates from sebaceous glands Epidermoid cysts originate from epidermis Pilar cysts from hair follices Cyst = closed sac with a lining (epidermis or hair root cells) + contents that are liquid or semi-solid (keratin)
71
Summarise the epidemiology of epidermoid and pilar cysts
Epidermoid - young and middle-aged adults Pilar - women more than men, middle-aged
72
Explain the aetiology of epidermoid and pilar cysts
High tesosterone and use of androgenic anabolic steroids Epidermoid - Gardner's syndrome / implantation of epidermis into dermis during trauma, surgery / blocked pore next to piercing / nevoid BCC syndrome on head and neck Pilar - inflamed hair follicle
73
What are the risk factors for epidermoid and pilar cysts?
Acne FHx - pilar (autosomal dominant) Gardner's syndrome
74
What are the presenting symptoms of epidermoid and pilar cysts?
``` Grow slowly Some become infected (red and sore) Cheesy foul-smelling pus discharge Often multiple Common in hair-bearing regions ```
75
What are the signs O/E of epidermoid and pilar cysts?
Round, smooth, tethered lump just under skin surface Overlying skin punctum May discharge granular creamy foul-smelling material ``` Pilar = scalp Epidermoid = face, neck, genital skin, upper trunk ```
76
How are epidermoid and pilar cysts investigated?
Clinical diagnosis None needed Skin biopsy/FNA to rule out differentials
77
What is squamous cell carcinoma?
Malignancy of epidermal keratinocytes of the skin
78
Summarise the epidemiology of squamous cell carcinoma
2nd most common cutaneous malignancy - 20% of all skin cancers Middle-aged and elderly Light-skinned at higher risk 2-3x more common in males
79
Explain the aetiology of squamous cell carcinoma
UV radiation | Sun exposure can lead to actinic keratosis (sun-induced precancerous lesion)
80
What are the risk factors for squamous cell carcinoma?
UV radiation Radiation Carcinogens (eg tar derivatives, cigarette smoke) Chronic skin disease (eg SLE) HPV Long-term immunosuppression Defects in DNA repair (eg xeroderma pigmentosum)
81
What are the presenting symptoms of squamous cell carcinoma?
Skin lesion Ulcerated Recurrent bleeding Non-healing
82
What are the signs O/E of squamous cell carcinoma?
Variable appearance - may be ulcerated, hyperkeratotic, crusted or scaly, non-healing Often on sun-exposed areas Palpate for local lymphadenopathy
83
How is squamous cell carcinoma investigated?
Skin biopsy - confirm malignancy and type FNA/LN biopsy - if metastasis suspected Staging - using CT, MRI, PET
84
What is herpes simplex infection?
Infection with HSV-1 or HSV-2 causing oral, genital, and ocular ulcers
85
Explain the aetiology of herpes simplex infection
HSV-1 --> herpes labialis (cold sores) But also causes 50% of initial episodes of genital herpes Also associated w HSV encephalitis HSV-2 --> genital herpes Large, enveloped dsDNA viruses Latent and lytic state Lytic infection = viral replication + transport of virus to skin, infects skin and mucosal surfaces
86
What are the presenting symptoms of herpes simplex infection?
Dysuria (in women) Tingling prodrome Genital/oral painful ulcer
87
What are the signs O/E of herpes simplex infection?
Lymphadenopathy (rare in oral) Genital ulcer - multiple, painful ulcers start as vesicular lesions --> ulceration --> crusted lesions Oral ulcer - single, recurrent, painful, self-limited ulcer along vermilion border
88
How is herpes simplex infection investigated?
Viral culture: +ve HSV PCR: +ve Type-specific serological IgG assay: +ve antibody to HSV-1 or HSV-2
89
What is melanoma?
Malignancy arising from neoplastic transformation of melanocytes, the pigment-forming skin cells
90
Summarise the epidemiology of melanoma
Leading cause of death from skin disease Steadily increasing incidence White races have 20x increased risk
91
Explain the aetiology of melanoma
DNA damage caused by UV radiation leads to neoplastic transformation 50% arise in existing naevi 50% arise in previously normal skin
92
What are the 4 histopathological types of melanoma
Superficial spreading (70%): - arises in pre-existing naevus - expands in radial fashion before vertical growth phase Nodular (15%): - arises de novo - aggressive - no radial growth phase Lentigo maligna (10%): - more common in elderly w sun damage - large flat lesions - progresses slowly - usually on face Acral lentiginous (5%): - palms, soles, subungual areas - most common type in non-white populations
93
What are the presenting symptoms of melanoma?
``` Change in size, shape, or colour of a pigmented skin lesion Redness Bleeding Crusting Ulceration ```
94
What are the signs O/E of melanoma?
``` ABCDE for examining moles: Asymmetrical Borders uneven Two or more colours Diameter > 6mm Evolving size, shape, colour ```
95
How can melanoma be investigated?
Excisional biopsy - histological diagnosis and determination of Clark's Levels and Breslow Thickness (both determine depth of penetration of melanoma) Lymphoscintigraphy - radioactive compound injected into lesion and images taken over 30m to trace lymph draining - identify sentinel nodes Sentinel LN biopsy - check for metastatic involvement Staging - US, CT, MRI, CXR Bloods - LFTs (common site of mets)
96
What are the risk factors for melanoma?
``` FHx of melanoma Personal Hx of melanoma/skin cancer Hx of atypical naevi Pale skin Red or blonde hair Sun exposure/sun bed use Immunosuppression Xeroderma pigmentosum ```
97
What are the nail signs in psoriasis?
Pitting Onycholysis Subungual hyperkeratosis