Infections Flashcards
What are tinea?
Dermatophyte ringworm fungal infection
Invade and grow in dead keratin
Round scaly itchy lesion whose edge is more inflamed than its centre
Well defined annular erythematous lesions with pustules and papules
Called tine followed by part affected
tinea pedis - athlete’s foot
tinea captitis - scalp
tinea corporis - body
What is management for skin tinea?
Topical antifungal e.g.terbinafine or imidazole creams
Oral fluconazole
What is management for scalp tinea?
Treat empirically with oral antifungals griseofulvin or terbinafine + ketoconazole shampoo until cultures are known
Trichophyton tonsurans responds to terbinafine
Girseofulvin for Microsporum canis infection
What is molluscus contagiousum?
Common skin infection caused by molluscum contagiosum virus (MCV), a member of the Poxviridae family.
Transmission occurs by close personal contact or indirectly via contaminated surfaces.
Majority of cases occur in children
What is the typical appearance of molluscs contagiosum?
Pink papules with a central umbilication up to 5mm in diameter
Lesions appear in clusters in areas anywhere on the body (except the palm of hand and soles of feet)
Lesions commonly seen on trunk and in flexures
In adults, sexual contact may lead to lesions on genitalia, pubis, tights, lower abdomen, oral mucosa, eyelids
What advice in molluscs contagious?
Reassure that it is self-limiting
Spontaneous resolution within 18m
Lesions are contagious, avoid sharing towels, clothing and baths with uninfected
Encourage not to scratch
Exclusion from school/pool/gym not necessary
What treatment in molluscum contagiosum? When to refer?
TREatemnt is often not recommednted
Gentle cryotherapy
Squeezing or piercing lesions following a bath
IF itching is problem - emollient and mild topical corticosteroid
Infection - topical antibiotic (fuscidic acid)
Refer if
HIV +
Eyelid margin or ocular lesion and red eye
Anogenial lesions to STI clinic
What is onychomycosis? Features?
Fungal nail infection
May be caused by:
Dermatophyes - Trichophyton rubrum
Yeasts - candida
RF:
DM
Increasing age
Unsightly nails
Thickened rough opaque nails
Investigations and management of onychomycosis?
Nail clippings
Scrapings of affected nail
Culture
Dermatophyte infection: Oral terbinafine first line Oral intraconazole 6w-3m for fingernail 3m-6m for toenail
Candida - topical antifungals (e.g. amorolfine)
More severe - oral intraconazole
What is pityriasis versicolour? Organism? Features?
Superficial cutaneous fungal infection caused by Malassezia furfur
Mostly affects trunk
Patches of hypo pigmented, pink or brown skin
Scale is common
Mild pruritus
What is management of pityriasis versicolour?
Topical antifungal - ketoconazole shampoo
Mx for athletes foot?
Topical imidazole/miconazole 4 weeks
if this does not work, oral antifungal - terbinafine
Combination with topical corticosteroids if severely inflamed
What is impetigo? Causes?
Impetigo is a superficial bacterial skin infection usually caused by either Staphylcoccus aureus or Streptococcus pyogenes. It can be a primary infection or a complication of an existing skin condition such as eczema (in this case), scabies or insect bites
Who does impetigo occur in? When? Where?
Impetigo is common in children, particularly during warm weather.
The infection can develop anywhere on the body but lesions tend to occur on the face, flexures and limbs not covered by clothing.
How does impetigo spread?
Spread is by direct contact with discharges from the scabs of an infected person. The bacteria invade skin through minor abrasions and then spread to other sites by scratching. Infection is spread mainly by the hands, but indirect spread via toys, clothing, equipment and the environment may occur. The incubation period is between 4 to 10 days.
