Skin Infections Flashcards
When are skin conditions most common?
- In hot, humid climates
* Amongst, poorer populations
Examples of Skin infections (that we will cover)
- Staphococcus Aureus
- Treponema Pallidum
- Herpes Simplex
- Varicella Zoster
- Trichopytum
- Sarcoptes Scabei
Features of SA
Staphylococcus Aureus
o A gram +VE bacteria
o Commensal in approx. 30% of humans - colonisation in
• nose, axilla, groin
What skin infection manifestations can SA infection cause?
MOST COMMON bacterial cause of skin infection - includes
• impetigo
(infection of subcorneal layer of epidermis
• folliculitis
(infection of mouth of hair follicle)
• ecythma
(infection of full thickness of epidermis)
• boils
(abscess of hair follicle)
• carbuncles
(abscess of several adjacent hair follicles)
Onenote!!
What diseases can be caused by SA?
Via the production of TOXINS, SA can cause:
- Staphylococcal Scalded Skin Syndrome – Exfoliative toxin
- Toxic shock Syndrome – Toxic Shock Syndrome Toxin 1 (TSST-1)
- Food poisoning – Enterotoxin
- Necrotising soft tissue infections – Panton Valentine Leucocidin virulence factor
How can SA infections be treated and what are the symptoms?
Treated with ABS
• NO vaccine in place
BUT symptoms are
• bone, joint, lung infections
• sepsis
• severe pneumonia
Features of TP?
Treponema Pallidum
o A gram -VE spirochaete
o Cause of SYPHILIS
• an STI (increases transmission of HIV)
In regards to TP, explain the stages of Syphilis
Stages of Syphilis:
(1) Primary – painless ulcers (chancre) at site of inoculation (genital or oral)
(2) Secondary – disseminated infection with rash (maculopapular) and lymphadenopathy
(3) Latent – asymptomatic period (NO CLINICAL SIGNS)
(4) Tertiary – skin (gummatous skin lesions, bone lesions), neurological and vascular manifestations
Explain the transmission of syphilis and what it can cause
Can be VERTICALLY transmitted
• hence can cause COGENITAL SYPHILIS (miscarriage, still birth, prematurity, rashes etc.)
How can Syphilis be treated?
No vaccine available from infection
• BUT can be treated with ABs (e.g. penicillin)
What are the features of HSV?
Herpes Simplex
o Members of the HHV (human herpes virus) family
• these are DNA viruses
2 types:
• Type 1 - cause ORAL infections (HSV1)
• Type 2 - cause GENITAL infections (HSV2)
What are the pathogenesis of HSV?
Transmission by direct contact
• divides in neurones (latency is here)
Clinical features include:
• painful vesicular rash
• eczema herpeticum (defective barrier so susceptible to both SA & HSV)
• herpes encephalitis
Explain HHV-3
Varicella Zoster (chicken pox)
o Has LATENCY in the DORSAL ROOT GANGLIA
• hence will affect particular dermatome
• if reactivated = herpes zoster (shingles) which can cause non-cardiac chest pain & affect CNV (so face invovlement)
How can HHV-3 be treated?
Treatment:
o Mild = acyclovir
o If it involves CNV1 – IV acyclovir to
avoid blindness
o Post-infective neuralgia pain can be difficult to manage
General treatment of HSV?
NO vaccine available
Outbreak treated with ANTI-VIRAL medication
• e.g. Acyclovir
