COMMON SKIN INFECTIONS

DR T.T MOKWENA DERMATOLOGY DEPARTMENT Skin Infections

Classification of 1. Primary  – Superficial – Deep * Folliculitis of leg * Furuncle * * Sycosis Barbae

Skin Infections

• / • SSSS • TSS

2. Secondary Secondary infection of preexisting dermatoses eg. Atopic dermatitis, Scabies

Causative Organisms • Bacterial

• Fungal

• Viral

• Parasitic Bacterial Skin Infections

• Very common • Range from annoying to deadly infections • Mostly caused by Staph aureus and Strep Bacterial Skin Infections

• Folliculitis – Infection of hair follicle

– Usually heals without scarring

– Caused by Staph aureus

– Tx: Warm saline compresses. If does not resolve spontaneously in 1- 2 weeks, topical mupirocin. Oral cloxacillin ( very rare)

Young male presenting with pruritic erythematous macules that progressed to papules and pustules

folliculitis

Staph Skin Infections

• Furuncle/

– Infection of pilosebaceous unit (hair follicle and surrounding tissue)

– Usually must drain before they heal – takes less than 2 wks

– Complicated – over middle of face/ spine or with fever

Staph Skin Infections

• Carbuncle

– Several furuncles that are densly packed together

– Common in diabetics

– Tx : severe cases, first I&D

– Oral antibiotics (cloxacillin), or cephalexin if fever

Furuncle Carbuncle Staphylococcal scalded skin sydrome (SSSS)

• Exotoxin of staph (Phage Group II)

• Acantholysis

• Occult staph. upper respiratory tract infection or purulent conjunctivitis

• Infants and children

• Tender red skin

Acute

– Infection of lateral and posterior nail fold – Most common pathogen Staph aureus – Results from nail biting, finger sucking, excessive manicuring or penetrating trauma – Conservative tx: Warm soaks/ oral antibiotics ( clindamycin, augmentin) – If or fluctuance is present, spontaneous drainage / incision and drainage. – I & D: blade is directed away from the nail plate

Acute Paronychia Impetigo

• Non-bullous – principal pathogen is Staph aureus

• Group A beta hemolytic strep minority of cases

• Bullous form is nearly caused by Staph aureus (common in infants and children < 2yrs)

• Honey crusted lesions/large vesicles Impetigo (cont…) • Tx: topical mupirocin as effective as oral antibiotics – Oral antibiotics for nonlocalized cases - cloxacillin, 1st gen cephalosporin, augmentin. – Macrolides not adequate given increasing resistance. • Complication: Strep glomerulonephritis

• Nasal carriage, source for reccurrence, tx - topical mupirocin

• Very contagious, appropriate hygiene for prevention

Impetigo contagiosa (Non bullous form))

Impetigo (Bullous form) Cellulitis

• Painful erythematous infection of dermis and subcut tissue

• Beta hemolytic strep , may be combined with staph (MRSA on the rise)

Commonly occurs near skin breaks, such as trauma, surgical wounds, tinea infections( in diabetics) • Tx: 1st gen cephalosporins, augmentin – Limited disease(oral treatment), extensive disease requires parenteral treatment

– I&D if fluctuant

• May turn into necrotizing fascitis – medical emergency

Cellulitis MRSA Infections

• Community acquired – MRSA – in children in daycare – Athletes – Military recruits • Healthcare associated –MRSA • Resistant to multiple antibiotics, send for C&S • Tx : CA- MRSA :Clindamycin, Doxycycline, Bactrim, Vancomycin HA-MRSA : Vanc, Linezolid • Recurrence very common • Prevention: personal hygiene is the key – Wash hands !! – Do not share personal items – Cover all open wounds

• Results in pink patches to brown scales, may be pruritic. Lichenification and hyperpigmentation common • Caused by minutissimum • Commonly found in intertriginous areas/ toe webs • Prevalent among diabetics, obese, and in warm climates, worsened by wearing occlusive clothing • DDx: tinea, acanthosis • Dx: KOH neg, Wood’s lamp : coral pink fluorescence • Tx: oral erythromycin 1-2 weeks • Abx soap to prevent recc Erythrasma

Common Viral Skin Infections Viral warts/Condylomas/Squamous cell papillomas/ Verrucae

• Small, rough tumor w/ cauliflower surface or solid blister

• Hands, feet, genital areas

• Caused by HPV – 6 & 11 serotypes • Tx : topical irritants – Salicylic acid, podophyllin, cantharidin,trichloroacetic acid – Destructive methods: cryo, electro, laser excision/curretage

• Prevention: Gardasil vaccine Common wart Plantar wart Herpes simplex infections

• Mucocutaneous: prodrome followed by grouped tensed vesicles over an erythematous base • Herpetic gingivostomatitis in children • H.labialis/cold sores/ – caused by HSV 1

• Genital herpes : usually caused by HSV2 • Dx: clinical, if atypical lesion: Tzanck , PCR, Culture, serology • Tx: acyclovir, valacyclovir: reduce viral shedding and duration of sx during primary infection • Recc infection: tx with beginning of the first symptom • Frequent eruptions( >6/yr) should receive daily supressive tx • Herpetic whitlow, no I & D ( risk of bact superinfection or systemic spread.

Herpes labialis Herpetic gingivostomatitis Herpetic whitlow Molluscum contagiousm

• Caused by pox virus, MCV

• Flesh colored, dome shaped,pearly w/ typical central umbilication

• Common in children

• Autoinoculation spreads to neighboring areas

• Tx: self resolving sometimes or cryotherapy( using liquid nitrogen) Molluscum contagiosum Hand foot and mouth disease

• Caused by Coxsackie A16, member of enterovirus family

• Tender blisters, fever, sore throat, ulcers in throat, loss of appetite

• Children under 10 yrs of age

• Spread by person to person

• Outbreaks in summer and early fall

• Symptomatic tx: prevent dehydration Hand Foot And Mouth Disease

CLASSIFICATION OF CUTANEOUS

TRUE CUTANEOUS TUBERCULOSIS TUBERCULIDES

EXOGENOUS ENDOGENOUS HEMATOGENOUS

• Tuberculosis • • Acute miliary TB • Papulonecrotic tuberculide

• Warty TB (verrucosa • Peri-orifial • • Lichen cutis) tuberculosis scrofulosorum

• Lupus vulgaris • Tuberculous gumma • of Bazin

• Nodular phlebitic tuberculid