L5 - Skin Changes Flashcards
What is a macule?
Flat, non palpable lesion usually <10mm (1cm) in diameter
Represents a change in color and are not raised or depressed compared to the skin surface
What is a patch?
A large macule
>1cm (10mm)
What are some examples of macules?
Freckles, flat moles, tattoos, port wine stains, rashes of rickettsial infections, rubella, measles (can also have papules and plaques), and some allergic drug eruptions
What is a papule?
Elevated lesions usually <10mm in diameter than can be felt or palpated
What are some examples of papules?
Nevi, warts, lichen planus, insect bites, sebhorreic keratosis, actinic keratosis, some lesions of acne, and skin cancers
What are plaques?
Palpable lesions >10mm in diameter that are elevated or depressed compared to the skin surface
May be flat topped or rounded
What are nodules?
Firm papules or lesions that extend into the dermis or subcutaneous tissue
Examples include cysts, lipomas and fibromas
What is a vesicle?
Small, clear, fluid filled blisters <10mm in diameter
Characteristic of herpes infections, acute allergic contact dermatitis, and some auto immune blistering disorders (e.g. dermatitis herpetiforms)
What is a pustule?
Vesicles that contain pus
Common in bacterial infections and folliculitis and may arise in some inflammatory disorders including pustular psoriasis
What are bullae?
Clear fluid filled blisters >10mm in diameter
What can cause bullae?
May be caused by burns, bites, irritant contact dermatitis or allergic contact dermatitis, and drug reactions
Classic autoimmune bullous diseases include pemphigus vulgaris and bullous pemphigoid
May also occur in inherited disorders of skin fragility
What are petechiae?
Non-blanchable punctate foci of hemorrhage
Causes include platelet abnormalities (e.g. thrombocytopenia, platelet dysfunction, vasculitis, and infections (e.g. meningococcemia, Rocky Mountain spotted fever, other rickettsioses)
What are purpura?
Palpable purpura are considered the hallmark of leukocytoclastic vasculitis
Palpable: think vasculitis
Non palpable purpura are usually considered simple hemorrhage or micro vascular occlusion with ischemic hemorrhage
May indicate coagulopathy
List secondary skin lesions
Scale, crust, excoriation, erosion, ulcer, fissure, lichenification, atrophy
What is a scale?
Excessive accumulation of stratum corneum (e.g. flakes of skin)
What is crust?
Dried accumulation of body fluids, can be yellow (Serous) or red (hemorrhagic)
What is excoriation?
Linear defects in the epidermis often caused by scratching
What is erosion?
Loss of epidermis without loss of dermis
What is an ulcer?
Full thickness destruction of the epidermis into the underlying dermis
What is a fissure?
Liner break in the epidermis usually along skin lines
What is lichenification?
Visible thickening of the skin resulting in accentuated skin fold markings
What is atrophy?
Acquired loss of substance
May appear as a depression in the epidermis
What are some ways a lesion can be characterized?
Linear, annular, nummular, target (bulls eye or iris) lesions, serpiginous lesions, reticulated lesions, herpetiform
What is a linear lesion?
Take on the shape of a straight line
What is an annular lesion?
Rings with central clearing
What is a nummular lesion?
Circular or coin shaped
What is a target (bulls eye or iris) lesion?
Appear as rings with central duskiness and are classic for erythema multiforme
What are serpingous lesions?
Have linear, branched and curving elements
What are reticulated lesions?
Have a lacy or networked pattern
What are herpetiform lesions?
Describes grouped papules or vesicles
What are some causes for a maculopapular or papular rash?
Viral, bacterial, toxin induced (poison ivy/oak) or drug effect (allergic reaction)
What are important things to consider when evaluating a maculopapular or papular rash?
Morphology (flat, raised, fluid filled)
Color
Secondary changes (crust, scale, erosion, ulceration)
Distribution (localized, diffuse, dermatomal, flexural)
Red flags (skin pain, blisters/desquamation, mucus membrane involvement, extensive body surface area (BSA), purpura)
Erythema migrans is usually due to what?
Borrelia burgdoferi (Lyme disease) Bulls eye lesion
What is acanthosis nigricans?
Hyperpigmentated velvet like plaques on lateral neck of a pt
Associated with DM
What is pretibial myxedema?
Pink waxy indurated plaque on lower leg
Associated with Graves’ disease and hyperthyroidism
What is vasculitis?
Refers to a group of disorders characterized by inflammation and damage in blood vessel walls
May be limited to skin or may be a multi system disorder
Classified according the vessel type and size
Small blood vessels are found where?
In the epidermis
Medium sized vessels are found where?
In the dermis
What are some disorders associated large vessel vasculitis?
Giant cell arteritis
Polymyalgia rheumatica
Takayasu arteritis
Aortitis
What are the most common medium/small artery vasculitides?
Polyarteritis nodosa (only one not associated with ANCA auto-Abs)
Eosinophilic granulomatosis with polyangitis
Granulomatosis with polyangitis
Microscopic polyangitis
What are some other important small vessel vasculitides?
Hypersensitivity vasculitis
IgA vasculitis (formerly HSP)
Cryoglobulinemia
Anti glomerular basement membrane disease/Good pasture syndrome
