Professor Alison M Kesson Infectious Diseases and Microbiology Approach to Diagnosis
• This is not easy !!! • Rash may or may not be diagnostic • Will need history, physical exam and investigations • HISTORY – Prior infectious diseases – Immunisations – Travel – Prodromal illness – Contacts Approach to Diagnosis
• PHYSICAL EXAM – General state – Temperature – Conjuctiva – Ears and throat – Auscultation of chest – Abdomen – liver and spleen – Lymph nodes Types of rashes
• Vesicles and Bullae • Purpura and ecchymoses • Macular • Papules • Urticaria • Erthema multifomae • Erythema nodosum Vesicles and Bullae Vescicles
• Result from a disturbance of cohesion of epidermal cells or components of a basement membrane zone associated with influx of fluid into or beneath the site of disturbance.
• Vesicles < 1cm; bullae > 1cm
• Rapidly evolve into erosions, ulcers or crusts.
• Most are benign, others are rapidly progressive and life threatening. Vesicular rashes
• VZV • HSV • Enterovirus – hand foot and mouth disease • Impetigo • Contact dermatitis • Pemphigus • Pemphigoid • Incontinentia pigmenti • Epidermolysis bullosa • Burns • Drugs • Allergies Vesicular rashes
• Solitary – lesions of streptococcal blistering dactylitis • Localised – staphylococcus bullous impetigo • Grouped or clustered – herpes simples virus infection • Arranged linearly – shingles - Varicella zoster virus • Generalised – chickenpox - varicella. Herpes simplex Herpes simplex www.flickr.com/photos/nojhan/472561609/
Chickenpox
www.doctorhagen.com/Chicken.htm
www.flickr.com/photos/nojhan/472561609/ Herpes zoster Herpes zoster Hand Foot and Mouth Disease
www.primehealthchannel.com/hand-foot-and-mout... hardinmd.lib.uiowa.edu/.../handfootmouth.html Herpangina Bullae
• Staphylococcal scalded skin syndrome -SSSS
• Erythema multiforme (with HSV infection)
• The appearance of bullae caused by thermal injury or hypersensitivity response to insect bite are identical to that of bullous impetigo. Haemorrhagic bullae
• May accompany septicaemia caused by gram negative organisms – Ps. aeruginosa (ecthyma grangrenosum) • Neisseria meningitides • necrotising soft tissue infections due to Streptococcus pyogenes. Erythematous Macules and Papules Maculopapular rashes
• Erythematous macules and papules are the most common primary lesions seen during acute febrile illness in children. • Almost all viral and many bacterial exanthems that occur in the first year of life are of this type, and many conditions that ultimately manifest purpuric, vesicular, urticarial or ulcerative cutaneous lesions first appear as erythematous macules or papules. • Most are brief, self-limiting, and uncomplicated. Definitions
• Macules – circumscribes, flat, discoloured, not palpable, erythematous or purpuric. • Patch if > 1 cm • Papules – circumscribed, solid, elevated, < 1cm. • Plaques – elevated, flat top, > 1cm History • 1. age • 2. season • 3. exposure to toxins or medications • 4. exposure to an ill person • 5. geographic location and travel • 6. immunization history • 7. history of previous illness • 8. exposure to domestic or wild animals • 9. pattern of evolution of the rash • 10. associated symptoms and signs Pathogenesis
1. infection of cells of epidermis, dermis or vascular endothelium
2. host immunological reaction to infecting organism
3. circulating toxins
4. a combination of above. Maculopapular rashes
• Measles • Rubella • Scarlet fever • Kawasaki disease • Erythema infectiosum-5th disease-Parvovirus B19 • Roseola infantum-6th disease-HHV-6 • Viral infection esp. enteroviruses - most common • Epstein Barr virus infection www.primehealthchannel.com/hand-foot-and-mout...
Measles
CDC CDC Measles
CDC CDC Rubella
CDC CDC Parvovirus B19
CDC CDC barbraschroeder.com/muhanadoela/scarlet-fever... barbraschroeder.com/muhanadoela/scarlet-fever... www.thesun.co.uk/sol/homepage/woman/health/he...
Scarlet Fever
barbraschroeder.com/muhanadoela/scarlet-fever...
www.thesun.co.uk/sol/homepage/woman/health/he... Kawasaki disease
ep.bmj.com/content/89/1/ep3.full thejez256.wordpress.com/.../ Purpura Purpura
• association with life threatening infections from multiple causes. • vascular injury or disorders of haemostasis associated with platelet depletion or dysfunction. Purpura
• Purpura is sub divided into three forms on the basis of size, depth and extent of haemorrhage – petechiae – ecchymosis – palpable purpura Purpura • Petechiae are purpuric macules < 2mm • extravasation of blood from capillaries, often appear over a short time in crops or showers. • Isolated petechiae are a common finding in early blood stream infection. • Lesions that blanch under pressure are not extravascular blood. • Ecchymosis – all bruises are areas of bleeding into the skin that differ from petechiae only by their larger size. • Purpura fulminans – Neisseria meningitides, or varicella zoster virus, • large confluent purpuric patches, subsequently undergo necrosis and scar formations. Petechiae • 60% have presumed or proven viral illness, approximately • 20% had invasive potential life threatening bacterial disease, most commonly septicaemia with or without meningitis • 20% had a variety of other infectious and non- infectious conditions. • Viruses generally cause vasculitis involving small vessel, whereas bacteria tend to invade vessels of a variety of sizes. Ecchymosis
• Rare in infection • Consider trauma and child abuse Purpura
• Purpuric rash is caused by vasculitis (e.g, Henoch- Schonlein purpura) or defects in clotting factors. • • Purpura fulminans and symmetrical peripheral gangrene association with relatively benign infections such as varicella or S. pyogenes. • Congenital or acquired protein C or protein S or anti- thrombin 3 deficiency may cause a similar clinical picture. Purpura
• Palpable purpura – small vessel vasculitis – meningococcus – staphylococcus – gonococcus • Immune mediated vasculitis – hepatitis B virus – atypical measles – chronic meningoccaemia – bacterial endocarditis. Blueberry muffin rash
• Blueberry muffin rash - papable
• intradermal haemopoietic tissue
• congenital rubella Petechiae and purpuric rashes • Enteroviruses • Meningococcal infection • Henoch-Schonlein purpura • Idiopathic thrombocytopenic purpura • Leukaemia www.australianprescriber.com/magazine/22/5/117/8/
Purpura - menigococcus
https://www.umm.edu/imagepages/2884.htm www.australianprescriber.com/magazine/22/5/117/8/ Meningococcus Urticaria Urticaria
• Urticaria is a common problem. • Sudden onset of circumscribed erythematous, oedematous papules or plaques often showing central clearance. • A few millimetres to centimetres in bizarre irregular shapes. • Papular urticaria is a reaction to an arthropod bite. Urticaria
www.nlm.nih.gov/.../ency/imagepages/2482.htm irasyafira.blogspot.com/2010/07/urticaria.html Urticaria • 50%of urticaria associated with infections - Strep pyogenes is most common. • Associated virus infections – adenovirus, – coxsachie viruses, A9, A16, B4, B5, – echo virus 11, – Epstein Barr virus, – hepatitis viruses A, B, C, – human immunodeficiency virus, – measles virus, – mumps Urticaria
• Viral upper respiratory tract and gastrointestinal tract infections are the primary infectious triggers of acute urticaria in children. • Urticaria can also occur in association with – mycoplasma, – treponemal, – rickettsial – fungal – parasitic • Kawasaki disease or in association with infestation or bites of arthropods. Erythema multiforme Erythema multiforme
• Numerous manifestations in the skin from erythematous macules, papules, vesicles, bullae or urticarial plaques to patches of confluent erythema.
• Diagnosis is established by finding donut shaped target lesions(iris or bullseye), with an erythematous outer border and inner pale ring and an erythematous centre. Erythema multiforme
• HSV has been implicated in at least 60% of episodes, and trigger nearly all episodes of recurrent disease. • HSV antigens and DNA are present in skin lesions. • Mycoplasma pneumoniae associated with Steven Johnson syndrome, organism detected in skin lesions. • Stevens Johnson syndrome is characterised by lesions that develop predominately on the extremities, accompanied by involvement of 2 or more mucosal surfaces. Erythema multiforme
www.justanswer.com/medical/2iegk-11-year-old-... www.wrongdiagnosis.com/.../4652.html Stevens Johnson syndrome Papules, nodules and ulcers. Papules and nodules
• A papule is a raised superficial lesion that is less than 1cm in size. • A nodule is a solid palpable lesion greater than 1cm in size. Molluscum Contagiosum
• Molluscum Contagiosum produces a papule in skin cause largely by the presence of virions. • Pox virus replicates in the cytoplasm of host epithelial cells. • Acquired through direct contact with an infected person or from fomites and is spread by auto inoculation. • Incubation periods is estimated to be 2-8 weeks or longer. • Discreet pearly skin coloured dome shaped smooth papule 1- 5mm, central umbilication, a plug of cheesy material can be expressed, occur anywhere on the body, predilection for face, eyelids, neck, axillae, thighs. Molluscum Contagiosum
mummahh.blogspot.com/2011/02/molluscum-contag... Erythema nodosum Erythema nodosum
• Sudden appearance of exquisitely tender erythematous 1-10 cm nodules usually extensor surface of leg. • Lesions can develop on calves, thighs, trunk, upper limbs, head and neck. • Rare in children , 2 years – adolescence. • Nodules enlarge over 2-3 days stabilise for 03 weeks then resolve over 3-6 weeks leaving hyperpigmentaion – slow resolution. Erythema nodosum
• Associated with – Group A streptococcus (Strep. pyogenes) infection – Tuberculosis – Yersinia enterocolitica – Bartonella henselae (cat scratch disease) – Drugs – sulphonamides – Sarcoid – Malignancy – leukaemia and lymphoma – Behcet’s, Reiter’s, SLE, IBD. Erythema nodosum
www.healthopedia.com/.../erythema-nodosum.html
http://www.empowher.com/condition/erythema-nodosum Erythema nodosum
www.skinsight.com/adult/erythemaNodosum.htm
http://www.cmaj.ca/cgi/content/full/178/2/151/F218 • “Alison, when you know what is causing the infection, you will know what is causing the rash”.
• Prof James D. Cherry UCLA1990 Thank You
Questions