Infection and Rashes Flashcards
Define Macule
flat lesion ,usually a circumscribed change of colour
Define Papule
small , solid, elevated lesion
Define Nodule
a large , solid , palpable and elevated lesion
Define Plaque
Plaque – a lesion slightly raised over a larger area
Define Blister
Blister – an elevated lesion ,fluid filled
lesions
Define Ulcer
Ulcer – depressed lesion with loss of surface epithelium
Define Atrophy
Atrophy – a depressed lesion with intact surface epithelium
Define Crust
Crust – a mixture of scale and serum – yellowish accretions on the surface of a lesion
Define Petechiae
Petechiae – non raised red-brown non blanchable
Chicken pox virus
Varicella Zosta Virus
Stages of chicken pox
Virus enters upper respiratory tract
Day 4-6: Viraemia
Incubation period 10-14 days can be longer
First symptom pyrexia for up to 4 days
Headache, malaise, abdo pain
Crops of vesicles over 3-5 days on head neck and trunk (sparse on limbs)
Papule to Vesicle to Pustule to Crust
Management of chicken pox
analgesia – paracetamol for discomfort and pyrexia.
pruritis – antihistamine or calamine lotion
acyclovir only for those at risk of complications or immunocompromised.
Impetigo
Very common superficial, contagious, blistering bacterial infection
Types of impetigo
Non Bullous: Group A beta haemolytic strep pyogenes
Bullous: Fluid lesions (Staph. Aureus)
Presentation of non bullous impetigo
More common 70%
Usually aymptomatic. Occasionally pruritic
Tiny pustules or vesicles that evolve to honey coloured crusted plaques <2cm.
On face. Can be at extremeties where bites , abrasions, lacerations, burns, scratches or trauma could have occurred. Regional lymph nodes enlarged
Little or no surrounding erythema
Presentation of bullous impetigo
Occasionally pruritic. Can be painful
Usually on the face, trunk, extremities, buttocks, or perineal regions.
More common in neonates
Thin roofs and tend to rupture spontaneously
Diagnosis of impetigo
Clinical diagnosis if severe take swabs if:
?MRSA
It is severe or extensive
Recurrent or treatment is failing
Management of impetigo
Neonates: Abx, Erythromycin PO or Vancomycin IV (MRSA +)
Treatment superficial/limited: mupirocin, fusidic acid
Widespread cut. lesions: Oral Abx such as dicloxacillin or flucloxacillin, erythromycin
Deep tissue/systemic infection: Parenteral antibiotic therapy with nafcillin, oxacillin, or clindamycin
Erythema Multiforme
Hypersensitivity reaction resulting in papules forming over back of hands and feet spreading to trunk. Often involving the face. Papules then evolve to plaques and then typical target shaped lesions
Lesions have dusky red centre pale around it and then dusky red ring
Commonly associated with stevens johnson syndrome
Common infections associated with Erythema Multiforme
Herpes Simplex Virus
Mycoplasma Pneumoniae
Can also be:
Hep B, Epstein Barr virus, Cytomegalovirus and more (see BMJ)
Drugs associated with erythema multiforme
most commonly associated-Allopurinol
Recent drugs- Nevirapine, lamotrigine, sertraline, pantoprazole, tramadol
Antibiotics- Sulphonamides, including co-trimoxazole, penicillin cephalosporins, fluoroquinolones, vancomycin
NSAIDs- Piroxicam, fenbufen, ibuprofen, ketoprofen, naproxen, tenoxicam, diclofenac, sulindac
Anti-TB- Rifampicin, ethambutol, isoniazid, pyrazinamide
Anticonvulsants- Barbiturates, carbamazepine, phenytoin, valproate, lamotrigine
Classification of erythema multiforme
EM Minor: Typical targets or raised oedematous papules, with acral distribution, without involvement of mucosal sites and involving <10% total body surface area.
EM Major: Typical targets or raised oedematous papules, with acral distribution, with involvement of mucosal sites and involving <10% total body surface area.
Management of erythema multiforme
Supportive care to maintain hydration and prevent erosions from developing secondary bacterial infection
Treatment of suspected precipitating infections
Suppression therapy with antivirals if recurrent disease is caused by herpes simplex virus (HSV)
Topical or systemic corticosteroids to reduce inflammation.
Stevens Johnson Syndrome (SJS) and Toxic epidermal necrotitis (TEN)
More severe forms of eryrhema multiforme
SJS: <10% total body surface area (TBSA) involvement. Causes include Mycoplasma pneumoniae , viral infections, and vaccines, or drug-related.
TEN: >30% TBSA involvement. Drug-related
Clinical impression of stevens johnson syndrome and toxic epidermal necrotitis
Blisters or macules and flat atypical target lesions
diffuse erythema
Nikolsky’s sign (epidermal layer easily sloughs off when pressure is applied to the affected area)
Mucosal involvement presents with erosions or ulceration of the eyes, lips, mouth, pharynx, oesophagus, GI tract, kidneys, liver, anus, genital area, or urethra
One of the potential complications of SJS/TEN is mucosal involvement of the upper and lower respiratory tract, with vesicle formation, ulceration, and actual mucosal sloughing that may lead to laryngeal stridor, along with possible retractions and oedema of the nasopharynx
Wallace Rule of 9
Splits body into 9 parts allows assessment of the total body surface area an infection may cover:
Head and neck total for front and back: 9%
Each upper limb total for front and back: 9%
Thorax and abdomen front: 18%
Thorax and abdomen back: 18%
Perineum: 1%
Each lower limb total for front and back: 18%.
Management of SJS/TEN
ABG and Oxygen sats to assess for respiratoy distress Dressings with topical Abx Fluid management Analgaesia (avoid NSAIDs where possible) Opthalmic consultation
Kawasaki disease
acute, febrile, self-limiting, systemic vasculitis of unknown origin that almost exclusively affects young children
Presentation of Kawasaki disease
Fever lasting ≥5 days
Marked irritability of the child
Erythema, swelling and desquamation affecting the skin of the extremities
Bilateral conjunctivitis
Rash
Inflammation of the lips, mouth and/or tongue
Cervical lymphadenopathy
Complications of kawasaki disease
development of an acute coronary artery vasculitis with dilatation or aneurysm formation.
In addition, KD may lead to myocardial infarction, sudden death, and ischaemic heart disease.
Stages of kawasaki disease
Acute febrile stage: 1-2 weeks
Fever, irritability, cervical adenitis, conjunctivitis, rash, mucosal erythema, painful erythema of the hands and feet, arthralgia or arthritis, possible myocarditis, and pericarditis
Subacute: weeks 2-4
Fever, rash, and lymphadenopathy have resolved. Persistent irritability, poor appetite, and conjunctival infection, desquamation of extremities begins at this stage.
Patient may be completely asymptomatic if given intravenous immunoglobulin (IVIG)
Cardiac abnormalities develop
Convalescent weeks 4-8
All signs of inflammation have receded and acute phase markers normalise.
If present, coronary artery ectasia or aneurysms may persist and enlarge.
Chronic stage: If present, coronary artery dilation may resolve.
However, coronary artery aneurysms may persist through to adulthood. Such patients are at risk of subsequent coronary artery thrombosis, rupture, and myocardial infarction.
Management of Kawasaki disease
Intravenous Immune Globulin 2g/kg x1
Aspirin 80-100 mg/kg/day until fever settled for 14 day, then
3-5mg/kg/day x ≥ 6-8 weeks
Consider corticosteroids and infliximab for second line management
Also ensure Echocardiogram is carried out and cardiology follow up where necessary
Scabies
Highly contagious pruritic rash caused by parasitic mite sarcoptes scabiei. Manifests as rash usually 4-6 weeks after infection.
Clinical presentation of scabies
Widespread pruritus. Usually worse at night or when the person is warm.
Skin lesions can be macules, papules, pustules or nodules. Lesions seen on the site of the burrows
Burrows may be visible as fine, wavy, greyish, dark or silvery lines, 2-15 mm long, sometimes with a minute speck (the mite) at the closed end
Key investigations for scabies diagnosis
Clinical
Ink burrow test
Scabies management
Clothes, towels, and bed linen should be machine-washed (at 50°C or above) to prevent re-infestation and transmission. Items that cannot be washed can be kept in plastic bags for at least 72 hours to contain the mites until they die.
-benzyl benzoate lotion ,apply for 24hours ,may be repeated in 1 week
-permethrin cream
Babies <2 months -5% sulphur ointment
Measles
Highly infectious disease caused by measle virus (ssRNA Morbillivirus)
Mode of transmission of measles
airborne via respiratory droplets.
Measles symptoms
Prodrome - lasts 2-4 days with fever, runny nose, mild conjunctivitis and diarrhoea. Koplik spots are pathognomic and appear on the buccal mucosa opposite the second molar teeth as small, red spots each with a bluish-white speck (sometimes compared to a grain of rice) in the centre
Rash-first seen on forehead and neck and spreads, involves trunk and finally limbs over 3-4 days. It may become confluent in some areas. Rash then fades after 3-4 days in the order of its appearance. It leaves behind a brownish discoloration sometimes accompanied by fine desquamation.
Complications of measles
Neuro
Acute demyelinating encephalitis
Subacute sclerosing panencephalitis
Measles inclusion body encephalitis
Gastro- Diarrhoea
Resp-Bronchopneumonia
VitA def, and blindness
Immunodeficiency
Management of uncomplicated measles
paracetamol or ibuprofen and plenty of fluids. Patients should remain at home to limit disease spread.
MMR is already part of childhood immunisations
Post exposure prophylaxis of MMR vaccine to those who are susceptible (>6 months) ideally within the first 72 hours of exposure.
Erythema infectiosum
AKA slapped cheek disease due to parvovirus B19
Presentation of erythema infectiosum
Prodromal- week after infection. mild and may include headache, rhinitis, sore throat, low-grade fever and malaise.
Symptom free 7-10 days followed by slapped cheek rash. disappears after 2-4 days.
1-4 days after the facial rash appears, an erythematous macular/morbilliform rash develops on the extremities, mainly on the extensor surfaces.
Fades over the next 3-21 days
types of napkin dermatitis
Contact:
prolonged exposure to urine and faeces, friction mild erythematous ,glazed appearance
Seborrhoeic dermatitis:
Cradle cap in babies
salmon coloured greasy lesions and a predilection for intertriginous areas
Candidiasis:
beefy red in colour with pin point pustulo-vesicular satellite lesion
Management of napkin dermatitis
Frequent nappy changes
barrier cream zinc and caster oil
apply hydrocortisone 1% in aqueous cream bd
if candidiasis suspected -10% steriod and nystatin 20% in zinc cream
Molluscum contagiosum virus (MCV)
Skin infection as a result of MCV of the POX family . Spread by direct contact usually through sports and by sharing towels, baths and gymnasium equipment.
MCV1 most common. MCV2 common in immunosuppressed.
Presentation of Molluscum contagiosum
Firm, smooth, umbilicated papules, usually 2-5 mm in diameter
Usually it is asymptomatic but there may be tenderness, pruritus and eczema around the lesions
Usually on trunk an extremeties
No fever or malaise
Management of molluscum contagiosum
Tend to heal spontaneously within 6 months – 1 year
- liquid nitrogen 2-3 weeks
- express contents with sharp curette
- benzoyl peroxide cream apply daily
Eczema Tx
Emollient (Aveeno, E45)
Topical corticosteroids (1% hydrocortisone)
Occlusive bandages
Antibiotic with hydrocortisone for mildly infected eczema
Infantile seborrhoeic dermatitis
Cradle cap
Mild case resolved by emollient
Scales cleared with low concentration sulfur and salycilic acid
Urticaria
Hives normally due to viral infection or allergen exposure
Haemangioma
Collection of small blood vessels causing lump under skin at risk of ulcerating.
Common paediatric haemangiomas
Strawberry naevus: appear in first month and grow till 3-15months before reducing no need for treatment but can use topical propanol to speed process
Sturge-Webster syndrome: port wine stain facial lesions in distribution of trigeminal nerve. Can present with epilepsy, intellectual disability or contralateral hemiplagia
Diabetes triad
Polydypsia
Polyurea
Weight loss
Diagnosis of diabetes
Random glucose >11
Fasted glucose >7
Complications of diabetes
Hypoglycaemia
Diabetic ketoacidosis
Hypoglycaemia symptoms
Hunger
Tummy ache
Sweating
Feeling faint or dizzy
Signs of diabetic ketoacidosis
Acetone breath Vomiting Dehydration Abdo pain Hyperventilation (kussmajl breathing) Hypovolaemic shock Drowsiness Coma and death
Diabetic ketoacidosis ranges
Glucose >11.1 Ketones >3 U&E, creatinine (dehydration) Blood gas analysis (acidosis) T wave changes in hypokalaemia Weight loss Evidence of precipitating cause.
DKA management
Fluids: 0.9 saline 40mmol KCl 12h, 5% glucose added when <14. After 12hr id plasma stable 0.45 saline 40 mimol KCl
Insulin infusion 0.1 U/kg per Hr
Potassium as will fall when infusion starts
Avoid bicarbonate for acidosis should revolve with fluids
Restablish oral fluids
Identify cause
Hand foot and mouth disease
Painful vesicular lesions on hands, feet, mouth and tongue occasionally buttocks
Fifth disease
Human parovirus b19.
Slapped cheek rash, progressing to trunk
Aplastic crisis- in children with high red blood cell turnover or compromised immune system
Erythema toxicum
Common benign condition in neonates usually between 2-5 days. More common in full term neonates. Combination of macule, papule and pustules.
Hand foot and mouth disease
Coxsackievirus A16 virus and enterovirus 71
Hand foot and mouth disease presentation
Prodrome : Low grade fever, malaise, loss of apettite. sore mouth cough abdo pain
Hand foot and mouth lesions
Hand foot and mouth Tx
Supportive. No treatment
Refer if neurological symptoms occur (myoclonic jerk, severe headaches, or encephalitis -
Symptoms tend to resolve within 10 days
Glandular fever (infectious mononucleosis)
Epstein Bar virus
IM presentation
Low grade fever Malase Sore throar Non pruritic rash Nausea Arthralgia
