Pediatric Dermatology Flashcards
Why is measles very contagious?
It is airborne contagious, and can be transmitted 4 days before rash onset to 4 days after rash onset
Can survive on fomites for up to 2 hours
What is the prodrome of measles and how does the rash spread? What’s the morphology of the rash?
Prodrome: 4 C’s
Cough, Coryza, Conjunctivitis, Koplik’s spots
Rash starts on forehead and spreads towards feet, becoming confluent (dress in sketchy with falling rubies). It is genuinely a maculopapular rash
What is one thing that should always be given to treat measles and why?
Vitamin A - it is significantly reduced early in exanthem. Children treated with Vitamin A recover more rapidly from pneumonia and diarrhea, lower morbidity and mortality.
Think of the vitamin A partyhat in sketchy
What is the pattern of the rubella exanthem? What other symptoms are associated? What is the oral finding?
Typically an occipital or postauricular lymphadenopathy
Associated with pinpoint macules starting on face spreading all the way down the body, unlikely to become confluent (vs measles).
What is the enanthem of rubella?
Forchheimer’s spots - soft palate petechiae
An enanthem is a rash inside the body
Exanthem is a rash on the external surface of the body
What adults typically get manifestations of rubella, and what are they?
Typically women. Transient polyarthritis particulary affecting phalangeal joints and knees.
What is the triad of Rubella which affects children?
- Patent ductus arteriosus
- Congenital cataracts
- Blueberry muffin rash - due to extramedullary hematopoiesis
What virus causes erythema infectiosum? How do children vs adolescents present differently?
Parvovirus B19 (fifth disease)
Children - slapped cheap rash which waxes and wanes, children are NOT viremic at presentation
Adolescents - papular-purpuric gloves and socks syndrome! - they ARE viremic at presentation
What are the two phases of erythema infectiosum following the slapped-cheek phase?
- Net-like erythema - fishnet-like erythematous eruption begins on extremities 2 days after slapped cheek rash, extending to trunk and buttocks, fading within two weeks
- Recurrence phase - rash may fade and reappear over next 2-3 weeks.
What are the feared complications of parvovirus B19 and should children be excluded from school?
- Transient aplastic crisis in Sickle Cell patients
- Hydrops fetalis in pregnancy
Children should not be excluded from school since they are not viremic
Is roseola common? What virus is the cause? How is it spread?
HHV-6 = Rose-6-ola
Extremely common, 80% of children seroconvert in first year of life
Virus remains latent in monocytes, macrophages, CD4+ T cells and salivary glands
-> spread through saliva from mother to child
What rash is characteristic of roseola? Name that rash.
Think Rose-6-o-Later
Exanthem subitum - 6th disease
HHV-6 causes a macular rash which spreads LATER than the fever (4 days later). First there is a high fever then a diffuse macular rash once the fever has subsided which often spares the face
What type of rash is measles said to cause?
“Morbilliform” - literally meaning measles-like
What are the three main toxic erythemas?
- Scarlet fever
- Staphylococcal Scalded Skin Syndrome
- Mucocutaneous lymph node syndrome (Kawasaki disease) -> toxin unknown
What is the clinical presentation of all toxic erythemas? One of these is inconsistent with the three syndromes.
- Fever
- Sandpaper-like rash where skin turns red, and will ultimately desquamate
- Mucous membranes are involved (exception: Staphylococcal Scalded Skin Syndrome).
What is the significance of mucous membranes not being involved in SSSS?
It is the only toxic erythema which does not cause oral mucositis
-> Kawasaki and Scarlet Fever will cause STRAWBERRY TONGUEs.
What is the triad of Scarlet Fever?
Think of the guy eating a strawberry in sketchy, with a neckerchief, and painting a gingerbread man.
- Strawberry tongue
- Strept pharyngitis
- Diffuse rash which typically spares the face
Describe the rash of scarlet fever and how it heals? What are the linear petechial streaks it is associated with and where are they found?
Fine, erythematous papules around the body healing via desquamation
Linear petechial streaks: Pastia’s lines - seen in axillary, antecubital, and inguinal areas
How does a strawberry tongue typically progress? What toxins mediate the progression of this disease in scarlet fever?
Oral enanthem -> white tongue coating
4-5 days later, white coating is sloughed off and leaves classic red strawberry tongue / beefy red tongue
Streptococcal pyrogenic exotoxins (erythrogenic toxins) - SpeA-C
What is bullous impetigo, and what is the cause of the systemic form of this disease?
Bullous impetigo is the localized form of SSSS, which in this case you would be able to culture S. aureus locally
Systemic form is SSSS, and is caused by toxins circulating throughout body distant from site of infection.
-> Staphylococcal exfoliative toxins cause INTRAepidermal splitting by cleaveage of desmoglein 1 in desmosomes
What pathology does SSSS cause? Is Nikolsky sign positive or negative?
Causes flaccid bullae since it’s intraepidermal. Nikolsky sign will by positive, like pemphigus vulgaris (pressing on the skin can create blisters due to circulating toxin which cleaves desmosomes)
How should you diagnose and treat SSSS? Will children be bacteremic?
Should culture specimens from nose, throat, umbilicus in neonates, and any obviously infected areas to check for MRSA, then treat based on antibiotic susceptibility.
Patient may need to be admitted to burn unit, give aggressive fluid replacement
Skin and blood culture is often negative in children
What is the major cause of Toxic Shock Syndrome now, and what will the rash look like? What will happen to blood pressure?
Usually seen more now with post-operative patients (especially following rhinoplasties, “nasal packing” with tampons to control bleeding, pg 131). Used to be caused by vaginal tampons.
Generalized erythroderma over large body surface area, with desquamation especially of palms and soles 1-2 weeks after onset.
Severe hypotension occurs due to systemic cytokine release.
What labs are commonly elevated in TSS?
ALT, AST, and bilirubin -> end-organ liver damage.
Also causes renal failure (elevated BUN), and acute ischemic encephalopathies
What is the other name for Kawasaki disease and who tends to get it? What is the characteristic ocular finding? What type of disease is it?
Mucocutaneous lymph node syndrome
Tends to occur in children <4 years old, especially Asians
Ocular finding - conjunctival injection WITHOUT purulent discharge
Multisystem vasculitis