Common Bacterial Infections

Question 1

What are the 2 types of impetigo & their causative agents?

Answer 1

Non-bullous impetigo = S aureus, S pyogenes, S agalactiae (pustules around the face & nares)

Bullous impetigo = S aureus exfoliatin toxins A & B (- Nikolsky sign)

Question 2

What are S/Sx of Impetigo?

Answer 2

Regional lymphadneopathy
Honey-colored crusts on the anterior nares (S aureus)

Question 3

What is a potential dermatologic emergency caused by impetigo?

Answer 3

Staphylococcal scalded skin syndrome

Question 4

What are the diff drugs used for Bullous impetigo?

Answer 4

Dicloxacillin = DOC
Erythromycin = if allergic to dicloxacillin, less drug reactions
Others: Clindamycin, Azithromycin, Cephalexin

Question 5

What is the clin presentation of non-bullous impetigo in localized infections?

Answer 5

No >10 localized lesions & not exceeding 100cm2 in total area (size of a sliced bread)

Question 6

What is the tx for localized infection of non-bullous impetigo?

Answer 6

Mupirocin or Fusidic acid ointment

Question 7

What acaues Ecthyma & its clin presesntation?

Answer 7

S. Aureus & Group A Strep

Impetigo beyond the epidermis to upper part of the dermis

Question 8

What are the 2 tyes of Folliculitis & its apprance?

Answer 8

Acute Superficial Folliculitis = seen in any hair-bearing part of the skin

Staphylococcal folliculitis = Sycosis barbae & lupoid sycosis

Question 9

What happens if folliculitis develops into a deeper and neglected form?

Answer 9

Furuncles & Carbuncles

Question 10

What are other risk factors for developoment of Furuncles & Carbuncles?

Answer 10

Obesity
Blood dyscrasias
Defect in neutrophil function

Question 11

What are the diff between Furuncle & Carbuncle?

Answer 11

Furuncle = hard, tender, folliculocentric nodule, hair-bearing area

Carbuncle = multiple pustules that have coalesced on surface

Question 12

What are the tx for Carbuncles & Furuncles?

Answer 12

Dicloxacillin & Amoxiclav
- maximal dosage of antibiotics if seen in dangerous areas (T zone & nasal area of the face)

Question 13

What are the causes of Erysipelas?

Answer 13

Group A Strep
Group B, C, G strep
S aureus

Question 14

What are the clinical manifestations of Erysipelas?

Answer 14

Leg & face
Painful, superifical, brigh red edematou, indurated plaque with advanced raising border

Question 15

What are the tx for Erysipelas?

Answer 15

Penicillin V
If allergic to penicillin = azithromycin or erythromycin

Question 16

What are the causative agents of acute cellulitis?

Answer 16

Group A Strep
S aureus

Question 17

What are the clinical manifestations of Acute cellulitis?

Answer 17

Severe, extremely painful
Deeper dermis & SQ fat
Not raised or well-define

Question 18

What is the causative agent of Pitted Keratolysis?

Answer 18

Micrococcus sedentarius

Question 19

Whta are the clinical manifestations of Pitted Keratolysis & its course?

Answer 19

CM: extremely smelly, punched out pits and macerations on plantar surface of the feet

Course: softened Stratum corneum

Question 20

What is the CA of Erythrasma?

Answer 20

Corynebacterium minutissimum

Question 21

What are the clinical manifestations of Erythrasma?

Answer 21

Hyperkeratotic white macerated plaque
- webbed spaces of the feet & intertriginous areas (groin & axillae)

Question 22

What is the lab test for Erythrasma and characteristic feature?

Answer 22

Wood’s light lamp: (+) coral ref fluorescence

Question 23

What are the distinct features of diff stages of syphilis?

Answer 23

Primary syphilis = 1 or more chancres (hard chancre/painlesss); Regional lymphadenopathy

Secondary syphilis = localized/diffused mucocutaneous lesions; Biet collarette (white scaly ring on the surface of lesions); Condylomata lata

Latent syphilis = asymptomatic

Tertiary syphilis = gumma & saffle-nose deformity

Question 24

What are the tx options for Syphilis?

Answer 24

Penicillin G or Benzathine (All stages)

Doxycycline = not pregnany & w/o neurosyphillis

Desensitization + Penicillin tx = pregnant women w penicllin allergy

Question 25

How can you say that tx for syphilis is succesfful?

Answer 25

If there is a fourfold (2-diluation) decline in nontreopmental test tilter

Follow-up at 6 month intervals until a fourfold decline is seen except HIV-infecter persons = 3,6,9, 12, 24 recomm

Congenital syphilis = follow up every 2-3 months