2. How to describe a rash
Recognise the visual diagnoses for paediatric rash
presentations
Patterns, distribution, special features
Broaden differentials for rash and identify the
commonly misdiagnosed presentations
Treatments for rash
Recognise the critical rash
Objectives
3. Anatomy
Epidermis
- Protective barrier
- melanin and immune
Dermis
- sweat:
- Nerves
- Sebaceous:
- blood vessels
Hypodermis (Subcut fat)
- Attaching the dermis to your
muscles and bones:
- blood vessels and nerve
cells:
- Controlling your body
temperature:
- Storing your fat
4. Macule –
Circumscribed are of change <1cm
Patch –
Large area of skin change
Papule –
solid raised lesion <1cm
Nodule –
solid raised lesion >1cm
Plaque –
circumscribed confluent area of nodules
Vesicle –
fluid filled are <1cm
Bulla –
fluid filled area >1cm
Pustule –
circumscribed area containing pus
Furuncle –
skin abscess (usually from staph)
Carbuncle –
collection of furuncles connected
Describing a rash
6. 4 year old child brought in by parents. Itching
vigorously.
Common Rashes
7. Highly contagious skin infestation by
the mite Sarcoptes scabiei
itchiness and a pimple-like rash
1st infection: symptoms in between two and six weeks
Second infection: Sxs develop in 24 hours
Symptoms secondary to an allergic reaction (Type IV)
zigzag or S pattern of the burrow will appear across
the skin
Rx: Permethrin
1. Scabies
14. Infant
4months to 5
years
Cheeks
Extensor surfaces
Diaper area
4. Atopic Dermatitis (Eczema)
3 year old - adult
Flexor surfaces
Neck
Face
Upper chest
Rx: steroids and moisturisers
Cotton clothing
Dry well after bathing
Antibiotics for superimposed infection
16. Staphylococcus aureus or Streptococcus pyogenes
Highly contagious
Treated with mupirocin ointment or POABs
E.g Flucloxacillin
Isolate from day care
Occasionally admit
Risk of leading to Osteomyeltisis and PSGN
5. Impetigo
21. The majority of Exanthems are nonspecific and
difficult to categorise
Associated with non specific sxs like headache,
lethargy, mayalgia and GI complaints
Most resolve in less than a week
Cause
Thought to be from enteroviruses and
adenovirus/rhinovirus/parainfluenza
Non specific Viral Rash
(exanthomata)
22. First Disease
Measles
Second Disease
Scarlet Fever
Third Disease
Rubella
Fourth Disease
Dukes -Controversial (possibly a misdiagnosis)
Fifth Disease
Erythema Infectiosum (Parvovirus B19)
Sixth Disease
Roseola (HHV6)
Specific Exanthems
24. Incubation: 7-14 d
Prodrome: 4 -5 d before rash
fever, malaise, rhinorrohea, cough,
Koplik spots 1-3 d before rash
Rash: day 4-7 of illness
starts behind ears, forehead, around mouth
dusky red, florid maculopapular rash spreads
over trunk and limbs. Lasts 5 d.
Infectivity: prodrome to 4 d after the rash
Transmission: respiratory droplet or direct contact
Complications: ears & OM,
lungs & pneumonia
conjunctivitis
CNS encephalitis at d 10, SSPE after several years
Measles
26. Also called German Measels
often mild with half of people not realizing that they are
infected
A rash may start around two weeks after exposure and last
for three days
starts on the face and spreads to the rest of the body
Infection during early pregnancy (below 20 weeks) may
result in a child born with congenital rubella
syndrome (CRS) or miscarriage.
Once recovered, people are immune to future infections.
Vaccine preventable
Rubella
28. Can occur as a result of a group
A streptococcus (group A strep) infection
It most commonly affects children between five and
15 years of age
Complications:
Suppurative: peritonsillar or retropharyngeal
abscesses, cellulitis, mastoiditis or sinusitis
Non-suppurative: Rheumatic fever, RHD, PSGN,
Reactive Arthritis
Scarlett fever
30. Roseola (6th disease)
- 3 year old child presents with 3 day history of fevers,
cough and runny nose
- Fevers stopped yesterday but suddenly patient woke up
with this rash.
35. Spectrum of disease
Widespread blisters predominant on the trunk and
face, mucous membrane erosions;
SJS: epidermal detachment is less than 10% TBSA
TEN: epidermal detachment is more than 30% TBSA
Cross over between 10-30%
SJS/TENS
36. Often start with fever, sore throat, cough, and burning
eyes for 1 to 3 days
Type IV hypersensitivity reaction – secondary to immune
system being triggered by drugs/infections
Ulcers and other lesions begin to appear in the mucous
membranes
- almost always in the mouth and lips, but also in the genital
and anal regions.
Problems eating and drinking due to pain of ulcers
Conjunctivitis occurs in about 30%
Rash of round small lesions arise on the face, trunk, arms
and legs, but usually not the scalp
SJS/TENS
37. Mortality rate:
5% for SJS
30-40% for TENS
Treatment
discontinuation of the causative factor – most important
Move to a burns unit
Supportive cares and IVH
IV anti-biotics
Immunomodulatory: steroids,
cyclophosphamide, plasmapheresis, acetylcysteine, infliximab
SJS/TENS
DX by skin scrapping
Permethrin is not an anti-biotic. It is an insecticide
Scabies is most often spread during a relatively long period of direct skin contact with an infected person (at least 10 minutes) such as that which may occur during sex or living together.
The elderly, disabled, and people with an impaired immune system, such as HIV, cancer, or those on immunosuppressive medications, are susceptible to crusted scabies (also called Norwegian scabies). – can also get this when you just get a severe infestation of scabies (above 2 million)
applied from the neck down, usually before bedtime, and left on for about eight to 14 hours, then washed off in the morning.[11] Care should be taken to coat the entire skin surface, not just symptomatic areas; any patch of skin left untreated can provide a "safe haven" for one or more mites to survive. One application is normally sufficient, as permethrin kills eggs and hatchlings, as well as adult mites, though many physicians recommend a second application three to seven days later as a precaution. Crusted scabies may require multiple applications, or supplemental treatment with oral ivermectin
Propionibacterium acnes
overgrowth. Is normally a skin commensal
- Genetics is thought to be the primary cause of acne in 80% of cases
- higher than normal amount of oily sebum production (influenced by testosterone),
Macrolides e.g Erythromycin/Minocyclin have anti-inflmmatory properties too why it is useful. That is why erythromycin used in some lung diseases e.g Bronchiectasis
Isotrenitoin - roacutane
The main difference between the rash caused by allergic contact dermatitis and the one caused by irritant contact dermatitis is that the latter tends to be confined to the area where the trigger touched the skin, whereas in allergic contact dermatitis the rash is more likely to be more widespread on the skin. Another characteristic of the allergic contact dermatitis rash is that it usually appears after a day or two after exposure to the allergen, unlike irritant contact dermatitis that appears immediately after the contact with the trigger.
The cause is unknown but believed to involve genetics, immune system dysfunction, environmental exposures
hose who live in cities and dry climates are more commonly affected. Exposure to certain chemicals or frequent hand washing makes symptoms worse. While emotional stress may make the symptoms worse
commonly make it worse include wool clothing, soaps, perfumes, chlorine, dust, and cigarette smoke
UV radiation targets inflammatory cells on the skin, inducing positive immunosuppressive effects by altering cytokine production, inducing apoptosis of infiltrating T-cells, and by inhibiting the antigen-presenting function of Langerhans cells. UV radiation can protect the skin by inducing thickening of the stratum corneum which could limit eczematous reactions and prevent entry of external antigens.Finally, skin colonization by Staphylococcus aureus and Pityrosporum orbiculare may be prevented or reduced by the antibacterial effect of UV radiation
Mechanism of action. Clotrimazole works to kill individual Candida or fungal cells by altering the permeability of the fungal cell wall. It binds to phospholipids in the cell membrane and inhibits the biosynthesis of ergosterol and other sterols required for cell membrane production.
Malassezia furfuris responsible for a small number of cases.These yeasts are normally found on the human skin and become troublesome only under certain circumstances, such as a warm and humid environment, although the exact conditions that cause initiation of the disease process are poorly understood.- production of azelaic acid, which has a slight bleaching effect
Tine capitis – the fungus invades the hair follicle
An exanthem is any eruptive skin rash that may be associated with fever or other systemic symptoms. Causes include infectious pathogens, medication reactions and, occasionally, a combination of both.
Over 100 years ago, a group of characteristic childhood eruptions were described and numbered from one to six:[1,2] measles, scarlet fever, rubella, erythema infectiosum and roseola infantum. The origin of the fourth classic childhood eruption, formerly referred to as Dukes' disease, is controversial. It may represent misdiagnosed cases of rubella or scarlet fever, rather than a distinct illness.
Koplik spots appear next to the premolar 2 days before the exanthem
Morbifiliform rash starts after 3 days on face and behind ears then spreads to trunk
Maculopapular rash
Forscheimer's spots on uvula
Hallmark = generalized tender lymphadenopathy which involves all nodes, but which is most striking in the suboccipital, postauricular, and anterior and posterior cervical nodes
small red bumps that begin on the neck and groin
Rash peels
cheeks appears red and flushed
dark, hyperpigmented areas on the skin, especially in skin creases. These areas are called Pastia's lines
Non-suppurative:
(The antibodies which the person’s immune system developed to attack the group A streptococci are in these cases also able to attack the person's own tissues.) Type 2 hypersestivity)
Jones criteria for Rheumatic fever: migrating arthritis, carditis, syndenhams chorea, erythema marginatum and subcut nodules
Slapped cheek
Parvovirus infection in pregnant women is associated with hydrops foetalis due to severe foetal anaemia
term exanthem subitum describes the sudden "surprise" appearance of the rash after the fall of the fever
Rash fades in hours -> 2 days
Rare complications. Usually just febrile convulsions
- Caused by Human Herpes Virus 6 (HHV-6)
EM minor is regarded as being triggered by HSV in almost all cases. A herpetic aetiology also accounts for 55% of cases of EM major. Among the other infections, Mycoplasma infection appears to be a common cause.
Herpes simplex virus suppression and even prophylaxis (with acyclovir) has been shown to prevent recurrent erythema multiforme eruption
The drug or metabolite covalently binds with a host protein to form a non-self, drug-related epitope. An antigen presenting cell takes up these alter proteins; digests them into small peptides; places the peptides in a groove on the human leukocyte antigen component of their major histocompatibility complex and presents the MHC-associated peptides to T-cell receptors on CD8+ T cells or CD4+ T cells.