Dermatology Flashcards
What is the term for a rash (skin eruption) consisting of raised and flat lesions?
Maculopapular rash
Macules = flat lesions
What are Koplik spots?
Pathognomic for measles and occur 1-2 days before rash onset Usually located near lower pre-molars
Spots are small greyish-white surrounded by an erythematous base
What is the normal heart rate for a 4 year old?
110-160 bpm
Child patient has red maculopapular rash (morbilliform rash) starting on neck and face and spreading onto trunk and limbs Unwell with high fever and has viral prodromal symptoms (malaise, rhinnorhoea, non-purulent conjunctivitis)
Also has Koplik spots which precede the rash. What is the likely diagnosis?
Measles
What is the risk of catching measles if you have had the MMR vaccine?
Provides protection from measles in about 90% of its recipients
How is measles spread? And how long is it infective for?
Airbourne or droplet transmission
Period of infectivity is from start of prodromal symptoms to about 4 days after rash onset and then incubation period of 8-14 days
How do you manage a case of measles?
Supportive management: Keep patient hydrated and use anti-pyretics if patient unwell with the fever
Advice should be given both verbally and written. This should include keeping patient away from susceptible individuals until 5 days after rash onset
Advise on symptoms and signs to look out for indicating deterioration or developing complications
Send off saliva sample to laboratory to confirm diagnosis and report the case to the local public health agency. Measles is a notifiable condition
What are some potential complications of measles? In which groups are these complications more likely?
Otitis media (7-9%) Pneumonia (1-6%) Diarrhoea (8%) Convulsions (1/200) Encephalitis (1/1,000) Subacute sclerosing panencephalitis Death (1/5,000) Complications are more severe and more likely in infants, immunocompromised and poorly nourished and chronically ill children
5 year old girl with an itchy rash behind her knees and on both her wrists. She is well, she does not have a fever, her skin is noted to be dry and there are some excoriations. She has mild asthma for which she uses a salbutamol inhaler. What is the likely diagnosis?
Atopic eczema
What blood test results might be noted in a patient with atopic eczema?
Serum IgE may be raised and there may be an eosinophilia
What are excoriations?
Scratch marks/abrasions. Superficial breaks in the skin surface as a result of trauma such as scratching
4 year old boy, brought in to GP by his mum. Not been himself over last 3 to 4 days which she thought was due to a cold as he had a runny nose and red eyes. Noticed he had some spots on his face yesterday and today his rash has become much more
widespread. Rash consists of both flat and raised skin lesions with lesions being less than 5mm in diameter. Some of the lesions have merged and become confluent. What is your differential diagnosis?
Viral exanthem: rubella, measles, scarlet fever, roseola infantum, erythema infectiosum/fifth disease
Drug eruption
Allergic reaction
What signs would you look for to indicate skin infection?
Crusting, weeping, pustules, fever, tachycardia
Increased redness and heat to the skin
If an eczematous rash is infected, what bacteria is the likely cause and what antibiotics would you prescribe?
Staphylococcus aureus
Group A Streptococcus
If no penicillin allergy, flucloxacillin would be first line
What is lichenification and why does it occur?
Thickening of epidermis (with exaggeration of normal skin lines/markings)
Usually due to chronic rubbing/scratching. Skin is described as feeling leathery and is usually discoloured
What is diprobase and what is its purpose?
Emollient cream to keep skin hydrated
Dry skin means barrier function has been impaired allowing allergens and irritants to penetrate it easier
Use emollients liberally, best applied when skin is wet following a shower/bath and should be used even when there is no sign of
eczema to prevent flare-ups
What is hydrocortisone and how is it used in eczema?
Hydrocortisone 1% ointment is a topical corticosteroid
Purpose is to reduce inflammation
Potency and duration of treatment should be kept to minimum
Typically prescribed for 5-7 days
Management depends on severity of eczema, location of the rash, age of patient, previous treatment, presence of complications such as infection, psychosocial effects of rash eg not sleeping, poor self-esteem
Why are we cautious when prescribing corticosteroids? Who is particularly susceptible to adverse effects?
Children and elderly especially susceptible to adverse effects because they have a thinner epidermis
Local adverse effects : Thinning of skin, striae, worsening and spreading of infection
Systemic adverse effects: growth retardation, Cushing’s syndrome, adrenal suppression
Why is contact dermatitis different from eczema?
Eczema: widespread distribution
Contact dermatitis: localised and unusual distribution
What is the underlying mechanism for contact dermatitis?
Chemically induced irritation (irritant eczema) or allergic sensitisation (type 4 hypersensitivity reaction to environmental chemical sensitisers)
Allergic sensitisation: at sites that make physical contact with eliciting sensitiser in those susceptible to developing an allergic reaction
Irritant eczema: after exposure (repeated) to an irritant and can occur in anybody. It does not have an immunological cause, the irritant itself causes inflammation through tissue damage
What infectious agent causes chickenpox?
Herpes zoster - a DNA virus
What type of lesion is seen in chickenpox?
Vesicles all over the body
How do you manage a case of chickenpox?
Supportive treatment: Fluids, Paracetamol if symptomatic with fever, Anti-histamines and calamine lotion can be helpful for itch
Advice (e.g. regarding infectivity) and safety-netting
What are risks to pregnant women with chickenpox exposure?
Need to know if they have previously had chickenpox or previously been checked for varicella antibodies
If they have no antibodies to VZ virus then she should be given varicella zoster immunoglobulin (VZIG)
Risk of congenital varicella syndrome (until 20 weeks gestation) which causes a range of problems including intrauterine growth restriction, microcephaly, limb hypoplasia, cataracts and cutaneous scarring. Infection at a later stage of pregnancy can cause premature delivery or neonatal chickenpox. The most severe chickenpox occurring if the infant is born within seven days of the onset of the mothers rash
