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3. DERMATOLOGY > Infections > Flashcards

Flashcards in Infections Deck (6)
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What is erysipelas

Acute superficial form of cellulitis, involves dermis and upper subcutaneous tissues

Distinguished from cellulitis by well-defined red raised border


What is cellulitis?

Cause, presentation, treatment, complications

Spreading bacterial infection of skin, involves deep subcutaneous tissue

Causes: strep pyogenes and staph aureus

Risk factors: immunosuppression, wounds, leg ulcers, toeweb intertrigo, minor skin injury

Most common lower limbs, local signs of inflammation, may be associated with lymphangitis. Systemically unwell with fever, malaise or rigors, particularly with erysipelas.

Tx: flucloxacillin or benzylpenicillin, supportive care - leg elevation sterile dressing and analgesia

Complications: local necrosis, abscess and septicaemia


What is staphylococcal scalded skin syndrome?

Include Tx

Commonly seen in infancy and early childhood - production of circulating epidermolytic toxin from phage group II, benzylpenicillin-resistant (coagulase positive) staphylococci

Develops within few hours - few days, may be worse over face, neck, axillae or groins. Scald-like skin appearance is followed by large flaccid bulla.

Perioral crusting is typical, intraepidermal blistering, lesions are very painful, sometimes the eruption is more localised, recovery within 5- 7days

Treatment: Abx e.g. systemic penicillinase-resistant penicillin, fusidic acid, erythromycin or appropriate cephalosporin. analgesia


What are the main superficial fungal infections?

Common and mild infection of superficial layers of skin, nails and hair - can be severe in immunocompromised individuals

Dermatophytes (tinea / ringworm)
Yeasts (candidiasis / malassezia)
Moulds (e.g. aspergillus)


Types of tinea?

Tinea corporis: usually trunk and limbs: itchy, circular or annular lesions with clearly defined, raised and scaly edge

Tinea cruris: groin and nasal cleft, similar, very itchy

Tinea pedis: athlete's foot, moist scaling and fissuring in toewebs, spreading to sole and dorsal aspect of foot

Tinea manuum: hands - scaling and dryness in palmar creases

Tinea capitis: scalp ringworm - patches of broken hair, scaling and inflammation

Tinea unguium: nail infection - yellow discolouration, thickened and crumbly

Tinea incognito: ill-defined, less scaly lesions - inappropriate Tx of tinea infection with topical or systemic corticosteroids

Tinea versicolor (pityriasis): Malassezia fufur (yeast) infection, scaly pale brown patches on upper trunk, fail to tan, usually asymptomatic

Also - candidiasis - white plaques on mucosal areas, erythema with satellite lesions in flexures


Management of fungal infections

Correct Dx: skin scapings, hair/nail clippings (dermatophytes) or skin swabs (yeasts)

Treat underlying immunosuppressive condition, moist environment

Topical antifungals e.g. terbinafine cream
Oral antifungal e.g. itraconazole for severe / widespread or nail infection

Avoid topical steroids, can lead to tinea incognito