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Year 3: Sofia > Dermatology > Flashcards

Flashcards in Dermatology Deck (89)
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1
Q

What is atopic dermatitis?

A

Inflammatory skin condition characterised by dry pruritic skin which a chronic relapsing course

2
Q

What is the aetiology of atopic dermatitis?

A
  • Multifactorial aetiology, combination of genetic susceptibility and environmental factors contributing to disease development
  • Defects in skin’s barrier function and immune dysregulation following allergen exposure are thought to be key components in the development of this disease
3
Q

What is the epidemiology of atopic dermatitis?

A
  • Usually presents in childhood

- Remission is notes by 15 years of age mostly but relapse may occur later

4
Q

What are the presenting symptoms of atopic dermatitis?

A
  • Presence of risk factors: under 5yrs, FHx, allergic rhinitis, asthma, antihelminth tx in utero
  • Pruritis
  • Xerosis (dry skin)
  • Sites of skin involvement: Infants- cheeks, forehead, scalp. Children: flexures esp. wrist, ankle
5
Q

What are the signs of atopic dermatitis on examination?

A
  • Erythema
  • Scaling
  • Vesicles
  • Papules
  • Keratosis pilaris
  • Excoriations
  • Lichenification
  • Hypopigmentation
6
Q

What are the investigations for atopic dermatitis?

A
Clinical diagnosis: features of dermatitis 
Can consider:
- Allergy testing
- IgE levels: elevated
- Skin biopsy
7
Q

What is basal cell carcinoma?

A

Commonest form of skin malignancy, also known as ‘rodent ulcer’

8
Q

What is the aetiology of basal cell carcinoma?

A
  • Prolonged sun exposure or UV radiation
  • Associated with abnormalities of the patches/hedgehog intracellular signalling cascade, as seen in Gorlin’s syndrome (naevoid basal cell carcinoma syndrome).
  • Other risk factors include photosensitising pinch, tar and arseninc
9
Q

What is the epidemiology of basal cell carcinoma?

A
  • Common in those with far skin and areas of high sunlight exposure
  • Common in elderly, rare before age of 40
  • Lifetime risk in Caucasians is 1:3
10
Q

What are the presenting symptoms of basal cell carcinoma?

A

A chronic slowly progressive skin lesion usually on the face but also on the scalp, ears or trunk

11
Q

What are the signs of basal cell carcinoma on examination?

A
  • Nodulo-ulcerative (most common): Small glistening translucent skin over a coloured papule that slowly enlarges (early) or a central ulcer (‘rodent ulcer’) with raised pearly edges. Fine telangiectatic vessels often run over the tumour surface. Cystic change may be seen in larger more protuberant lesions.
  • Morphoeic: Expanding, yellow/white waxy plaque with an ill-defined edge (more aggressive)
  • Superficial: Most often on trunk, multiple pink/brown scaly plaques with a fine ‘whipchord’ edge expanding slowly; can grow to more than 10cm in diameter
  • Pigmented: Specks of brown or black pigment may be present in any type of basal cell carcinoma
12
Q

What are the investigations for basal cell carcinoma?

A

Biopsy is rarely necessary (Dx is based mainly on clinical suspicion)

13
Q

What is contact dermatitis?

A

An allergic or irritant skin reactions caused by an external agent

14
Q

What is the aetiology of contact dermatitis?

A

The top 5 allergens found to cause contact dermatitis in children were nickel sulfate, ammonium persulfate, gold sodium thiosulfate, thimerosal, and toluene-2,5-diamine

15
Q

What is the epidemiology of contact dermatitis?

A
  • Rare in first few months of life, but prevalence increases with age
  • Gender differences may be attributed to social and environmental factors; females are more likely to have nickel sensitivity because of increased wearing of jewellery, and males are more likely to have chromate sensitivity from occupational exposure.
16
Q

What are the presenting symptoms of contact dermatitis?

A
  • Risk factors: occupation with frequent exposure to water of caustic material, atopic dermatitis
  • Previous similar episodes
  • Acute onset
  • Affecting hands and face
  • Affecting sun-exposed skin
  • Sparing of non-exposed areas of skin
  • Pruritis
  • Burning
17
Q

What are the signs of contact dermatitis on examination?

A
  • Erythema
  • Vesicles and bullae
  • Lichenoid lesions
  • Corrosion or ulceration
  • Scaling
18
Q

What are the investigations for contact dermatitis?

A
  • Patch testing: positive result show inflammation graded on a 1+ to 3+ scale within 2-7 days of application
  • Repeated open application test pr provocative use test: Inflammation or dermatitis at application site
19
Q

What is eczema?

A

A pruritic papulovesicular skin reaction to endogenous or exogenous agents

20
Q

What is the aetiology of Eczema?

A

Numerous varieties caused by a diversity of triggers

  • Exogenous: Irritant, contact, phototoxic
  • Endogenous: Atopic, seborrhoeic, pompholyx, varicose, lichen simplez
  • Irritant: Prolonged skin contact with a cell-damaging irritant
  • Contact: Type IV delayed hypersensitivity to allergen
  • Atopic
  • Seborrhoeic: Pityrosporum yeast
  • Varicose: Increased venous pressure in lower limbs
21
Q

What is the epidemiology of eczema?

A
  • Prevalence: 4%

- Atopic: Onset is commonly in first year of life

22
Q

What are the presenting symptoms of eczema?

A
  • Itching (can be severe)
  • Heat, tenderness, redness weeping, crusting
  • Enquire into occupational exposures or irritants used at home (e.g. bleach)
  • Enquire into family/personal history of atopy (e.g. asthma, hay fever, rhinitis)
23
Q

What are the signs of acute eczema on examination?

A
  • Poorly demarcated erythematous oedematous dry scaling patches
  • Papules, vesicles with exudation and crusting, excoriation marks
24
Q

What are the signs of chronic eczema on examination?

A
  • Thickened epidemis
  • Skin lichenification
  • Fissures
  • Changes in pigmentation
25
Q

What are the signs of different types of eczema on examination?

A
  • Contact & irritant: Eczema reaction occurs where irritant/allergent comes into contact with skin
  • Atopic: Particularly affects face and flexures
  • Seborrhoeic: Yellow greasy scales on erythematous plaques, particular in the nasolabial folds, eyebrows, scalp and presternal area
  • Pompholyx: Acute and often recurrent vesicobullous eruption on palms and soles
  • Varicose: Eczema of lower legs, associated with marked varicose veins
  • Nummular: Coin shaped on legs and trunk
  • Asteototic: Dry, ‘crazy’ pairing’ pattern
26
Q

What are the investigations for contact eczema?

A

Skin patch testing: Disc containing postulated allergen in diluted and applied to back for 48h
- Positive if allergen induces a red raised lesion

27
Q

What are the investigations for atopic eczema?

A

Swab for infected lesions (bacteria, fungi, viruses)

28
Q

What is erythema multiforme?

A

An acute hypersensitivity reaction of the skin and mucous membranes
- Stevens-Johnson syndrome is a severe form with bullous lesions and necrotic ulcers

29
Q

What is the aetiology of erythema multiforme?

A
  • Drugs: Sulfonamides, penicillin, phenytoin, barbiturates
  • Infection: Viral (HSV, EBV, coxsackie, adenovirus, ORF), Bacterial (M. pneumoniae, Chlamydiae), Fungal (Histoplasmosis)
  • Inflammatory: Rheumatoid arthritis, SLE, sarcoidosis, UC, systemic vasculitis
  • Malignancy: Lymphomas, leukaemia, myeloma
  • Radiotherapy
30
Q

What is the epidemiology of erythema multiforme?

A
  • Non specific prodromal symptoms of upper respiratory tract infection
  • Sudden appearance of itching/burning/painful skin lesions, may may fade, leaving behind pigmentation
31
Q

What are the signs of erythema multiforme on examination?

A
  • Classing target (bulls eye) lesions with a rim of erythema surrounding a paler area, vesicles/bullae, urticarial plaques
  • Lesions are often symmetrical, distributed over the arms and legs including the palms, soles and the extensor surfaces
32
Q

What are the investigations for erythema multiforme?

A

Usually unnecessary as is a clinical diagnoses. But can identify precipitating factor

  • Blood: Raised WCC, eosinophils, ESR, CRP, throat swab, serology, albumin
  • Imaging: CXR: Exclude sarcoidosis and atypical pneumonias
  • Skin biopsy
33
Q

What is erythema nodosum?

A

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

34
Q

What is the aetiology of erythema nodosum?

A

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

  • Infection: Bacterial (Strep, TB, Yersinia, Chlamidya), viral (EBV), fungal (histoplasmosis), protozoal (toxoplasmosis)
  • Systemic disease: Sarcoidosis, IBD, Behcet’s disease
  • Malignancy: Leukaemia, Hodgkin’s disease
  • Drugs: Sulphonamides, penicillin, Oral contraceptive pill
  • Pregnancy
35
Q

What is the epidemiology of erythema nodosum?

A

Usually affects young adults

Female: Male: 3:1

36
Q

What are the presenting symptoms of erythema nodosum?

A
  • Tender red or violet nodules develop bilaterally on the shins and occasionally on the thighs and forearms
  • Fatigue, fever, anorexia, weight loss and arthralgia are often also present
  • Symptoms of the underlying aetiology
37
Q

What are the signs of erythema nodosum on examination?

A
  • Crops of red or violet-dome shaped nodules usually present on both shins (occasionally involving thighs or forearms), which are tender to palpation
  • Low-grade pyrexia. Joints may be tender and painful on movement
  • Signs of the underlying aetiology
38
Q

What are the investigations for erythema nodosum?

A

To determine underlying aetiology

  • Blood: Anti-streptolysin-O titre at diagnosis and 2-4 weeks later to assess for antecedent strep infection. FBC, U&E, CRP, ESR, LFT
  • Throat swab and culture
  • Mantoux/Heaf skin testing: for TB
  • CXR: Look for hilar adenopathy or other evidence of pulmonary sarcoidosis
39
Q

What are lipomas?

A

Slow growing benign tumours of adipose tissue

- Lipomatosis: Multiple contagious lipomas that cause distortion of SC tissues

40
Q

What is the aetiology of lipomas?

A
  • Unknown

- A rare presentation is multiple tender lipomas (Dercum’s disease)

41
Q

What is the epidemiology of lipomas?

A
  • All ages
  • Mostly 40-60
  • Rare in children
  • No gender preference
42
Q

What are the presenting symptoms of lipomas?

A
  • Pt notices lump, usually painless and slowly enlarging, unless subject to trauma when fat necrosis may cause it to swell and become tender
43
Q

What are the signs of lipomas on examination?

A
  • Can occur anywhere there are adipose tissue reserves, common in the SC tissue of the upper arms
  • Nontender, soft, compressible, but do not usually fluctuate or transilluminate except if large
  • Do not have fluid thrill and are dull to percussion
  • Overlying skin usually normal
  • Variable size, usually ovoid or spherical, often lobulated
  • Local lymph nodes should not be palpable
44
Q

What are the investigations for lipomas?

A
  • Usually none necessary

- MRI can be used visualising deeply sited lipomas

45
Q

What is melanoma?

A

Malignancy arising from neoplastic transformation of melanocytes, the pigment forming cells of the skin. Leading cause of death from skin disease.

46
Q

What is the aetiology of melanoma?

A
  • DNA damage in melanocytes caused by UV radiation results in neoplastic transformation
  • 50% arise in pre-existing naevi, 50% in previously normal skin.
47
Q

What are the histological types of melanoma?

A

1) Superficial spreading: typically arises in pre-existing naevus, expands in radial fashion before vertical growth phase
2) Nodular: Arises de novo, aggressive, no radial growth phase
3) Lentigo maligna: More common in elderly with sun damage, large flat lesions, follow an indolent growth course. Usually on the face
4) Acral lentiginous: Arise on palms, soles and sublungual areas. Most common type in non-white populations

48
Q

What is the epidemiology of melanoma?

A
  • Steadily increasing incidence

- White races have 20x increased risk to non-white races

49
Q

What are the presenting symptoms of melanoma?

A
  • Change in size, shape or colour of pigmented skin lesions
  • Redness
  • Bleeding
  • Crusting
  • Ulceration
50
Q

What are the signs of melanoma on examination?

A
ABCD criteria for examining moles 
A Asymmetry 
B Border irregularity/bleeding 
C Colour variation 
D Diameter over 6mm 
E Elevation
51
Q

What are the investigations for melanoma?

A
  • Excisional biopsy: Dx and determination of Clark’s levels or Breslow thickness
  • Lymphoscinigraphy
  • Sentinel lymph node biopsy
  • Staging: Ultrasound, CT or MRI, CXR
  • Blood: LFT (liver is common site of metastases)
52
Q

What is molluscum contagiosum?

A
  • Condition caused by molluscum contagiosum virus which escapes immune destruction for months to years
53
Q

What is the aetiology of molluscum contagiosum?

A

3 types of lesions

  • MCV 1 and 1v seen in children as result of child-to-child contact or fomites
  • MCV 2 is sexually transmitted and noted in the groin in adults and generalised in immunocompromised people
  • MCV 3 is a rare subtype in any age group
54
Q

What is the epidemiology of molluscum contagiosum?

A
  • No sex or ethnic trend
55
Q

What are the presenting symptoms of molluscum contagiosum?

A
  • Presence of risk factors: close contact with infected indiv, sexual contact with infected indiv, HIV infection, tropical climate
  • Facial or groin distribution of lesions
  • Atopic dermatitis
56
Q

What are the signs of molluscum contagiosum on examination?

A
  • Pearly papule with a central dell
  • Surrounding erythema
  • Pruritis
57
Q

What are the investigations for molluscum contagiosum?

A
  • Clinical dx
  • Curettage biopsy
  • Tzanck stain: purple ovoid keratinocytes
  • Haematoxylin and eosin staining: Henderson-Paterson bodies
  • HIV test
58
Q

What are pressure sores?

A

Skin damage and ulcers caused by pressure on weightbearing areas, typically tissue over bony prominences

59
Q

What is the aetiology of pressure sores?

A

Pressure over susceptible tissues results in impaired perfusion, ischaemia, cell death and skin breakdown

60
Q

What are the risk factors for pressure sores?

A
  • Extrinsic: Pressure, shear, friction, moisture

- Intrinsic: Age, immobility, sensory impairment, incontinence, protein-calorie nutrition

61
Q

What is the epidemiology of pressure sores?

A
  • Common

- 70% in those over 70

62
Q

What are the presenting symptoms of pressure sores?

A
  • Area of erythema or ulcer may be noticed by carer, less frequently the pt may complain of pain in the affected area
  • Predisposing factors should be ascertained
  • Ischaemic injury responsible may have occurred early on in a hosp stay
63
Q

What are the signs of pressure sores on examination?

A

Vulnerable areas are over sacrum, coccyx, ischial tuberosities, greater trochanter malleoli and heels, also the occiput and scapulae

64
Q

What are the investigations for pressure sores?

A
  • Wound swab, FBC, blood cultures if infection suspected

- Plain radiographs, bone or Gallium scans, MRI or needle bone biopsy if underlying osteomyelitis is suspected

65
Q

What is psoriasis?

A

Chronic inflammation skin disease which has characteristic lesions and may be complicated by arthritis

66
Q

What is the aetiology of psoriasis?

A
  • Unknown
  • Genetic, environmental factors and drugs (e.g. may be triggered by streptococcal infections, antimalarial agents, B-blockers, lithium)
67
Q

What are the risk factors for psoriasis?

A
  • Guttae psoriasis: Streptococci sore throat
  • Palmoplantar pustulosis: Smoking, middle-aged women, autoimmune thyroid disease, SAPHO
  • Generalised pustular: Hypoparathyroidism
68
Q

What is the epidemiology of psoriasis?

A
  • Affects 1-2% of population

- Peak age of onset- 20 yrs

69
Q

What are the presenting symptoms of psoriasis?

A
  • Itching or occasionally tender skin
  • Pinpoint bleeding with removing scales (Auspitz phenomenon)
  • Skin lesions may develop at the site of trauma/scars (Koebner phenomenon)
70
Q

What are the signs of psoriasis on examination?

A
  • Discoid/nummular psoriasis: Symmetrical well demarcated erythematous plaques with silver scales over extensor surface
  • Flexural psoriasis: Less scaly plaques in axilla, groins, perianal and genital skin
  • Gluttate: small drop like lesions over trunk, limbs
  • Palmoplantar: Erythematous plaques with pustules distributed over limbs and torso
  • Nail: Pitting, oncholysis, subungual hyperkeratosis, salmon patch on nail
  • Joints: seronegative arthritis
71
Q

What are the investigations for psoriasis?

A

Majority don’t need investigations

  • Gluttate psoriasis: Anti-streptolysin-O tire, throat swan
  • Flexural lesions: Skin swabs (exclude candidiasis)
  • Nail: Analyse nail clippings to exclude onchomycosis
  • Joint involvement: Rheumatoid factor negative, radiographs, sacrolitis
72
Q

What are sebaceous cysts?

A

Epithelium-lined, keratinous, debris-filled cyst arising from a blocked hair follicle
More correctly known as epidermal cyst

73
Q

What is the aetiology of sebaceous cysts?

A
  • Occlusion of the pilosebaceous gland

- Traumatic insertion of epidermal elements into the dermis and embryonic remnants

74
Q

What is the epidemiology of sebaceous cysts?

A

Extremely common any age

75
Q

What are the presenting symptoms of sebaceous cysts?

A
  • Non-tender slow growing skin swelling, often multiple
  • Common on hair-bearing areas of the body, especially face, scalp, trunk or scrotum
  • May become red, hot and tender if superimposed inflammation or infection
76
Q

What are the signs of sebaceous cysts on examination?

A
  • Smooth tethered lump with overlying skin punctum

- May express granular creamy material with an unpleasant smell

77
Q

What are the investigations for sebaceous cysts?

A
  • None usually required

- Skin biopsy of FNA may rarely be necessary to rule out other differentials

78
Q

What is squamous cell carcinoma?

A

Malignancy of the epidermal keratinocytes of the skin

- Marjolin’s ulcer is a squamous cell carcinoma that arises in an area of chronically inflamed/scarred skin

79
Q

What is the aetiology of squamous cell carcinoma?

A
  • Main aetiological risk factor is UV radiation from sunlight exposure, acitinic keratoses
  • Radiation, carcinogens (tar deriratives, cigarette smoke, soot), chronic skin disease, HPV, long term immunosuppression (HIV), DNA repair genetic defects (xeroderma pigmentosum
80
Q

What is the epidemiology of squamous cell carcinoma?

A
  • Second most common cutaneous malignancy
  • Often occurring in middle aged and elderly light skinned individuals
  • Male: Female 2-3:1
81
Q

What are the presenting symptoms of squamous cell carcinoma?

A
  • Skin lesion
  • Ulcerated
  • Recurrent bleeding or non-healing
82
Q

What are the signs of squamous cell carcinoma on examination?

A
  • Variable appearance: ulcerated, hyperkeratotic, crusted or scaly, non healing lesion, often on sun-exposed areas
  • Palpate for local lymphadenopathy
83
Q

What are the investigations for squamous cell carcinoma?

A
  • Skin biopsy: Confirms malignancy and distinguishes it from other skin lesions
  • FNA or lymph node biopsy: if suspicious of metastases
  • Staging: CT and/or MRI, PET scanning
84
Q

What is urticaria

A
  • Also knows as hives
  • Is a skin rash with red, raised, itchy bumps which may also burn or sting
  • Patches often move around
85
Q

What is the aetiology of urticaria?

A
  • Medications: allergic reactions: codeine, ibuprofen, aspirin
  • Food: Allergies: Shellfish and nuts in adults. Shellfish, nuts, eggs, wheat and soy
  • Infection or environmental agent
  • Dermatographic urticaria: marked by appearance of weals or welts on the skin as a result of scratching or firm stroking of the skin
86
Q

What is the epidemiology of urticaria?

A
  • Acute urticaria more common in people with atopy and mostly in children and young adults
87
Q

What are the presenting symptoms of urticaria?

A
  • Welts (raised areas surrounded by red base
  • Itching
  • Swelling that causes pain or burning
  • Signs and symptoms flare with triggers such as heat, exercise and stress
  • Symptoms recur frequently and unpredictably, sometimes months or years
  • Angioedema
88
Q

What are the signs of urticaria on examination?

A
  • Head: areas of alopecia
  • Face: lip or eyelid swelling, oral ulcers and dry eyes
  • Neck: Cervical lymphadenopathy, thyromegaly or thyroid nodules
  • Pharynx: strep throat with injection and tonsillar enlargements with crypts
  • Extremities: angio-oedema and axillary lymphadenopathy
89
Q

What are the investigations for urticaria?

A
  • Strep throat: throat culture
  • Suspected allergic urticaria: skin prick testing
  • Suspected aquagenic urticaria: Lukewarm water immersion