Pertussis / Parapertussis (Whooping Cough, 100 Day Cough)
Epidemiology
Mortality 0.5-1% if <6/12; 25% adult prolonged cough are due to pertussis
Pathophysiology
Aetiology: Bordatella pertussis (G –ive); parapertussis as common in 2-6yrs, but less common outside
these
Incubation period: 1/52
Symptoms
1-2/52 catarrhal phase  4-6/52 paroxysmal cough (assoc with vomiting, cyanosis; apnoea in young
infants)  recovery over 2-3/52
Complications
Bronchopneumonia: in 25% <4yrs
Seizures: in 2%; due to hypoxia from coughing
Others: otitis media, intracerebral haemorrhage, subconjunctival haemorrhage, facial petechiae,
encephalopathy, rectal prolapse, inguinal hernia
Investigations
NPA: do within 2/52 onset of cough
Other: PCR, ELISA
Management
O2, suction
Antibiotics: azithromycin: <6/12 = 10mg/kg OD PO
>6/12 = 10mg/kg (max 500mg) PO  5mg/kg (max 250mg)OD PO
for 5/7
Consider admission if: <6/12 (risk of apnoea)
Contact prophylaxis: if <3 doses vaccine, >36/40, or attends their daycare; give azithromycin as above
Differential
Diagnosis
Angioedema, diphtheria, laryngospasm, anterior mediastinal tumour, epiglottitis, bacterial tracheitis,
retropharyngeal abscess, severe tonsillitis, foreign body aspiration
Scarlet Fever
Aetiology: Group A beta-haemolytic strep
 erythrogenic toxin
Incubation: 2-4/7 (ie. Short)
Symptoms: Acute onset fever, sore throat, headache, vomiting, abdominal pain  exanthem develops
over 1-2/7
Red tonsils and pharynx covered in exudates; Bright red / haemorrhagic spots on soft palate
Tongue white coating through which red hyptertrophied papillae project (white strawberry tongue)
 White coating disappears after 4-5/7  red strawberry tongue
After 12-48hrs  Red, finely punctate 1-2mm blanching papules (rough sandpaper) on neck, axillae and
groin  Rapidly spreads to trunk and extremities
Linear petechial eruptions in antecubital and axillary folds (Pastia’s lines)
Facial flushing and circumoral pallor
 Fades at 6/7  Desquamates at 2/52, on hands and feet 1st
Complications: otitis media, sinusitis, rheumatic fever, post-strep glomerulonephritis
Investigations: ASOT, swab
Treatment: Penicillin 10/7
Aetiology: RNA myxovirus
Epidemiology: rare in immunised; now mostly seen in older patients;
highly infectious (90% susceptible close contacts will become infected
Incubation: 7-18/7 (av 10/7); 14/7 between exposure and rash; patient
infectious from 5/7 before rash to 4/7 after rash
Measles
Case definition: 3-4/7 URTI  rash
1. Fever >38 (ie. High)
2. Rash: fever always present at time of onset of rash; behind
ears and at hairline  spreads from head to feet, inc palms
and soles; erythematous maculopapular, red blanching 
confluence esp on face  copper-brownish hue as resolves
 desquamates after 3/7; lasts 1/52
3. 1 of cough / coryza / conjunctivitis / Koplick spots (white,
bluish-white 1mm spots with red base on buccal mucosa;
appear 1/7 before rash); may have generalised
lymphadenopathy; may be diarrhoea
Complications: otitis media (2.5%), pneumonia (4%; responsible for 50% deaths); encephalitis (0.1%;
onset 1-2/52 after disease; mortality 10-15%; permanent neuro damage in 40%); subacute sclerosing
panencephalitis (can occur 4-10yrs later, progressive mental deterioration and death); myocarditis,
nephritis, hepatitis, pericarditis, keratitis
Investigations: swab for PCR (will be +ive within few days, when serology may still be negative; also
useful in immunocomp); blood for serology (IgM = infection, levels peak at 7-10/7; IgG = immunity; may
be negative if <4/7 from onset fever, need to do repeat after 1/52, remains +ive for 3/12, sensitivity
100%, specificity 98%); double bag specs and don’t send through lamsen
Treatment: Supportive; need infection control measures; notifiable disease; no school / child care for
5/7; admit if: poor PO intake, respiratory compromise, CNS complications
Prophylaxis: Exposed if: enter same room within 2 hours of infected person leaving
Non-immune if: not had 2x MMR and born after 1969, from 6/12 to 1st vaccine, if >4yrs and
not had 2nd vaccine, pregnant, immunocomp, or prem <28/40
Offer MMR if <72hrs (not if pregnant); if immunocompromised / pregnant / >72hrs,
consider Ig
Henoch
Scholein
Purpura
(HSP)
is NOT a
platelet
problem
Epidemiology: 2:1000; more Asian / Indian; usually 4-6yrs (2-11yrs)
Aetiology: Allergic vasculitis, follows URTI, IgA mediated;
associated with infection, drugs, vaccines; may be post Grp A
strep
Pathology: Small vessels (skin, GI tract, kidneys, joints)
Symptoms: Palpable purpura on buttocks and legs (extensor
surface) – presenting symptom in 50%; maybe also
erythematous, urticarial, echymoses, petechaie
Abdominal pain (+ nausea, vomiting, diarrhoea; in 60-80%;
diffuse and colicky; occurs after rash; 50% have blood in
stool; 5% get acute GI haemorrhage; 3% get
intussusception)
Migratory polyarthralgia (66-80%; presenting symptom in 25%;
usually resolves after 24-48hrs; in gravity dependent joints)
Renal failure (in 20-50%) – nephritic syndrome
Generalized oedema (eg. Feet; often painful)
Investigations: haematuria and proteinuria in 90%; urine, FBC
(platelets normal); U+E’s
Complications: Nephritic / nephrotic syndrome, ARF (<1%), HTN; if proteinuria = more severe and needs
follow up; Intussusception (5%); bowel perforation
Management: Usually resolves in 3-4/52; supportive; monitor BP and urine for 6/12; IV fluids if ill;
NSAIDS; Consider prednisone 1mg/kg for 2/52 (if abdominal, joint or scrotal disease; may prevent renal
complications (2% get long term renal impairment); helps joint pain, abdominal pain, oedema)
Admit if: abdominal, renal complications; symptomatic relief
Echovirus
9,
Coxsackie
virus A9
Enteroviruses
Enterovirus
(hand,
foot and
mouth
disease)
Coxsackie
virus
(herpangina)
Transmission: Fecal-oral, oral-oral, respiratory-oral
Symptoms: Non-specific febrile illnesses, respiratory tract infection, GI symptoms,
meningitis; variety of rashes; Maculopapular rash beginning on face and neck,
extending to trunk and feet; may be lesions on buccal mucosa and soft palate
(resemble Koplik spots); maybe petechiae, vesicles, urticaria
Duration: 5/7
Symptoms: Fever, anorexia, malaise, sore
mouth  1-2/7 later, oral lesions  then
cutaneous lesions
Oral lesions: painful 4-8mm vesicles on
erythematous base on buccal mucosa,
tongue, soft palate, gingiva  ulcerate
Cutaneous lesions: 3-7mm red papules
 grey vesicles on palms and soles (may
be dorsum of feet and buttocks)  heal in
7-10/7
Treatment: Hydration, analgesia, mouthwash
Symptoms: Fever, mouth pain, oral ulcers
Similar ulcers to hand, foot and mouth, but no
skin lesions
Rubella
Erythema
Infectiosum
(Fifth Disease,
Slapped Cheek)
Incubation: 12-25/7
Symptoms: 1-5/7 fever, malaise, headache,
sore throat  irregular pink macules and papules
on face, spreading to neck, trunk and arms;
coalesces then clears
Forchheimer spots: pinpoint petechiae on soft palate
that coalesce
Suboccipital and posterior auricular lymphadenopathy
Treatment: Supportive
Symptoms: Abrupt appearance of rash  fiery red rash on
cheeks; diffuse erythema of closely grouped tiny papules on
erythematous base; edges slightly raised; circumoral pallor;
sparing of eyelids and chin; lasts 4-5/7
1-2/7 after face rash  nonpruritic macular/maculopapular
erythema on trunk and upper limbs  spreads; lasts 1/52;
spares palms and soles; fades with central clearing
Associated with fever, malaise, headache, sore throat, cough,
coryza, nausea, vomiting, diarrhoea, myalgia
Treatment: Supportive
Herpes
Transmission: HSV-2 genital, HSV-1 oral
Symptoms: Herpes labialis, gingivostomatitis – painful umbilicated
vesicles  unroof and crust over
Eczema herpiticum – break out on area previously affected by eczema
Herpetic whitlow – distal fingers
Treatment: Consider sexual abuse; Oral acyclovir; supportive
Chickenpox
Symptoms: Pruritic generalized vesicular exanthem with
mild systemic symptoms; starts on trunk / scalp as faint
red macules  vesicular in 24hrs, on erythematous
base  dry and crust; widespread, palms and soles
spared; may occur on mucous membranes
Treatment: Supportive if uncomplicated; cleanse lesions
to prevent secondary infection; antivirals only if
immunocompromised
If neonate exposed: nil treatment, present if develops
chickenpox then treat with IV aciclovir
Roseola
Infantum (Sixth
Disease)
Impetigo
Staph Scalded
Skin Syndrome
Erysipelas
Scabies
Symptoms: Abrupt onset of fever lasting 3-5/7, cough,
coryza, anorexia, abdominal discomfort  fever settles
 appearance of rash over 1-2/7. Erythematous,
blanching, macular/maculopapular eruption, discrete
rose / pale pink 2-5mm lesions; most on neck, trunk and
buttocks; can also involve face and arms. No mucous
membrane involvement. Lasts 1-2/7  fades rapidly.
Treatment: Supportive
Aetiology: Staph aureus, beta-haemolytic strep
Symptoms: Lesions on face, neck, and extremities; usually no systemic
symptoms
Nonbullous: small erythematous macules and papules  thin walled
vesicles  pustules  rupture  golden yellow crust  smooth red
surface underneath; may become confluent; local
adenopathy
Bullous: local; toxin causes separation of skin and bullae;
thin walled bullae 0.5-3cm, filled with clear-yellow fluid,
rupture easily
Treatment: Nonbullous: topical; oral only if severe
Symptoms: systemic; malaise, fever, irritability, tender skin;
extensive areas of exfoliation; Nikolsky
Treatment: inpatient, IVABx; may require admission to
Burns unit
Aetiology: Group A beta-haemolytic strep
Symptoms: Fever, chills, malaise, vomiting; Local redness, heat, swelling;
raised indurated border; well demarcated
Treatment: Penicillin / erythromycin
Symptoms: Severe pruritis; generalized eruption of linear burrows, papules,
pustules, vesicles; mostly affect hand, feet, groin; excoriation from
scratching
Treatment: Permethrin
Erythema
Toxicum
Seborrhoeic
Dermatitis
Symptoms: Erythematous macules 2-3cm on face, trunk,
extremities; central 1-3mm pustules
Treatment: None
Symptoms: Greasy yellow/red scales, mostly on scalp; not pruritic
Treatment: Mineral oil