Derm 101 Flashcards
Define primary lesions
Directly associated with the disease process
Define secondary lesions
Modifications of primary skin lesions
Primary lesion: Macule (definition)
Non-palpable flat lesion of less than 0.5 cm in diameter (e.g. cafe-au-lait macule)
Primary lesion: Patch (definition)
Non-palpable flat lesion of more than 0.5 cm in diameter (e.g. vitiligo)
Primary lesion: Papule (definition)
Raised lesions, usually a different colour than surrounding skin (can also be the same colour) < 0.5 cm. (eg. molluscum)
Primary lesion: Plaque (definition)
raised lesions, usually a different color than surrounding skin, but can be the same, > 0.5 cm (e.g. psoriasis).
Primary lesion: Nodule (definition)
Raised, solid lesion with DEPTH, <0.5 cm (e.g. basal cell carcinoma)
Primary lesion: Tumour (definition)
Raised, solid lesion with DEPTH, >0.5cm (e.g. basal cell carcinoma)
Primary lesion: Vesicle (definition)
Raised, fluid filled lesion, <0.5cm (e.g. herpes zoster, small blisters)
Primary lesion: Bulla (definition)
Raised, fluid-filled lesion, >0.5 cm (e.g. bullous phemphigoid, large blisters)
Primary lesion: Pustule (definition)
Raised, pus-filled lesion (e.g. acne)
Primary lesion: Wheal (definition) (4)
- Any shape or size
- Key feature: lasts less than 24h!!!
- Accompanied by edema & erythema
- Usually seen in urticaria
Primary lesion: Cysts (definition)
Raised, fluid/substance-filled lesion encapsulated by true epithelium (e.g. epidermoid cyst)
2 categories of secondary lesions
- Damaged or diminished skin surface
- Augmented or increased skin surface
Secondary lesion: Scale (definition)
Desquamation and flakes arising from the stratum corneum (e.g. tinea pedis i.e. athlete’s foot)
Secondary lesion: Crust (definition)
Hardened deposit from serum, blood or pus (e.g. impetigo)
Secondary lesion: Atrophy (definition)
Lack of substance, failure of tissue to form or wasting of tissue. Affected tissue is thinner or depressed compared to surrounding skin (e.g. striae or stretch marks).
Secondary lesion: Erosion (definition)
Lack of substance, moist circumscribed depression due to loss of all or part of the epidermis
Secondary lesion: Ulcer (definition)
Lack of substance, circumscribed depression due to loss of entire epidermis and all or part of the dermis (e.g. diabetic ulcer)
What is a TBSE
Total body skin exam: ideal physical examination in dermatology
In the context of a TBSE, “skin” includes… (3)
hair, nails, visible mucosa
What is Wood’s light used for?
To assess pigmentation and presence of certain infections, e.g. vitiligo & erythrasma.
Vitiligo appearance under Wood’s light
Vitiligo appears as white patches under Wood’s light (autoimmune attack on melanocytes causes discoloration)
Erythrasma appearance under Wood’s light
Characteristic coral red appearance under Wood’s light (bacterial infection)
The purpose of a dermoscope is…
magnification (to see details not visible to the naked eye)
What is the purpose of patch testing?
It is done when you suspect allergic contact dermatitis.
3 forms of skin scraping (diagnostic studies) and their pupose
- Potassium hydroxide: to confirm fungal infections
- Cytology: to look at discrete cells under microscope
- Cultures: to confirm infectious etiology (viral, bacterial, fungal)
Hypopigmentation vs depigmentation
Hypopigmentation: some pigment is present, but less than in surrounding healthy skin
Depigmentation: no pigment is present, sharp contrast with surrounding healthy skin (e.g. vitiligo, where immune cells attack melanocytes)
