DERM 06: Diagnosing Common Skin Conditions

Question 1

What are the steps to clinical diagnosis in dermatology?

Answer 1

• basic morphologic features
• cutaneous reaction patterns
• diagnosis

Question 2

What are the 5 basic dermatologic morphologic terms?

Answer 2

• flat, non-palpable spots
• elevated lesion
• lesions with significant depth
• fluid-filled lesions
• open wounds

Question 3

Flat, Non-Palpable Spots (2)

Answer 3

• macule: small spot, ≤ 1 cm
• patch: large spot, > 1 cm – arises de novo or through coalescence of macule

Question 4

Elevated Lesion (2)

Answer 4

• papule: small bump, ≤ 1 cm
• plaque: large bump, > 1 cm – arises de novo or as a result of coalescence of papule

Question 5

Lesions with Significant Depth (1)

Answer 5

• nodule: usually > 1 cm, solid and deep, located in dermis and/or subcutis – palpable

Question 6

Fluid-Filled Lesions (3)

Answer 6

• vesicle: small bubble, ≤ 1 cm – clear, fluid-filled
• bulla: large bubble, > 1 cm – clear, fluid-filled, ‘vesiculobullous’ lesions are almost always clinically important
• pustule: turbid, pus-containing bubble (ie. leukocytes) – pus does not always indicate infection

Question 7

Open Wounds (2)

Answer 7

• erosion: superficial, loss of epidermis or mucosa only, heals without scarring
• ulcer: deeper, partial or complete loss of dermis or submucosa, usually heals with scarring

Question 8

What are the secondary features of skin conditions? (4)

Answer 8

• scale
• crust (scab)
• lichenification
• excoriation

Question 9

What are scales?

Answer 9

accumulation or excess shedding of stratum corneum

Question 10

What are crusts (scabs)?

Answer 10

dried exudate (serum, blood, pus) on skin surface

Question 11

What is lichenification?

Answer 11

accentuation of skin lines or creases due to repeated rubbing or scratching

Question 12

What is excoriation?

Answer 12

loss of skin due to scratching or picking

Question 13

Describe characteristics of rashes.

Answer 13

• red, usually itchy
• acute, subacute, or chronic
• distribution may be widespread or limited
• each skin reaction pattern can arise from a range of different causes

Question 14

What are the 6 rash reaction patterns?

Answer 14

• papulosquamous
• eczematous
• urticarial
• excanthematous
• vesiculobullous
• purpuric

Question 15

What is the papulosquamous rash reaction pattern?

Answer 15

• combination of raised lesions (papules and/or plaques) with scale
• varying degrees of pruritus
• epidermal proliferation combined with inflammation

Question 16

What disease has a papulosquamous rash reaction pattern?

Answer 16

psoriasis

• 5 cardinal signs: plaque, well-circumscribed, bright red colour, silvery scale, symmetric

Question 17

What is the eczematous rash reaction pattern?

Answer 17

(also called dermatitis)

• pruritus almost always present – scratching results in secondary features
• vesicles may be present during acute phase
• varying degrees of erythema
• multiple different causes

Question 18

What is the urticarial rash reaction pattern?

Answer 18

(also known as hives or wheals)

• pruritic, pink, edematous papules and/or plaques that are well-circumscribed
• individual lesions are transient and usually last for a few hours or less

Question 19

What is the excanthematous rash reaction pattern?

Answer 19

• acute and usually abrupt onset of red macules and papules that coalesce to involve a large skin surface
• eruption often appears blotchy
• scaling may develop as the rash evolves
• often associated with systemic symptoms (ie. fever, malaise, respiratory and GI symptoms)
• persists > 24 hours
• if more serious, may evolve into vesicles and bullae
• usually due to either viral infections or drugs

Question 20

What is the vesiculobulous rash reaction pattern?

Answer 20

• fluid-filled skin lesions
• if vesicles or bullae break and are no longer intact, erosions and crusts will be present
• pruritus and/or pain
• may have coincidental involvement of mucosal surfaces (ie. oral, ocular, and anogenital surfaces)

Question 21

What is the purpuric rash reaction pattern?

Answer 21

• non–blanching purple skin lesions of variable size
• purpura arises from problems due to platelets, coagulation factors, or blood vessel wall damage

Question 22

Describe spots, sores, lumps, and bumps.

Answer 22

• usually solitary
• usually not inflamed (note that spots, sores, lumps, and bumps can also be due to infectious, inflammatory/immunologic, trauma, toxins and allergens)

Question 23

What are the major risk factors for skin cancer?

Answer 23

• prior personal history of skin cancer or pre-cancer
• excessive prior sun exposure
• presence of multiple skin moles
• presence of abnormal-looking moles
• family history of skin cancer
• chronic systemic immunosuppression

Question 24

When should you be suspicious for skin cancer?

Answer 24

• sore that does not heal in reasonable period of time
• new or changing moles
• new or changing skin growths
• ABCDE
• most skin cancers are first detected by family members

Question 25

How can you decrease your risk for skin cancer?

Answer 25

- early medical evaluation of suspicious growths - avoid being in sun from 11-3 - cover up with hats and clothing - seek shade - avoid tanning outdoors or in salons - use sunscreens

Question 26

What are the 3 main types of skin cancer?

Answer 26

- basal cell carcinoma - squamous cell carcinoma - malignant melanoma

Question 27

What is basal cell carcinoma?

Answer 27

most common form of skin cancer - translucent skin-coloured nodules - may be eroded or ulcerated - prominent superficial blood vessels (telangiectasia) - low risk of spreading to other organs, but can be locally invasive

Question 28

What are the different types of basal cell carcinoma?

Answer 28

- nodular (translucent, skin-coloured nodule) - superficial (often flat, scaly, inflamed) - sclerosing (resembles scar) - pigmented

Question 29

What is squamous cell carcinoma?

Answer 29

- solid skin tumours - may often be volcano-shaped - thick overlying scale - higher risk for spread to other organs

Question 30

What is actinic keratosis?

Answer 30

pre-skin cancer (may evolve into squamous cell carcinoma) - scaly, skin-coloured, pink, or red spots - presence indicates significant sun damaged-skin

Question 31

What is malignant melanoma?

Answer 31

- most dangerous form of skin cancer - increasing incidence - highest potential for spread to other organs - ‘curable’ only if detected early - prognosis depends on microscopic depth in skin - ACBDE rule: asymmetry, border, colour, diameter, eccentric evolving

Question 32

What are the 4 categories of skin disorders

Answer 32

- infectious - inflammatory-immunologic - trauma, toxins, and allergens - neoplasia

Question 33

What is the clinical management strategy for infectious skin disorders?

Answer 33

- antimicrobial therapy - vaccines and infection control

Question 34

What is the clinical management strategy for inflammatory-immunologic skin disorders?

Answer 34

- glucocorticoids - immunomodulators

Question 35

What is the clinical management strategy for trauma, toxin, and allergen skin disorders?

Answer 35

- remove offending agent - repair injury

Question 36

What is the clinical management strategy for neoplasia skin disorders?

Answer 36

- surgery - radiation - chemotherapy - immunotherapy

Question 37

What is neoplasia?

Answer 37

- formation or presence of new, abnormal growth of tissue - usually presents as solitary lumps, bumps, spots, and sores

Question 38

What are the two key rules of thumb to consider about skin disorders?

Answer 38

- always think of drug eruptions (see trauma, toxins, and allergens column in chart), adverse cutaneous drug reactions - is the skin problem limited to the skin or does it indicate an internal medical problem