Dermatology Flashcards
What to ask in history of rash - HPC
- Relieving/exacerbating factors
- Associated symptoms: itch, pain, burning
- Systemic complaints
- How long: duration, persistent intermittent
- Treatments tried to date
Relevant PMH for history of rash
- Diabetes
- Thyroid
- Atopic disorders – eczema, asthma, hayfever
What drugs are associated with psoriasis (cardiac, neuro)
beta blockers, lithium
Relevant family hx for history of rash
- Atopic disorders
* Skin cancers
What to ask in history of lesion - HPC
- Onset: Initial appearance + evolution, Duration
- Character: Pain, itch, discharge, bleeding
- Skin type (Fitzpatrick)
- UV exposure – sunbeds, occupation, travel
- History of skin cancer
ABCDE of describing a pigmented lesion
- Asymmetry
- Border: smooth edge vs craggy
- Colours: how many
- Diameter
- Elevation and evolution
What is a flat discoloured lesion <5mm called
Macule
What is a flat discoloured lesion >5mm called
Patch
What is a solid elevation <5mm called
Papule
What is a solid elevation >5mm called
Nodule
What is a clear fluid-filled lesion <5mm called
Vesicle
What is a clear fluid-filled lesion >5mm called
Bullous (blister)
What is a pus-filled lesion <5mm called
Pustule
What is a scaly raised lesion >5mm called
Plaque
What autoimmune condition is pyoderma gangrenosum associated with
IBD: Crohn’s and Ulcerating Colitis
Describe the Koebner phenomenon.
In which type of pt does it occur most often
- Appearance of linear skin lesions exacerbated by trauma eg scratching, surgery
- Happens most often in people with psoriasis
Name a dermatological emergency
Erythroderma
What skin condition causes target lesions
Erythema multiforme
Commonest cause of erythemia multiforme
Viral infection
second most common cause is allergy
Which layer of skin does UVA damage
Epidermis
Which layer of skin does UVB damage
Dermis
Which layer of skin does infrared damage
Deep dermis and subcutaneous tissue
What are cherry angiomas
- in which age group are they more common
- do they require urgent referral
Benign blood vessel lesion
Common in elderly
Benign, harmless
What are 3 pre-malignant versions of SCC
- Actinic keratosis
- Bowen’s disease
- Cutaneous horn
What is the pre-malignant version of melanoma
Lentigo maligna
What is the pre-malignant version of BCC
BCC does NOT have a pre-cancer version
List the skin cancers from the highest grade to lowest
- Melanoma
- SCC
- BCC
Main features of BCC
- Slow growing
- Pearly translucency with dilated blood vessels running over (telengectasia)
- Rolled-edge
- Ulcerated
Main features of SCC
- Faster growing
- Either raised bump or red, scaly skin patch
- May have crusty edges or blood
- tends to occur on sun-exposed areas
Common sites of melanoma
- for men
- for women
Men: back
Women: legs
What are common sites for acral lentiginous melanoma
- under nail
- palms
- soles
4 types of exogenous eczema
- irritant
- allergic
- photodermatitis
- dust mite allergy
What autoimmune condition is associated with erythema nodosum
IBD (both Crohn’s and UC)
What other 3 findings might one find in someone who has cutaneous vasculitis
(think of other systems associated with microvascular problems)
- Eye: Roth’s spots
- Kidney: Microscopic haematuria
- Spleen: Splenomegaly
Difference between irritant and allergic eczema
- timing
- exposure
Irritant: immediate inflammatory reaction, no prior exposure required
Allergic: slow reaction, usually after prolonged exposure
Difference between type 1 and 4 allergy
- cells involved
- how to test
- timing
- result of exposure to allergen
Type 4:
- T lymphocyte response
- Patch test
- Immediate reaction
- Can cause anaphylaxis
Type 1:
- IgE response to soluble antigen
- Blood test
- Delayed reaction
- Causes allergic contact dermatitis
Is allergic eczema type 1 or 4 allergy
type 4
Is dust mite allergy type 1 or 4 allergy
type 1
8 Types of endogenous chronic eczema
- atopic dermatitis
- seborrheic dermatitis
- discoid eczema
- pompholyx
- varicose eczema
- asteatotic eczema
- lichen simplex chronicus
- eczema herpeticum
Where does eczema tend to present in children
face, flexors
Where does eczema tend to present in adults
chest, lower back
Risk factors for eczema
- genetics
- environment
- endogenous (associated with atopy)
What is pompholyx
Small stingy blisters on hands and feet which burst and dry up, become vesicles
What is asteatotic eczema
Eczema with a fish scale/ mosaic type pattern
Where does lichen simplex chronicus tend to occur
inner ankle
inner elbow
nape of neck
What causes eczema herpeticum
What is a serious risk of this condition
HSV colonisation on top of eczema
Risk of corneal ulceration
How to differentiate eczema vs psoriasis
- borders
- itchiness
- appearance
- where it occurs
Borders: diffuse (eczema) vs well-defined (psoriasis)
Itchiness: Eczema more itchy
Appearance: can see scratch marks (eczema) vs white silvery skin (psoriasis)
Where: flexor surface (eczema) vs extensor surface (psoriasis)
Conditions associated with psoriasis
- psoriatic arthritis
- IBD
- uveitis
- Coeliac’s
- metabolic syndrome
What are the 6 components of metabolic syndrome
- obesity
- hypertension
- high cholesterol
- gout
- CVD
- T2DM
pathology of psoriasis:
keratinocytes
- keratinocytes normally take 28 days to migrate to skin surface (enough time to lose stickiness)
- take 4 days in psoriasis
- keratinocytes still sticky, stick together as plaques
What type of psoriasis appears after acute infection eg strep throat
Guttate
Describe Fitzpatrick skin types 1-6
TYPE 1: Highly sensitive, always burns, never tans.
TYPE 2: Very sun sensitive, burns easily, tans minimally.
TYPE 3: Sun sensitive skin, sometimes burns, slowly tans to light brown.
TYPE 4: Minimally sun sensitive, burns minimally, always tans to moderate brown.
TYPE 5: Sun insensitive skin, rarely burns, tans well.
TYPE 6: Sun insensitive, never burns, deeply pigmented.
