Lesions and Pathogenesis for Skin Infections

abcess

localized collection of pus

carbuncle

cluster of interconnected furuncles

furuncle (boil)

a painful, pus filled bump under the skin

macule

a flat discolored spot on the skin

papule

a small raised bump on the skin

pustule

a raised lesion filled with pus

purulent

containing or producing pus

pyoderma

a bacterial skin infection characterized by pus formation

ulcer

a sore that develops on the skin or mucous membrane

vesicle

a small fluid filled blister

rubeola virus

virus that causes measles

symptoms include fever, rash

transmitted via respiratory droplets

no vaccine

rubella virus

virus that causes rubella

symptoms include rash, fever

transmitted via respiratory droplets

vaccine available (attenuated)

VZV

virus that causes chickenpox (primary) and shingles (reactivation after latency)

symptoms include rash, itching

vaccine available (attenuated)

borrelia burgdoferi

gram negative spirochete bacteria that causes lyme disease

symptoms include rash, fever

transmitted by ticks » zoonotic

no vaccine

clostridium tetani

gram positive bacilli that causes tetanus

symptoms include muscle spasms

transmitted through wounds

vaccine available (toxoid)

clostridium perfringes

gram positive bacilli that causes gas gangrene

symptoms include muscle spasms

transmitted through wounds

no vaccine

epidermophyton, microsporum, trichophyton

molds that cause ringworm (tinea)

symptoms include itchy rash

transmitted through skin-skin contact

no vaccine

features of herpes viruses

• enveloped

• double stranded DNA

• establish latency in host cells » recurrent infections

primary infection site for VZV

respiratory tract

latency area for VZV

sensory ganglia

spirochetes characteristics

• thin

• spiral shaped bafcteria

• motile with axial filaments

  • associated with lyme disease

deer tick lifecycle

1. Larva (feed on infected rodents and deer)

2. Nymph

3. Adult Stage

vector of borrelia burgdorferi

deer tick

reservoir of borrelia burgdoferi

rodents and deer

accidental host of borrelia burgdoferi

humans

phases of lyme disease

1. Early Localized - erythema migrans, rash, flu like symptoms

2. Early Disseminated - neurological symptoms and heart issues

3. Late Stage - chronic arthritis, neurological problems

primary virulence factor of dermatophytes

keritanase » allows invasion of keratinized tissues

clostridium diseases produce _____

endospores » allows survival in harsh conditions and infections in favorable ones

where clostridium thrives

anaerobic, ischemic environments

tetanospasmin

causes spasms by blocking neurotransmitter release

alpha toxin

damages cell membranes, leading to tissue necrosis

theta toxin

increases vascular permeability and contributes to tissue damage