Skin Disorders - Infections

Question 1

Verruca vulgaris

Answer 1

• common wart
• Histology: epidermal hyperplasia with viral change (koilocytes - virus - infected keratinocytes in epidermis)
• Principles of Therapy: creo with liquid nitrogen, topical salicylic acid

Question 2

Condyloma accuminatum

Answer 2

• genital, STD, HPV 6, 11 most common, not associated with increased cancer risk
• HPV 16, 18 associated with carcinoma
• Histology: epidermal hyperplasia with viral change (koilocytes - virus - infected keratinocytes in epidermis)
• Principles of Therapy: creo with liquid nitrogen, topical salicylic acid

Question 3

Molluscum contagiosum

Answer 3

• 2-3 mm papules, keratitis, umbilicales center
• diffuse in children, STI in adults
• Histology: molluscum bodies, cytoplasmic inclusions, largest known DNA pox virus, proliferates in cytoplasm
• Principles of Therapy: children may require no treatment for sparse lesions, adults - cryo, cantheridin in children, chlorhexadine soap to prevent spread

Question 4

Herpes

Answer 4

• Simplex - lips = Type I genital = Type II, vesicles tend to be clustered on erythematous base, recurrent, can cross placenta
• Varicella: Chicken Pox, “dewdrop on a rose petal” vesicle on erythematous base, lesions in various stages of development, can cross placenta
• Zoster: reactivation of Varicella, dermatomal, pain which persists after lesions resolve (PHN), can cross placenta
• Histology: viral nuclear change, (ground glass cytoplasm and marginación of chromatin) and epithelial giant cells
• Principles of Therapy: antivirals, isolation, varicella vaccine for children, zoster vaccine for adults >60

Question 5

Impetigo

Answer 5

• most common in children
• Staph and Strep bacteria
• honey colored crusting
• Histology:subcorneal neutrophils and bacterial colonies
• Principles of Therapy: topical mupirocin, systemic antibiotics if severe

Question 6

Abscess

Answer 6

• cutaneous abscess is a collection of pus within dermis
• Histology: neutrophils within a structureless space, may be bounded by a fibrous capsule
• Principles of Therapy: lance and drain

Question 7

Follicultis

Answer 7

• inflammation of hair follicle, usually due to infection
• pustules, furuncles, carbuncles, abscesses
• Staph and STrep bacteria
• MRSA sometimes present
• Histology: neutrophils collections within hair follicle or abscess
• Principle of Therapy: topical mupirocin, systemic antibiotics if severe, abscess lanced and drained and cultured

Question 8

Celulitis/Erysipelas/Necrotizing fascitis

Answer 8

• broad erythema, edema, heat, tenderness
• Histology: edema with neutrophils extending through dermis
• erysipelas is cellulitis involving the superficial dermis - intensely erythematous, raised indurated plaques with sharp border, face and legs
• Staph and Strep bacteria
• severe can lead to lymphangitis
• severe cases —-> necrotizing fasciitis: Strep A, expanding erythematous plaques, progresses rapidly, LIFE THREATENING
• Principles of Therapy: systemic antibiotics, hospitalization, surgical intervention

Question 9

Syphilis

Answer 9

•spirochete bacterium, treponema pallium
•STI
•crosses placenta
•three phases
Primary Chancre: single, ulcerated, painless 10 - 90 days after exposure, clears spontaneously in 4-8 weeks
Secondary Syphilis: widespread rash, recurs over a period of 2 years
Tertiary Syphilis: 3- 10 years after infection, gummas, granulomas
•detected with Rapid Plasma Reagin (RPR) and treponemal test
•Treatment: antibiotics

Question 10

Pityriasis (tinea) versicolor

Answer 10

• lighter or darker spots with subtle scale on upper torso
• malassezia furfur yeasts are normal colonists on skin, but shift into hyphal
• secrete Amelia acid which inhibits melanin production
• Prevention: zinc pyrithione or selenium sílfide
• Treatment: topical clotrimazole and other antifungals

Question 11

Onychomycosis

Answer 11

•fungal infection

Question 12

Lyme Disease

Answer 12

• borrelia burgdorferi spirochete
• tick
• antibiotics

Question 13

Rocky Mountain Spotted Fever

Answer 13

• Rickettsia rickettsia
• ticks
• macules on wrists and ankles progresses to rash on trunk and extremities
• Treatment: antibiotics

Question 14

Scabies

Answer 14

• arthropod

* Therapy: permethrin, ivermectin and previously with lindane which can be neurotoxic