Dermatology Flashcards
What is exanthem?
Eruptive widespread rash.
What are the viral exanthemas?
First disease.
Measles
What are the viral exanthemas?
Second disease.
Scarlet fever
What are the viral exanthemas?
Third disease.
Rubella (AKA German measles)
What are the viral exanthemas?
Fourth disease.
Dukes’ disease
What are the viral exanthemas?
Fifth disease.
Parvovirus B19
What are the viral exanthemas?
Sixth disease.
Roseola infantum
Presentation of first disease.
Measles:
- fever
- coryzal sx
- conjunctivitis
- white spots on buccal mucosa
Rash:
- starts on face
- spreads to rest of body
- macular rash
- erythematous
Management of measles.
Isolate until 4 days after symptoms resolve.
Supportive treatment.
Notifiable disease.
Complications of measles.
- pneumonia
- diarrhoea
- dehydration
- encephalitis
- meningitis
- hearing loss
- vision loss
- death
What is the cause of scarlet fever?
Exotoxin produced by streptococcus pyogenes bacteria.
Presentation of Scarlet fever.
Rash:
- sandpaper skin
- red/pink
- blotchy
- flushed
Other features:
- fever
- lethargy
- flushed face
- sore throat
- strawberry tongue
Treatment of Scarlet fever.
Phenoxymethylpenicillin for 10 days.
Keep off school for first 24 hours of antibiotics.
Notifiable disease.
Presentation of rubella.
Rash:
- erythematous
- macular
Other features:
- mild fever
- joint pain
- sore throat
- lymphadenopathy
Treatment of rubella.
Self-limiting / supportive therapy.
Notifiable disease.
Stay off school.
Avoid pregnant women.
Complications of rubella.
- thrombocytopenia
- encephalitis
Triad of congenital rubella syndrome.
- deafness
- blindness
- congenital heart disease
Cause of fifth disease.
Parvovirus B19
Features of fifth disease.
- slapped cheeks
- reticular rash on trunks and limbs
- raised and itchy
Other sx:
- mild fever
- coryza
- non-specific viral symptoms
Management of fifth disease.
Self-limiting (1-2 weeks).
Infectious prior to rash forming; once rash has developed not infectious so can go to school.
Which patients are at risk of complications of Fifth disease?
- immunocompromised patients
- pregnant women
- haematological conditions
Complications of Parvovirus B19 infection.
- aplastic anaemia
- encephalitis / meningitis
- pregnancy complications (ie. fetal death)
- hepatitis
Aetiology of Sixth disease.
Roseola infatum - caused by HHV-6.
Presentation of Sixth disease.
Sudden fever for 5 days;
THEN
Rash:
- mild erythematous macular rash
- not itchy
Management of roseola infantum.
Self-limiting (1 week)
No need to keep off nursery if they are well enough to attend.
Complications of roseola infantum.
- febrile convulsions
- myocarditis
- thrombocytopenia
- Gullain-Barre syndrome
What is erythema multiforme?
An erythematous rash caused by a hypersensitivity reaction:
- HSV 6 and 11
- mycoplasma pneumonia
- medications
Presentation of erythema multiforme.
Widespread, itchy, target lesions.
Aetiology of chickenpox.
- VAV
Presentation of chickenpox.
Widespread vesicular rash.
- fever
- itch
- general fatigue / malaise
At what point is chickenpox no longer contagious?
When the lesions scab over (5-7 days after appearing).
Complications of chickenpox.
- bacterial superinfection
- dehydration
- conjunctival lesions
- pneumonia
- encephalitis
Long-term complications of chickenpox.
After infection, the virus lays dormant in the sensory dorsal root ganglion cells.
It can reactive as:
- shingles
- Ramsay Hunt syndrome
Management of chickenpox in children.
Usually a mild self-limiting condition that does not require treatment.
Symptomatic treatment:
- calamine lotion
- clorphenamine
- cut finger nails
Keep child off school until rash blisters over.
Aetiology of hand, foot and mouth disease.
Coxsackie A virus
Presentation of hand, foot and mouth disease.
Viral URTI sx.
- mouth / tongue ulcers
- blistering on hands and feet
Management of hand, foot and mouth disease.
Supportive management:
- adequate fluid intake
- simple analgesia
Highly contagious therefore measures to prevent transmission:
- avoid sharing towels and bedding
- washing hands
- careful handing of dirty nappies
Complications of hand, foot and mouth disease.
- dehydration
- bacterial superinfection
- encephalitis
What is molluscum contagiousum?
A viral skin infection caused by poxvirus.
Features of molluscum contagiosum.
- small, flesh coloured papules
- central dimple
Management of molluscum contagiosum.
Resolve themselves without treatment; however this can take up to 18 months.
Avoid sharing towels or other close contact with lesions, to minimise risk of spreading the infection.
Complications of molluscum contagiosum.
As a result of scratching:
- bacterial superinfection
- scarring
- spreading lesions
Aetiology of pityriasis rosea.
Unknown - thought to be caused by a virus but no definitive cause has been established.
Presentation of Pityriasis rosea.
Rash:
- herald patch
- christmas tree lesions over trunk
Other symptoms may be present:
- generalised itch
- low grade pyrexia
- headache
- lethargy
Disease course - pityriasis rosea.
Resolves without treatment within 3 months.
May leave discolouration of the skin where the lesions were, however these will also resolve within another few months.
Management of pityriasis rosea.
No treatment - resolves spontaneously without any long term effects.
Not contagious.
Emollients, topical steroids or sedating antihistamines may help with any generalised itch.
Pathophysiology of seborrhoeic dermatitis.
Malassezia yeast colonisation of the sebaceous glands causes erythema, dermatitis and crusted dry skin.
Presentation of infantile seborrhoeic dermatitis.
AKA cradle cap.
Crusted and flaky scalp.
Management of infantile seborrhoeic dermatitis.
- Apply baby oil + gently brush scalp
- White petroleum jelly overnight
- Anti-fungal cream (e.g. clotrimazole, miconazole)
Presentation of seborrhoeic dermatitis of the scalp.
Flaky itchy skin on the scalp.
More commonly occurs in adolescents and adults rather than children.
Management of seborrhoeic dermatitis of the scalp.
Ketoconazole shampoo - leave on for 5 minutes then wash off.
Topical steroids may be used if there is severe itching.
Management of seborrhoeic dermatitis of the face and body.
Topical anti-fungal cream:
- clotrimazole
- miconazole
Localised inflammation may benefit from topical steroids.
What is nappy rash?
Friction between the skin and nappy, and contact with urine and faeces in a dirty nappy, results in a contact dermatitis.
Risk factors for nappy rash.
- delayed changing of nappies
- irritant soap products
- poorly absorbent nappies
- diarrhoea
- pre-term infants
Presentation of nappy rash.
Rash appears in patches of exposed skin that comes in contact with the nappies, with sparing of the skin creases:
- sore
- red
- inflammed
Management of nappy rash.
- highly absorbent nappies
- change the nappy and clean skin as soon as possible after wetting or soiling
- use water or alcohol free products for cleaning the nappy area
- ensure the nappy area is dry before replacing the nappy
- maximise time not wearing a nappy
Complications of nappy rash.
- candida infection
- cellulitis
- erosions
- ulceration
- Jacquet’s erosive diaper dermatitis
Differentials for a non-blanching rash in children.
- meningococcal septicaemia
- henoch-schonlein purpura
- ITP
- acute leukaemia
- HUS
- viral illness
Investigating non-blanching rashes.
Management of non-blanching rashes in children.
What is erythema nodosum?
Red lumps appear across the patient’s shins due to inflammation of the subcutaneous fat.
Causes of erythema nodosum.
- IBD
- sarcoidosis
- tuberculosis
- pregnancy
- streptococcal throat infections
- lymphoma
- leukaemia
Presentation of erythema nodosum.
Red, inflamed, subcutaneous nodules across both shins.
Nodules appear raised and can be painful or tender.
Investigating erythema nodosum.
Diagnosis is based upon clinical presentation - investigations can help identify the underlying cause:
- CRP and ESR
- throat swab (streptococcal infection)
- CXR
- stool microscopy and culture
- faecal calprotectin (IBD)
Management of erythema nodosum.
Conservative management with rest and analgesia - steroids may be used to help settle the inflammation.
Treatment of underlying cause is paramount.
Pathophysiology of staphylococcal scaled skin syndrome (SSSS).
Staphylococcus aureus produced epidermolytic toxins, causing the skin to become damaged and broken down.
Presentation of staphylococcal scaled skin syndrome.
- Patches of erythema
- Thin and wrinkled skin
- Bullae form
Nikolsky sign - gentle rubbing of the skin causes it to peel away.
