Skin Infections + Infestations Flashcards
What are the most common bacterial skin infections?
20% of outpatient derm visits
- Impetigo
- Folliculitis
- Cellulitis
- Erysipela
- Syphilis
- Leprosy
- Rickettsial diseases
What is the most common ( and v contagious) bacterial infection in children?
Impetigo
Predisposing factors for impetigo?
Warm temp, high humidity
Poor hygiene
Skin trauma
What bacteria most commonly cause impetigo?
Staph aureus (to a lesser degree Strep pyogenes)
What is the clinical presentation of impetigo?
Macule rapidly becomes vesicle then pustule then erosion with ‘honey-coloured’ yellow crust and rapid extension to surrounding skin
How is impetigo treated?
Local wound care
Topical abx
What is folliculitis?
Infection of the hair follicule
What bacteria most commonly causes folliculitis?
Staph aureus
Predisposing features of folliculitis?
Occlusion Maceration + hyperhydration Shaving/waxing Topical corticosteriods Diabetes
What areas does folliculitis affect?
Face, chest, back, axillae, buttocks
How to identify causative organisms?
Bacterial cultures
Treatment for folliculitis?
Antibacterial washes
Antibacterial ointments
What is erysipelas?
Infection of the dermis w lymphatic involvement, most commonly caused by group A strep
What groups of people does erysipelas affect?
V young
Elderly
Debilitated
Those with lymphoedema/chronic cutaneous ulcers
Clinical presentation of erysipelas?
Erythema with well defined margins
Affected skin is hot, tense, indurated
Face, lower extremities
May have fever, chills, malaise, nausea
Diagnosis is clinical, but what could lab results show that contribute?
Elevated leukocyte count w left shift
Treatment for erysipelas?
10-14 day course of penicillin
What is cellulitis?
Infection of the deep dermis and subcutaneous tissue caused most commonly by Strep pyogenes or Staph aureus
Predisposing factors for cellulitis?
Lymphoedema Alcoholism Diabetes mellitus IV drug abuse Peripheral vascular disease
How does cellulitis present? (4 words for affected area)
Affected area = rubor, calor, dolor, tumor
Lesion has ill-defined, non-palpable borders
Children: H+N; adults: extremities
How is cellulitis treated?
Abx (depending on systemic symptoms and gravity, also risk factors)
What is syphilis?
Complex sexually transmitted infection
What bacteria causes syphilis?
Treponema pallidum
What is the time frame of presentation of syphilis?
Episodes of active disease occur, followed by latent periods
What is the danger if syphilis is left undiagnosed?
Tertiary syphilis can develop years later and cause a variety of problems affecting the brain, eyes, heart and bones
How does primary syphilis present?
Painless small single ulcer where he infection has entered (around genitals, anus or mouth) and may go unnoticed (known as chancre)
Heals in 4-8 weeks w/o treatment and 1-2 weeks w treatment
When does secondary syphilis occur?
3 weeks to 3 months after 1st stage
How does secondary syphilis present?
Widespread skin rash
May be subtle or appear as rough, red/reddish brown papules/patches
Typically on trunk/palms + soles
Not itchy
How does tertiary syphilis present?
Solitary granulomatous lesions (gummas) may be on skin, in mouth and throat/occur in bones
Brain, spinal cord, heart, liver, eyes may be affected
What tests can be done for syphilis?
Non-specific non-treponemal tests (VDRL)
Specific anti-treponemal antibody tests (TTPA)
Treatment of syphilis?
Penicillin by injection depending on stage of disease