Skin infection/infestation Flashcards
(24 cards)
What kind of infections affect the skin?
Bacterial -Staph and strep Viral -HPV, HSV, HZV Fungal -tinea, candida and yeasts
Note that infestations (e.g. scabies, cutaneous leishmaniasis) may also occur
What is cellulitis?
Spreading bacterial infection of the skin, involving the deep subcutaneous tissue
What is erysipelas?
Acute superficial form of cellulitis, involving the dermis and upper subcutaneous tissue
What are the causative organisms of cellulitis?
Strep Pyogenes
Staph Aureus
What are the risk factors for cellulitis?
Immunosuppression Wounds Leg ulcers Toeweb intertrigo Minor skin injury
How does cellulitis present?
Common in lower limbs Local signs of inflammation -swelling (tumour) -erythema (rubour) -warmth (calour) -pain (dolour) Systemically unwell with fever, malaise or rigours (esp with erysipelas) Erysipelas distinguished from cellulitis by well-defined, red raised border
How is cellulitis managed?
Abx e.g. flucloxacillin, benzylpenicillin Supportive care (rest, leg elevation, sterile dressings and analgesia)
What complications are associated with cellulitis?
Local necrosis
Abscess
Septicaemia
What is staphylococcal scalded skin syndrome (SSSS)?
Commonly seen in infancy/early childhood
Production of circulating epidermolytic toxin from phage group II, benzylpenicillin-resistant (coagulase positive) staphylococci
How does SSSS present?
Develops hours to days
May be worse over face, neck, axillae, groin
Scalded-skin appearance followed by large flaccid bullae
Perioral crusting typical
Intraepidermal blistering
Lesions very painful
Recovery usually 5-7d
How is SSSS managed?
Abx (e.g. systemic penicillinase-resistant penicillin, fusidic acid, erythromycin or appropriate cephalosporin)
Analgesia
What are superficial fungal infections?
Common and mild infection of superficial layers of skin, nails and hair
Can be severe in immunocompromised populations
What causes superficial fungal infection?
Dermatophytes -tinea/ringworm Yeasts -candidiasis -malassezia Moulds -aspergillus
How do superficial fungal infections generally present?
Varies with site of infection
Usually unilateral and itchy
How does tinea corporis present?
Infection of trunk and limbs
Itchy, circular or annular lesions with clearly defined, raised and scaly edge typical
How does tinea cruris present?
Infection of groin and natal cleft
Very itchy, similar to tinea corporis
How does tinea pedis present?
Athlete’s foot
Moist scaling and fissuring in toewebs, spreading to sole and dorsum of foot
How does tinea manuum present?
Infection of hand
Scaling and dryness in palmar creases
How does tinea capitis present?
Scalp ringworm
Patches of broken hair, scaling and inflammation
How does tinea unguium present?
Infection of nail
Yellow discolouration, thickened, crumbly nail
How does tinea incognito present?
Inappropriate treatment of tinea infection with topical/systemic corticosteroids
Ill-defined and less scaly lesions
How does candidiasis present?
Candidal skin infection
White plaques on mucosal areas, erythema with satellite lesions in flexures
How does pityriasis/tinea versicolour present?
Infection with Malassezia furfur
Scaly pale brown patches on upper trunk that fail to tan on sun exposure, usually asymptomatic
How are superficial fungal infections managed?
Establish diagnosis with skin scrapings, hair or nail clippings (for dermatophytes); skin swabs (for yeasts)
General measures
-treat precipitants (underlying immunosuppressive condition, moist environments)
Topical antifungals e.g. terbinafine cream
Oral antifungals e.g. itraconazole for severe widespread or nail infections
Avoid topical steroids (tinea incognito)
