skin infections

Bacterial skin infections

• impetigo

• Folliculitus

• Furuncles boils

• Carbuncles

• Erysipelas

• Cellulitis

• Necrotising fasciitis

Furuncles or boils

• infection spread in the dermis attracting neutrophils → pus

• Pus is sealed by an abscess

Carbuncles

• cluster of connected Furuncles or one Furuncles not walled off

• Larger area of inflammation, deeper in the dermis or hypodermics

Streptococcal skin infections

• well defined raised and shiny bright red rash

• Sharp borders often with raised margins

• Common on face

Cellulitis

• infections in the deeper dermis- subcutaneous tissue

Necrotising fasciitis

• severe infection in subcutaneous tissue and below

Superficial bacterial skin infection- treatment option

• good hygiene

• Superficial localised impetigo

• Topical hydrogen peroxide

Bacterial skin infections

• bullous impetigo

• Mild deeper infections

• Oral antibiotics

MRSA

• S. aureus strains resistant resistant to multiple B lactam antibiotics

• Display higher MIC values to B lactam compared to MSSA

HPV

• cervical screening smear test to detect the HPV genotype and precancerous cells

• HPV vaccines are available to prevent infections from high risk genotypes

Cutaneous warts

• benign skin growths from cutaneous HPV

• Grainy slightly raised lesions

• Common warts plantar warts or verruca

• Self limiting but may cause discomfort

Cutaneous wart formation

• HPVs enter the broke skin

• Infects basal keratinocytes → and establish persistent infection

• Their genome encode viral proteins that promote continuous cell proliferation

• Thickened epidermis and keratinocytes do not differentiate properly

Warts treatment option

• topical salicylic acid

• Cryotherapy using liquid nitrogen

• Ablative therapy

Herpes virus infections and reactivation

• primary infections → cold sores

  • Itching fluid filled vesciles

• HSV-1 establishes latency in the tri germinal nerve ganglia

• Reactivation: triggered by stress illness, or immune suppression

• Recurrent cold sores

Antiviral chemotherapy for herpesvirus infections

• acyclovir 5% cream

• Oral acyclovir prodrugs

Fungal skin infections

• superficial dermatomycoses

  • Involves epidermis stratus

  • Affecting trunk, feet, scalp

• Subcutaneous mycoses

  • Involves dermis and subcutaneous tissue

Dermatomycoses

• skin microbiota equilibrium

• Imbalance favours fungal overgrowth

• Transmission: direct contact or sharing contaminated objects

Treatment dermatomycoses

• topical OTC antifungal: first line for mild cases

• Imidazole cream