Dermatology Flashcards
What are the causes of nappy rash?
- Irritant dermatitis (inflammation of the skin due to contact with urine and faeces)
- Candida infection
How can you differentiate between nappy rash caused by irritant dermatitis and candida infection clinically?
Irritant dermatitis:
- Rash spares the flexures
Candida infection:
- Rash includes the flexures
Describe the management of nappy rash due to irritant dermatitis
Mainly conservative:
- Leave nappy off as much as possible
- Change nappy often
Medical:
- Use a thin layer of barrier cream/ointment before putting on each nappy, e.g. metanium
- Steroid cream/ointment, e.g. hydrocortisone
Describe the management of nappy rash caused by candida infection
Topical antifungal treatment: an imidazole cream (e.g. clotrimazole, miconazole)
When does infantile seborrhoeic dermatitis present?
Usually in the first few weeks of life
Describe the clinical presentation of infantile seborrhoeic dermatitis
- Initially appears as erythematous, scaly rash on the scalp
- Then forms a thick yellow adherent layer (‘cradle cap’)
- Rash may spread to the face, behind the ears, flexural surfaces (e.g. axillae) and nappy area
- Does not bother baby
Describe the management of infantile seborrhoeic dermatitis
Mild cases (conservative management):
- Parental reassurance, advise that rash will clear on its own
- Can use emollient/baby shampoo and gentle brushing to soften and loosen the scales
Moderate/severe cases (i.e. widespread involvement)
- Imidazole cream (e.g. clotrimazole, miconazole)
Describe the aetiology of molloscum contagoisum
Poxvirus
Describe the skin lesions found in molloscum contagiosum
- Small, skin-coloured pearly papules with central umbilication
- Usually widespread
Describe the prognosis of molloscum contagiosum
Is it contagious?
- Self-limiting
- Treatment not usually recommended
- It is very contagious (spread directly through close personal contact, and indirectly through towels, flannels etc.)
What are the clinical features of eczema?
- Dry, red, itchy patches of skin
- Infants: face and trunk
- Younger children: extensor surfaces
- Older children a more typical distribution is seen, with flexor surfaces affected and the creases of the face and neck
Describe the management of eczema (maintenance and flares)
Maintenance management:
- Emollient, emollient, emollient!
Flares:
- Emollient
- Topical steroids (use lowest potency required for shortest time required)
- Dressings/bandages
What are the potential complications of eczema?
- Eczema herpeticum (viral infection)
- Secondary bacterial infection
Describe the aetiology of eczema herpeticum
Viral skin infection caused by HSV1
What are the clinical features of eczema herpeticum?
- Itchy, red rash (eczema) has become vesicular and painful
- Systemic symptoms = fever, lethargy, reduced oral intake
Describe the management of eczema herpeticum
- Potentially life-threatening emergency
- Admission and IV aciclovir
Describe the aetiology and pathophysiology of secondary bacterial infection in eczema
- Staphylococcus aureus
- Breakdown in skin’s protective layer allows an entry point
What are the clinical features of secondary bacterial infection in eczema?
Worsening in eczema (increased redness, oozing, crusting of the skin)
Describe the management of secondary bacterial infection in eczema
Flucloxacillin (oral or IV, depending on severity)
Which organisms cause impetigo?
Staphylococcal or streptococcal infection, e.g. Staphylococcus aureus
What are the clinical features of impetigo?
- Lesions are usually on the face, around the nose and mouth
- Initially erythematous macules
- Then form honey-coloured crusts
Describe the management of impetigo
Are children allowed to go to school?
- 1st line: topical hydrogen peroxide; 2nd line: topical fusidic acid
- Severe cases may require oral antibiotics, e.g. flucloxacillin
- Highly contagious - children MUST NOT go to nursery or school until the lesions are healed, dry and crusted over
Which organisms cause periorbital cellulitis?
Staphylococcal or streptococcal infections, e.g. Staphylococcus aureus
What are the clinical features of periorbital cellulitis?
- Fever
- Erythema, tenderness and oedema of the eyelid and skin surrounding the eyelid
- Almost always unilateral
Give some risk factors for periorbital cellulitis
- Preceding paranasal sinus infection
- Preceding dental abscess
Describe the management of periorbital cellulitis
Immediate IV antibiotics (3rd generation cephalosporin) e.g. ceftriaxone, to prevent posterior spread of infection causing orbital cellulitis
Which organism that causes scalded skin syndrome?
Staphylococcus aureus (SSSS - Staphylococcal Scalded Skin Syndrome)
Describe the pathophysiology of scalded skin syndrome
Staphylococcus aureus produces a toxin which causes the epidermis to blister and peel
What are the clinical features of scalded skin syndrome?
- Fever
- Painful, blistering, peeling skin
Describe the management of scalded skin syndrome
- IV flucloxacillin
- Analgesia
- Fluids
What is ringworm? What are the clinical features?
How is ringworm classified?
- Fungal infection
- Itchy, CIRCULAR, erythematous, scaly rash
- Well-demarcated
Classified according to location:
- Tinea capitis = ringworm of the scalp
- Tinea pedis = ringworm of the foot (athlete’s foot)
- Tinea cruris = ringworm of the groin
- Tinea corporis = ringworm on the body
Describe the management of ringworm
- Topical imidazole creams (e.g. clotrimazole, miconazole)
- Severe cases: add oral antifungal (e.g. fluconazole)
Describe the aetiology and pathophsyiology of scabies
Caused by mites (Sarcoptes scabiei) which burrow under the skin and lay eggs
What are the clinical features of scabies
- Incredibly itchy
- Small red spots
- Classical location: starts between fingerwebs then becomes widespread
Describe the management of scabies
Treat the patient and all household members/close contacts with a topical insecticide (5% permethrin cream)
Wash everything!!!
Describe the aetiology of erythema multiforme
Triggered by infection (most commonly HSV) or certain drugs…
Drugs:
- Antibiotics, e.g. penicillin
- NSAIDs, e.g. ibuprofen
- Anticonvulsants, e.g. phenytoin, carbamazepine
What are the clinical features of erythema multiforme?
- Widespread itchy, erythematous rash
- ‘Bullseye’ or ‘target’ lesions
Describe the management of erythema multiforme
- Withdraw offending medication if applicable
- Usually self-resolving
Describe the pathophysiology of psoriasis
Autoimmune + environmental trigger
What are the clinical features of psoriasis?
- Recurrent episodes of dry, flaky, scaly, erythematous patches over extensor surfaces (knees, elbows) and scalp
- Guttate psoriasis is a common presentation in children - often follows a streptococcal or viral sore throat/ear infection
Describe the management of psoriasis in children
- Topical corticosteroids
- Vitamin D analogues (e.g. calcipotriol)
What are the most common birth marks in children?
- Salmon patch (stork mark)
- Infantile haemangioma (strawberry birthmark)
- Capillary malformation (port wine stain)
- Cafe-au-lait spots
- Mongolian blue spots
- Congenital melanocytic naevi (normal moles)
What are the clinical features of a salmon patch birthmark?
Is this type of birthmark common?
What is the prognosis?
- Flat pink/red patches on a baby’s eyelid, forehead or neck at birth
- Very common - occur in around half of all babies
- Fade completely in a few months
What are the clinical features of infantile haemangioma?
Are they more common in boys or girls?
What is the prognosis?
- Raised red mark on the skin
- More common in girls
- Rapidly increase in size up to 6 months, then begin to shrink - usually disappear by 7 years of age
What are the clinical features of capillary malformation (port wine stain)?
What is the prognosis?
- Flat red/purple mark
- Permanent
What are the clinical features of cafe-au-lait spots?
Can cafe-au-lait spots be a sign of another condition?
- Flat, light-brown patches
- Neurofibromatosis
What are the clinical features of Mongolian blue spots?
Which populations are they more common in?
What is the prognosis?
- Flat, dark purple/blue marks
- Usually appear over the lower back/buttocks
- More common in darker-skinned populations
- Usually disappear
