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| - | ===Bright Red Rashes===
| + | FjKUEn Thanks for the article post.Really looking forward to read more. Want more. |
| - | *There are five primary players in bright red rashes:
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| - | **Urticaria
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| - | **Erythema multiforme
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| - | **Morbilliform eruptions
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| - | **Lupus erythematosus
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| - | **Dermatomyositis
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| - | ====General tendencies====
| + | |
| - | *In general, vascular reactions to insult can be described by color, topography, and time course:
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| - | **Color: redness = erythema, results from excessive blood flow
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| - | **Topography: raised lesions result from edmea
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| - | **Time course: a reaction can be described as dynamic = evanescent
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| - | ***Note that evanescent means "soon passing out of sight or memory"
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| - | *These three classic vascular reactions ('''erythema, edema, and evanescent''') best describe urticaria, erythema multiforme, and morbilliform reactions
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| - | ====Urticaria====
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| - | *Urticaria is an '''allergic reaction''' that results in a bright red rash.
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| - | *Urticaria is colloquially known as "hives"
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| - | **The offending '''antigen is usually from a virus, a food, or a drug'''
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| - | **Physical factors can also induce urticaria (think "SPACE"): sun exposure, pressure, aquagenic, cold, exercise
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| - | *Pathogenesis of urticaria:
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| - | **Induction of immune response results in a dilated (erythema), leaky (edema) vascular state that can be readily changed (evanescent)
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| - | **Urticaria's EEE state is '''primarily driven by histamine''' acting on small dermal vessels
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| - | **'''Purpura can result if''' immune complexes damage endothelium to the extent that '''RBCs escape into the tissue'''
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| - | ***Purpura generally lasts more than 24 hours at a single location
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| - | *The rash of urticaria is often described as being '''annular'''.
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| - | *Hives come and go very quickly
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| - | *Hives can be ''annular''
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| - | *Tricyclics can be used in chronic urticaria when it is affecting the pt's mood
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| - | *http://www.urticare.com/site/urticare/images/basic_theme/back.gif
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| - | *http://images.paraorkut.com/img/health/images/u/urticaria-1944.jpg
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| - | *http://images.ddccdn.com/enc/images/images/en/hives-urticaria-close-up-1651.jpg
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| - | *http://www.rash-pictures.com/images/4/488.jpg
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| - | ====Erythema Multiforme====
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| - | *Erythema multiforme is an '''allergic reaction''' that results in a bright red rash.
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| - | **Note that both urticaria and EM are allergic reactions.
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| - | *Erythema multiforme is distinct from urticaria by its '''immune complexes''' and its '''apoptotic cytotoxic T cells'''.
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| - | *Erythema multiforme is classified as minor and major based on how severe the manifestation.
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| - | **'''EM minor is usually caused by herpes simplex virus''', especially when EM is recurrent.
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| - | **'''EM major is usually caused by drugs'''
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| - | *EM Major has several named causes / syndromes: '''Stevens-Johnson syndrome''' and '''Toxic Epidermal Necrolysis'''
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| - | **Both SJS and TEN are (usually) allergic reactions to drugs that result in necrolysis of keratinocytes of the lower epidermis.
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| - | **Some consider TEN a more severe form or SJS.
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| - | *EM presentation:
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| - | **Target lesions on palms
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| - | **Oral mucosal involvement
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| - | **http://medicalimages.allrefer.com/large/erythema-multiforme-target-lesions-on-the-palm.jpg
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| - | **http://im.unboundmedicine.com/medicine/ub/image?na=app:16010:ch18_8.bmp
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| - | **http://www.ebmedicine.net/media_library/aboutUs/Erythema%20Multiforme%20Pediactric%20Emergency%20Medicine%20Practice.JPG
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| - | **http://www.dermatopedia.com/wp-content/themes/dermatopedia/dermimages/4774_Erythema_Multiforme.jpg
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| - | **http://www.dermweb.com/hairnailsmucousmembranes/graphics/jpegs/Untitled-8a.jpg
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| - | **http://www.acponline.org/graphics/bioterro/e_minor.jpg
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| - | *Stevens-Johnson Syndrome images:
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| - | **SJS presents with '''widespread "targetoid" lesions'''
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| - | **Can have severe ocular involvement: sclerosis of cornea
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| - | **It's like a burn, so we're worried about sepsis and Na-hydration issues.
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| - | ***Note that these targetoid lesions are different than the target lesions in classical EM presentation
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| - | **http://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Clinical%20Images/Stevens_Johnson-28.jpg
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| - | **http://www.nursinghomesabuseblog.com/uploads/image/Picture%2023.png
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| - | **http://rad.usuhs.mil/derm/lecture_notes/Images/Stevens_Johnson.JPG
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| - | **http://img.medscape.com/fullsize/migrated/565/823/edm565823.fig2.jpg
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| - | **http://www.joeway.co.uk/images/stevenjohnsons2.jpg
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| - | =====Target lesions versus Targe''toid'' lesions=====
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| - | *Target lesions:
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| - | **Have '''concentric circles''', especially when there are three concentric circles
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| - | **Have central duskiness or a central blister
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| - | **Have a relatively wide pale circle in between
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| - | **Have an outer, thin, moderately erythematous circle
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| - | **http://www.aic.cuhk.edu.hk/web8/0024_erythema_multiforme.JPG
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| - | **http://dermgunner.com/wp-content/uploads/2010/09/target_lesions_of_erythema_multiforme.jpg
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| - | **http://images.medicinenet.com/images/image_collection/skin/erythema-multiforme-minor.jpg
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| - | **http://drugster.info/img/ail/2957_2979_1.JPG
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| - | **http://drugster.info/img/ail/2957_2979_3.jpg
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| - | **http://www.meddean.luc.edu/lumen/MedEd/medicine/dermatology/melton/erthmul1.jpg
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| - | *Targetoid lesions:
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| - | **Suggest zonality '''but don't have 3 distinct concentric circles'''
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| - | **In general, ''targetoid lesions are more serious than target lesions''.
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| - | **http://upload.wikimedia.org/wikipedia/commons/thumb/6/68/EMminor09.JPG/230px-EMminor09.JPG
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| - | **http://dermnetnz.org/reactions/img/ermulti1-s.jpg
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| - | **http://dermatology.cdlib.org/1508/articles/2008102101/1.jpg
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| - | ====Morbilliform Reactions====
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| - | *Morbilliform reaction is '''through to be a T-cell mediated hypersensitivity''' to drugs or pathogens.
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| - | *Etiology can be drugs or pathogens
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| - | **Many different drugs (including antibiotics) can cause morbilliform reactions
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| - | **Many pathogens can cause morbilliform reactions; usually enterovirus or group A streptococcus
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| - | *One diagnosis the etiology by culturing the "company" kept by the rash
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| - | *Morbilliform reaction manifests same symptoms regardless of causative agent
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| - | *Morbilliform reaction is '''less evanescent''' than multifomre erythema and urticaria
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| - | *Morbilliform reaction is characterized by '''truncal predominance'''
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| - | **Recall that urticaria could show up anywhere and multiform erythema usually involved the oral mucosa and palms of the hands
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| - | *Morbilliform is marked by its '''maculopapular rash'''
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| - | **Recall that a [http://editthis.info/iusmicm/Dermatology_-_Introduction#Macule_.2F_Patch macule] is NOT raised but is discolored and that a [http://editthis.info/iusmicm/Dermatology_-_Introduction#Papule_.2F_Plaque papule] IS raised but not necessarily discolored.
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| - | ***http://www.aafp.org/afp/20000815/804_f1.jpg
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| - | ***http://eso-cdn.bestpractice.bmj.com/best-practice/images/bp/en-gb/774-2_default.jpg
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| - | =====Viral Exanthems=====
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| - | *Most viral exanthems manifest as ''morbilliform reactions'' ('''except for varicella''').
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| - | **Recall that an exanthem is a skin eruption secondary to systemic disease.
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| - | **Recall that varicella is a viral infection with herpes.
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| - | *Recall the viral agents that cause the classic pediatric exanthems:
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| - | **'''These all cause MORBILLIFORM reactions'''
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| - | **Rubeola (Measles, paramyxovirus infection) (four Cs): '''c'''ough, '''c'''oryza (watery eyes), '''c'''onjunctivitis, '''k'''oplik spots
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| - | ***Rubeola is a systemic infection by paramyxovirus of the genus Morbillivirus
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| - | **Rubella (German Measles, rubella virus infection): 3 day progression, progresses toward cephalocaudal poles
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| - | **Roseola (Roseola Infantum, roseola virus infection): fever, followed with '''rash when "defervesce"'''
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| - | **Mononucleosis (3 Fs): '''f'''ever, '''f'''atigue, '''(f)ph'''aryngitis, adenopathy, liver / spleen involvement
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| - | ***Kissing disease
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| - | **Fifth disease (Erythema infectiosum): slapped cheeks, fishnet erythema, recurrence
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| - | ***An example of "multiple stages" seen in many viral exanthems
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| - | *Viral exanthums are characterized by: "dew drop on rose petal" formation, umbilicated vesicles, and multiple stages:
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| - | **http://dermnetnz.org/img/umbilicated-s.jpg
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| - | **http://www.elsevierimages.com/images/vpv/000/000/037/37056-0550x0475.jpg
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| - | **http://203.64.79.70/DERMATOLOGY/fac/img0023.jpg
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| - | ====Lupus Erythematous====
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| - | *Lupus erythematous is an autoimmine disease
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| - | *There are three types of lupus: systemic (SLE), discoid (DLE), and subacute cutaneous (SCLE)
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| - | **Systemic and subacute cutaneous can be '''induced by drugs'''
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| - | *'''All three types of SLE are considered ''idiopathic'''''.
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| - | **A genetic predisposition has been demonstrated.
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| - | *SLE (systemic lupus erythematous) requires 4 of 11 ARA criteria be met.
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| - | *DLE (discoid lupus erythematous) is '''primarily cutaneous''' in manifestation.
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| - | *SCLE (subacute cutaneous lupus erythematous); subacute means it is not quite acute or chronic.
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| - | *Pathogenesis of lupus eyrthmatous is though to be '''UV radiation induced'' and involves formation of '''immune complexes'''.
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| - | =====Systemic lupus erythematous=====
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| - | *Systemic lupus erythematous has 11 diagnostic criteria that can be divided into '''skin and mucus''', '''systemic''', and '''laboratory''' findings.
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| - | **To diagnose SLE, you must "'''DUMP the SAC on the RAC'''"
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| - | *Skin and mucosal criteria (DUMP):
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| - | **Discoid lupus
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| - | **Ulcers (oropharyngela, usually painless)
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| - | **Malar rash
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| - | **Photosensitivity
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| - | *Systemic criteria (SAC):
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| - | **Serositis (pleural, pericardial): inflammation of the serous tissues--things that line the lungs / heart (pleura, pericardium)
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| - | **Arthritis
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| - | **CNS (seizures, psychosis)
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| - | *Laboratory criteria (RAC)
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| - | **Renal dysfunction (Urinary analysis, elevated 24-hour urine protein levels)
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| - | **Antinuclear antibodies (or others like anti-dsDNA or anti-Smith)
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| - | **CBC (Hematology)
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| - | *'''DUMP the SAC on the RAC''' (skin / mucosa, systemic, lab)
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| - | *Systemic lupus erythematous presents with a '''malar rash''' and '''photosensitivity'''
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| - | **There is sometimes "spillover" to unexposed sites, too, with the photosensitivity.
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| - | *SLE can manifest '''[http://editthis.info/iusmicm/Dermatology_-_Hair_Disorders#Scarring_alopecia scarring alopecia]'''
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| - | ====Dermatomyositis====
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| - | *Dermatomyositis is an inflammation of the skin and muscle.
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| - | **Note that polymyositis is inflammation of the muscle with neurological signs but ''with no skin features''.
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| - | *Like lupus erythematous, '''most dermatomyositis cases are idiopathic'''.
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| - | **'''A small subset of dermatomyositis are drug-induced'''.
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| - | *There is a definite role of '''UV radition in inducing dermatomyositis'''
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| - | *Dermatomyositis is characterized by '''involvement of the complement systems membrane attack complex (MAC)'''
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| - | *Note that '''dermatomyocytis is on the IP joints of the fingers but lupus is NOT on the knuckles'''
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| - | *Diagnostic criteria for dermatomyositis:
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| - | **Not all 5 are required
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| - | **Skin features (to differentiate it from polymyositis)
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| - | **'''Proximal muscle weakness''' which is usually painless
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| - | **''Muscle enzyme abnormalities'' (identified with CPK and aldolase levels)
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| - | ***CPK: creatine phosphokinase; adds kinase to creatinin; MM isoform in skeletal muscle, MB isoform in cardiac muscle, BB in smooth muscle
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| - | **'''EMG abnormalities'''
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| - | **Muscle biopsy
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| - | **(currently we use MRI to dx, too)
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| - | *Dermatomyositis presentation:
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| - | **Heliotrope rash (upper eyelids)
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| - | **Photosensitivity with spillover
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| - | **Poikiloderma: see next section
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| - | **Gottron's papules (area between knuckles is spared)
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| - | **Periungual telangiectasias
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| - | *Heliotrope rash (upper eyelids):
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| - | **http://www.learn2grow.com/gardeningguides/seasonalgardening/summer/~/media/articles/2008/05/16/HeliotropeFlowerCloseup_225x171.ashx
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| - | **http://www.botany.wisc.edu/garden/UW-Botanical_Garden/garden_Images/Heliotropium_arborescens_sm.jpg
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| - | **http://media.growsonyou.com/photos/products/2157.jpg
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| - | **http://www.healthsci.jmu.edu/common/Knitter/Graphics/dermatology/heliotrope%20rash.jpg
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| - | **http://www.healthsci.jmu.edu/common/Knitter/Graphics/dermatology/heliotrope%20rash%20II.jpg
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| - | **http://1.bp.blogspot.com/_xzqs4DHM8as/TGroqfIXVSI/AAAAAAAAACg/LvH4C2NjkRs/s320/Heliotrope.jpg
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| - | *Photosensitivity with spillover:
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| - | **http://www.dermaamin.com/site/images/clinical-pic/p/photosensitivity/photosensitivity17.jpg
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| - | **http://www.healthline.com/images/gale/big/gem_04_img0508.jpg
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| - | **http://www.siamhealth.net/public_html/Health/picture/photosensitivity.jpg
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| - | *Poikiloderma: see next section
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| - | *Gottron's papules (area between knuckles is spared):
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| - | **http://imaging.ubmmedica.com/consultantlive/images/articles/2003/07012003/0307ConPERheum2B.jpg
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| - | **http://www.aocd.org/images_ddd/Dermatomyositis_Gottrons_papules_1_low.jpg
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| - | **http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/1866.jpg
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| - | **http://www.curejm.com/symptoms/symptom_gottron1.jpg
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| - | **http://img.medscape.com/pi/features/slideshow-slide/cmsd/fig13.jpg
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| - | *Periungual telangiectasias:
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| - | **http://upload.wikimedia.org/wikipedia/commons/8/82/Dermatomyositis6.jpg
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| - | **http://images.rheumatology.org/image_dir/album75693/md_99-06-0061.tif.jpg
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| - | **http://dermatology.cdlib.org/1502/reviews/photoessay/56.jpg
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| - | =====Poikiloderma=====
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| - | *Poikiloderma is characterized by '''hyperpigmentation, hypopigmentation, telangiectasias, and / or atrophy'''.
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| - | *Poikiloderma is seen in conjunction with '''dermatomyositis, UV radiation damage, and ionizing radiation damage'''.
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| - | *http://www.skinsight.com/images/dx/webAdult/poikilodermaofCivatte_11790_lg.jpg
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| - | *http://www.skincareguide.ca/images/glossary/poikiloderma.jpg
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| - | *http://www.aocd.org/images_ddd/Poikiloderma_1_low.jpg
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| - | *http://www.laserskinsurgery.com/img/Poikiloderma-After.jpg
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| - | *http://www.dermatopedia.com/wp-content/themes/dermatopedia/dermimages/2266_poikiloderma_of_civatte.jpg
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| - | *http://somalaser.com/blog/wp-content/uploads/2011/01/vbmBA2lrg.jpg
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| - | *http://www.doctorv.ca/images/services/light-treatments/ipl_fotofacial_skin_rejuvenation/large_poikiloderma_sun_damage.jpg
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| - | *http://www.danderm-pdv.is.kkh.dk/atlas/pics/3/3-49-4.jpg
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| - | *http://www.riversideonline.com/source/images/slideshow/sn22_poikiloderma.jpg
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| - | *http://www.slievemore1.com/images/cosmetic%20images/ipl7.jpg
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| - | ====Drug reactions====
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| - | *Drug reactions '''can generate every possible different cutaneous pattern'''
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| - | *Rarely does clinical presentation afford enough information to dx drug-induced reaction
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| - | **Usually requires additional information like lab values
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| - | *'''Some patterns caused by drug reactions are considered higher risk'''
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| - | **These patterns have significant morbidity or have mortality associated with them
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| - | **'''High risk patterns include''': urticaria / anaphylaxis, erythema multiforme major (SJS, TEN), morbilliform reactions (with hypersensitive syndrome characteristics), and '''vasculitis'''
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| - | *All the rest of the patterns are relatively low risk for morbidity and mortality.
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| - | | + | |
| - | =====An algorithm for diagnosing drug-induced cutaneous reactions=====
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| - | *The process is, in general, a series of controlled challenges to the pt with the drug: challenge, dechallenge, rechallenge, exlusion
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| - | *First we challenge with the drug
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| - | **An important aspect to the challenge is the time of drug administration
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| - | **This should be informed by the literature and one's own experience with the drug
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| - | *Then we "dechallenge"
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| - | **We watch for cessation of the drug reaction
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| - | **Dechallenging is options, unless the drug is essential for the pt's life
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| - | **Dechallenging will not result in cessation of recation if the reaction is irreversible
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| - | *Next we rechallenge
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| - | **This repetition gives the highest level of certainty that the reaction is drug-induced
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| - | **Rechallenging is optional
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| - | ***Rechallenge is not an option if the challenge resulted in a higher-risk reaction pattern (which would advise no rechallenge for safety reasons)
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| - | ***Rechallenge is not an options if there is an alternative therapy to the drug that causes a reaction (because we shouldn't give a drug we know causes an adverse reaction is there is still another potentially non-reactive drug available)
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| - | *Finally we exclude
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| - | **If the dechallenge does not generate cessation or if the rechallenge does not cause the same reaction the we exclude drug-induced reactions from the ddx.
| + | |
FjKUEn Thanks for the article post.Really looking forward to read more. Want more.
