Dermatology Flashcards
What is a basal cell carcinoma? And what features does it have?
It is a skin malignancy arising from epidermal keratinocytes.
Features:
- slow growing
- locally invasive
- rarely metastasises
What are the risk factors for basal cell carcinoma?
- sun exposure
- UV radiation
- frequent and severe sunburn
- tar
- arsenic
- photosensitising pitch
What is the epidemiology of basal cell carcinoma?
common in fair skinned people
usually in areas exposed to sun light
elderly (rare before 40 years of age)
What are common areas affected by BCC?
face
scalp
ears
trunk
describe a typical basal cell carcinoma
lesion with:
- rolled edge
- pearly appearance
- telangiectasia
What are the types of basal cell carcinoma and which one is the most common?
nodulo-ulcerative (most common, typical appearance)
morphoeic (expanding, yellow/white plaque, more aggressive than nodulo-ulcerative)
superficial (usually on trunk, pink/brown)
pigmented
what is this?
basal cell carcinoma
what is this?
morphoeic basal cell carcinoma
What is contact dermatitis?
An inflammatory skin reaction arising due to an external stimulus which is acting as an allergen or irritant
What are the types of contact dermatitis?
- allergic contact dermatitis
- delayed type IV hypersensitivity reaction
- irritant contact dermatitis
- inflammation usualyl due to damage to the skin by extrinsic factor e.g. chemicals
What are some allergens and irritants that might cause contact dermatitis
- ALLERGENS
- cosmetics
- metals
- topical medications
- textiles
- IRRITANTS
- detergents
- soaps
- solvents
- powders
what are of the body is most commonly affected by contact dermatitis?
hands
describe the appearance of an area of contact dermatitis?
- redness
- vesicles + papules in the area
- crusting and papules of the skin
- itching
- pain
what is this?
contact dermatitis
what is eczema?
it is a pruritic papulovesicular skin reaction to endogenous and exogenous agents. it is a TYPE IV HYPERSENSITIVITY reaction
What is the pathophysiology of eczema?
allergen → antigen presenting cell →T helper 2 cells stimulate B cells → IgE production increased → mast cell and basophils are activated. → sensitisation
secondary allergen exposure → mast cell degranulation→ inflammation → vasodilation → dry + scaly skin with reduced barrier function
what is the epidemiology of atopic eczema?
Onset usually in the first year of life with childhood incidence around 10-20%
What are the types of eczema?
contact
atopic
seborrhoiec
What are features of eczema?
- itching (worse at night)
- heat
- tenderness
- redness
- weeping
- crusting
- affecting flexors and exposed areas of skin
- Hx of atopy [personal or family]
ACUTE: poorly demarcated erythematous + oedmatous dry scaly patches. may have papules + vesicles. excoriation marks
CHRONIC: thick epidermis, skin lichenification, fissures, change in pigmentation
fill in the table
what investigations might you perform to confirm a diagnosis of eczema ?
skin patch testing if contact eczema
lab testing with IgE for atopic eczema
otherwise clinical diagnosis
what is erythema multiforme?
an acute hypersensitivity reaction affecting the skin and mucous membranes
what is stevens-johnson syndrome?
a severe form of erythema multiforme meaning a severe hypersensitivity reaction affecting the skin and mucous membrane.
for diagnosis > 2 mucous membranes must be affected.
features: bullous lesions + necrotic ulcers
How does the areas of body affected by atopic eczema change with age?
what is this?
eczema
what is the pathophysiology of erythema multiforme?
The basal epidermal cells degenerate and vesicals form between basement membrane cells. lymphocyte invasion to tissue also occurs. Precipitating factors identified in only 50% of cases
What are some precipitating factors for erythema multiforme?
DRUGS - penicillin, phenytoin
INFECTION - HERPES (main factor), EBC, chlamydia, adenovirus
INFLAMMATORY - RA, SLE, sarcoidosis, ulcerative colitis
MALIGNANCY - haematological
radiotherapy
what is the epidemiology of erythema multiforme?
2M: 1 F
children + young adults but can affect all ages
What are the clinical features of erythema multiforme?
- classic target (bull’s eye) lesions
- vesicles/bullae
- urticarial plaques
- often symmetrical extending over limbs including palms, soles + extensors
what is this?
erythema multiforme
what is this?
erythema multiforme
What is erythema nodosum?
It is an inflammation of the subcutaneous fat tissue which presents with red/violet subcutaneous nodules
What is erythema nodosum associated with?
INFECTION = group A beta-haemolytic streptococcus, EBV, histoplasmosis
SYSTEMIC DISEASE = sarcoidosis, IBD, behcet’s disease
MALIGNANCY = leukaemia, hodgkin’s lymphoma
DRUGS = penicillin, OCP
PREGNANCY
What is the epidemiology of erythema nodosum?
3F:1M
young adults most commonly affected
what are the clinical features of erythema nodosum?
tender red/violet nodules bilaterally on both shins
sometimes thighs + forearms
systemic: fever, anorexia, weight loss, arthralgia (tender painful joints on movement)
what investigations may help confirm a diagnosis of erythema nodosum?
Bloods -> anti-streptolysin O titres, FBC, CRP, ESR, U&E, serum ACE (sarcoidosis)
throat swab + culture
mantoux test
CXR
what is this?
erythema nodosum
what is this?
erythema nodosum
what is a lipoma?
it is a slow-growing benign adipose tumous usually found in the subcutaneous tissue.
What is the epidemiology associated with lipomas?
most common in 40-60s
relatively common condition
what are the clinical features of a lipoma?
- soft or firm nodule with smooth surface. dough feel
- most < 5cm
- mobile
- most are asymptomatic
- pain may be caused by compression of nearby nerves
what is a melanoma?
It is a malignancy arising from neoplastic transformation of melanocytes. it is the leading cause of death from skin disease
What are the four histopathological types of melanoma?
- SUPERFICIAL SPREADING
- most common
- arising from existing naevus expanding radial before vertically
- NODULAR
- aggressive
- arise de novo
- vertical growth, no radial expansion really
- LENTIGO MALIGNA
- common in elderly with sun damage
- large flat lesions often on face
- ACRAL LENTIGINOUS
- palms, soles, subungal areas
- usually in non-white populations
what is the most common type of melanoma?
what is the most aggressive type?
common = superficial spreading
aggressive = nodular
how do you assess a lesion suspected of being a melanoma?
Asymmetry
Border - irregular
Colour - variation within lesion
Diameter - > 6/7mm
Evolution - elevation and progression/change
what investigations might you perform if you suspect melanoma?
excisional biopsy for histology
lymphoscintography + sentinel lymph node biopsy - locate nodes and check for mets
staging scans
bloods - LFTs as common met site
where does melanoma commonly metastasise to?
liver
what is this?
melanoma
What is molluscum contagiosum?
a skin infection caused by a pox virus usually transmitted by direct skin contact
what are risk factors for molluscum contagiosum?
actopic eczema
children
immunocompromised
what is the epidemiology of molluscum contagiosum?
common, usually affects those < 15 years but can affect all ages
most do not seek medical attention
what are the clinical features of molluscum contagiosum?
incubation for 2-8 weeks
- most are asymptomatic
- symptoms:
- tenderness
- pruritus
- eczema around lesions
- lesions are firm, smooth and umbilicated papules 2-5mm
- children = trunk + extremities ; adults = lower abdomen, genital areas, inner thighs
what is this?
molluscum contagiosum
what is psoriasis?
chronic inflammatory skin condition characterised by lesions. May be complicated by arthritis (psoriatic arthritis)
Are there risk factors for different types of psoriasis?
guttate psoriasis - strep sore throat
palmoplanter psoriasis - smoking, middle aged F, autoimmune thyroid disease
generalised pustular psoriasis - hypoparathyroidism
what is the peak age of onset for psoriasis?
20
what are the presenting features of psoriasis?
- itching + tender/burning skin
- koebner phenomenen - psoriasis lesions developing near sites of trauma/scars
- well demarcated erythemaous scaly plaques
- common on extensor surfaces + scalp
- auspitz sign - scratching and gentle removal of scales cause capillary bleeding
How many psoriasis patients have psoriatic arthritis?
what are the fatures of psoriatic arthritis?
5-8% have it
CLINICAL FEATURES
- asymmetrical oligomonoarthritis
- symmetrical polyarthritis
- distal interphalangeal joint predominance
- arthritis mutilans (flexion deformity of DIP joint)
- psoriatic spondylitis
what is this?
psoriasis
what is this?
GUTTATE PSORIASIS
small dop-like lesions over the trunk and limbs
what is this?
PALMOPLANTER PSORIASIS
erythematous plaques with pustules on palms and soles
what is this?
FLEXURAL PSORIASIS
psoriasis affecting flexor surfaces such as axilla, groin, perianal, genital skin
the plaques are less scaly
what is a sebaceous cyst?
an epithelium lined, keratinous, debris-filled cyst arising from a blocked hair follicle (aka epidermal cyst)
what are the clinical features of a sebaceous cyst?
non tender slow growing skin swelling. usually multiple
common in hair growing regions of the body (think face, scalp, trunk and scrotum)
what are the clinical features of a sebaceous cyst?
smooth tethered lump
overlying skin punctum
may discharge a granular creamy material that smells foul
What are the management options for a sebaceous cyst?
conservative - leave alone if causing no pt distress
surgical - removal of cyst with LA
medical - Abx if infeciton present
what are the possible complications of a sebaceous cyst?
infection
abscess formation
recurrence
ulceration
what is squamous cell carcinoma?
a malignancy of epidermal kertinocytes of the skin
what is this?
sebaceous cyst
what are the risk factors for sqaumous cell carcinoma?
UV radiation
radiation
carcinogens
chronic skin disease
HPV
long-term immunosuppression
what is the epidemiology of squamous cell carcinoma?
20% of all skin cancers
mainly affects MIDDLE-AGES + ELDERLY
light skinned at higher risk
2-3M:1F
What are the presenting features of a squamous cell carcinoma?
- keratotic (scaly, crusty) ill defined nodule which may ulcerate
- recurrent bleeding
- non-healing
- often on sun-exposed skin areas
what is this?
squamous cell carcinoma
what is this?
squamous cell carcinoma
what is urticaria?
itchy red blotchy rash from swelling of the superficial layers of the skin.
what is the pathophysiology of urticaria?
it is a hypersensitvity reaction with mast cell activation leading to histamine release. the vasodilation of the vessels causes the erythematous appearance of the skin.
if the oedema occurs in deeper tissue such as the lower dermis or subcut then it is ANGIOOEDEMA
what is acute urticaria and what are potential triggers?
acute urticaria is urticare where symptom onset is rapid but resolves within 48 hours
triggers: allergens, viral infection, skin contact with chemicals, physical stimuli
what is chronic urticaria and what are potential triggers?
chronic urticaria refers to patiens whose symptoms last longer than 6 weeks
triggers: chronic spontaneous urticaria, autoimmune
what are the clinical features of urticaria?
central itchy white papule or plaque surrounded by erythematous skin.
lesions vary in size + shape
may have angiooedema
what is this?
urticaria
what is this?
urticaria
management of chronic plaque psoriasis
- topical potent corticosteroid (betamethasone) + topical calcipotriol (Vit D)
- Vitamin D analogue BD + OD steroid
- BD steroid + BD vit D + coat tar
- phototherapy - narrowband UVB
- systemic - methotrexate, ciclosporin, infliximab
