1.1 Elementary phenomena on the skin.

Question 1

What are primary lesions?

Answer 1

• lesions that are a diret result of the disease
• macules, papules, plaques, patches, nodules, tubers, pustules, wheals, bullas, vesicles, cysts

Question 2

What are secondary lesions?

Answer 2

• lesions developing from a primary lesion or due to patient activities
• erosions, ulcers, excoriations, fissures, crusts, scales, fistulas, lichenification, atrophy, scars

Question 3

What are macules?

Answer 3

• hypopigmented/hyperpigmented skin lesion that is non-palpable (has no elevation)
• <1cm (>1cm = patch)

Question 4

What are exogenous pigments that cause macules?

Answer 4

• tattoo dyes
• gunpowder
• carotene

Question 5

What are endogenous pigments that cause macules?

Answer 5

• melanin
• lipofuscin
• hemoglobin
• bilirubin

Question 6

What are examples of macules?

Answer 6

• Morphea: localized scleroderma; vessels get compressed due to increased keratin production resulting in improper melanin delivery
• lentigo senilis: lipofuschin brown spots commonly on the face due to sun exposure
• vitiligo segmentalis: immune system destroys melanocytes resulting in hypopigmentation
• subungual melanoma: melanin seen

Question 7

What are papules?

Answer 7

• cellular infiltration in the papillary dermis (epidermis)
• always palpable (elevated), <1cm
• inflammatory/tumorous
• popular examthema is a rash consisting of papules

Question 8

What are examples of papules?

Answer 8

• psoriasis guttate: non-contagious autoimmune disease, usually triggered by bacterial infection
• pigmented nevi: (aka mole) due to local proliferation of melanocytes
• lichen ruber planus: autoimmune disease against keratinocytes

Question 9

What are plaques?

Answer 9

• cellular infiltration of the papillary dermis
• always palpable (elevated), >1cm diameter
• erythroderma: affects the entire body surface
• group of papules together

Question 10

What are some examples of plaques?

Answer 10

• psoriasis vulgaris
• erythema chronicum (ie. borreliosis)

Question 11

What are nodules?

Answer 11

• cellular infiltration in the reticular dermis and subcutis
• usually >2cm
• usually not elevated but is palpable
• not spherically shaped

Question 12

What are examples of nodules?

Answer 12

• erythema nodosum
• lupus panniculitis

Question 13

What is tuber?

Answer 13

• cellular infiltration in the reticular dermis and subcutis
• spherically shaped, highly elevated lesions that are firm upon palpations
• frequent caseation, ulceration and scarring
• ie. cutaneous tuberculosis

Question 14

What is gumma?

Answer 14

like tuber but seen in tertiary syphilis

Question 15

What is a tumor?

Answer 15

• tumor cell infiltration in any layer of the skin
• ie. malignant melanoma, basal cell carcinoma

Question 16

What is urticaria?

Answer 16

• circumscribed edema of the dermis
• can be erythematous due to vessel dilation
• may be due to an allergic reaction or an acute infection
• characteristically disappears within 24 hours
• ie. urticaria factitia, cold urticaria

Question 17

What is a vesicle?

Answer 17

• cavity of <0.5cm within or below the epidermis, filled with serous/hemorrhagic fluid
• usually elevated
• no epithelial wall

Question 18

What are examples of vesicles?

Answer 18

• herpes labialis
• dermatitis
• acute contact dermatitis
• herpetiformis
• hand-foot-mouth disease

Question 19

What is a bulla/blister?

Answer 19

• > 0.5 cm
• circumscribed fluid-filled lesion
• ie. pemphigus vulgaris, bullous pemphigoid

Question 20

What is a pustule?

Answer 20

• like a vesicle/bulla but filled with pus and can be found on any layer of skin
• usually elevated
• yellow color due to WBC’s
• not always due to infections

Question 21

What are examples of pustules?

Answer 21

• acne vulgaris
• furuncle
• pustular psoriasis

Question 22

What is a cyst?

Answer 22

• cavity (closed sac) in the skin that contains air or serous, pus or hemorrhagic fluid or semi-solid material like sebum
• covered by an epithelial wall
• often due to blockage of sebaceous glad duct leading to sebum buildup and then rupture/inflammation
• ie. epidermal cyst

Question 23

What is an ulcer?

Answer 23

• lack of layers of skin due to necrosis
• units under the skin are visible
• necrosis of tuber/gumma/tumor
• ie. diabetic leg ulcer

Question 24

What is erosion?

Answer 24

• due to ruptured vesicle/blister or physical abrasions
• superficial denudation of the epidermis: sharply defined, erythematous, often oozing serum

Question 25

What are examples of erosion?

Answer 25

• bullous pemphigoid
• pemphigus vulgaris
• contagious impetigo

Question 26

What is excoriation?

Answer 26

erosion or ulcer due to patient scratching

Question 27

What is a fissure?

Answer 27

• vertical cleft in the skin, extending into the dermis
• usually develops from chronic plaques
• develops spontaneously; surgical wounds are not fissures

Question 28

What is atrophy?

Answer 28

• partial or complete wasting away (shrinking, involution, incomplete development) of the skin
• commonly seen due to aging or corticosteroid therapy
• ie. steroid atrophy, scar

Question 29

What is a fistula?

Answer 29

• abnormal connection between hollow spaces
• “little tunnel”

Question 30

What is scaling?

Answer 30

• peeling, desquamation
• shedding of the outermost layer of the skin
• ie. psoriasis vulgaris, pityriasis, solar dermatitis

Question 31

What is lichenification?

Answer 31

• an increase in the skin lines, wrinkles and creases from chronic inflammation and rubbing
• ie. atopic dermatitis, chronic contact dermatitis

Question 32

What is a scar?

Answer 32

• aka cicatrix
• fibrous degeneration tissue due to wound repair in the skin, replacing normal skin after injury of the dermis and/or subcutis
• common after healing of ulcer, excoriation and fissure (but NOT after erosion)
• ie. surgical wound, keloid