Derm wk 4 Flashcards
Most skin drug reactions are
Inflammatory
Generalized
Symmetric
Immediate drug reactions
occur within 1 hour!
Urticaria (hives), Angioedema, Anaphylaxis
Delayed drug reactions
Often occur after 6 hours, sometimes even weeks- months after starting med
Exanthematous, Fixed drug eruption, Systemic (DIHS, SJS/TEN), Vasculitis
Most of the time, allergy testing is useless for med reactions, BESIDES with
PCN
PCN skin testing is preferred when evaluating possible type I, IgE mediated PCN allergy
Test for PCN allergy
PCN skin testing
look for IgE mediated PCN allergy
Risk factors for drug rxns
Female Prior drug rxn Recurrent drug exposure HLA gene Certain dz states- Mono or HIV positive
HIV positive often have dermatologic rxns to
Sulfa
Drug timeline
Onset of rash as day 0, then work backwards and forwards
Widespread, symmetric
Confluent erythematous macules and papules on trunk and extremities, AKA
“Morbilliform” measles-like eruption
macule
circumscribed, FLAT, discoloration that is <10 mm
Most common skin drug eruption
Exanthematous Drug Eruption
Details on Exanthematous Drug Eruption
Limited to Skin
Red macules and papules starting on the TRUNK and spread centrifugally to the arms/legs in symmetric fashion
What might be present along with the Exanthematous Drug Eruption classic mac-pap rash?
Mild fever
Itchiness
Rash starts 7-10 days after drug if 1st time, and 1-2 days after drug if recurrent
Papules
small also, <10 mm
but RAISED
Can you keep taking the drug if you get an Exanth Drug Eruption rash?
Yes but only if eruption is not severe and med can’t be subbed
How soon does Exanth Drug Erup last after stopping the med?
Clears up in a few days- week after med is stopped
Tx for Exanth Drug Eruption rash
Topical steroids
Oral antihistamine
Reassurance
Oral erythematous plaque with central bulla
Fixed drug eruption
FDE- Fixed drug eruption
Formation of one or more round or oval patches or plaques that recur at same site with re-exposure to the drug
Common culprits of FDE- fixed drug eruption
Laxatives Tetracyclines Metro Sulfa Barbs NSAIDs Salicyates (ASA) Food coloring
Where do FDE often occur?
Mouth, genitalia, face, fingers, toes
but can occur anywhere
How quickly do FDE show up?
In prev sensitized ppl, as soon as 30 min- 8 hours after taking drug
Early lesions of FDE are sharply demarcated red macules (flat) —->
become raised, forming plaques, which may –> bullae then erosions
In the healing phase, lesions from FDE
violet hue followed by post inflammatory hyperpigmentation
Tx for FDE
Non-eroded: Potent topical steroid ointment
Eroded: Protective or antimicrobial ointment + dressing
Pt presents with combo of:
Rash + Facial edema
suspect drug rxn with Eosinophilia and Systemic sx
DRESS
If you suspect DRESS, what next
Order CBC- look for Eisinophilia, and LFT and Renal(kidney) fx test to evaluate for end organ damage
Normal platelet count
150-450
Normal Hematocrit
36-48%
Drug Induced Hypersensitivity Syndrome (DIHS) is AKA
DRESS- Drug Rxn w Eisinophilia and Systemic Sx
Skin eruption with systemic sx and internal organ involvement (Liver, Kidney, Heart)
DRESS
or
DIHS
Typical signs of DRESS or DIHS
Rash, red centrofacial swelling, fever, malaise, lymphadenopathy, involvement of other organs
Most pts experiencing DRESS/DIHS have what on labs
Eosinophilia
> 70% have this
How long does it take for DIHS/DRESS sx to occur?
in the 3rd week (but range 1-12 weeks) after starting the medication
Sx can persist and recur for many weeks after stopping drug
What is fatality rate for DRESS/DIHS?
up to 10%
Common meds causing DIHS/DRESS
Allopurinol Abx- Sulfa, PCN, Mino, Metro AntiTB- Isoniazid Anticonvulsant- Phenytoin, Carbamazepine, Lamotrigine NSAIDs Anti-HIV- Abacavir
Approach to pt with suspected DIHS
Stop (or sub) all culprit meds and discontinue non-essential meds
Tx for DIHS
mild: topical steroids + systemic antihistamines
severe: systemic steroids (prednisone) and taper gradually weeks- months
severely ill: ICU
“Sloughing rash”
On Sulfa and Bactrim for UTI
SJS/TEN!!
Widespread erosions on face, upper trunk, and arms
Begin as painful flaccid blisters
How do SJS and TEN differ?
BSA- % body surface area that is involved
Mortality rate of SJS
5-12 %
Mortality rate of TEN
> 20%
worse!
SATANN is a mnemonic to help remember common meds that can cause SJS/TEN!
Sulfa Allopurinol Tetra, thiacetazone Anticonvulsant NSAIDs Nevirapine
What precedes the rash of SJS/TEN?
Fever
HA
Runny nose
Myalgias by 1-3 days
How soon after taking med does SJS/TEN start?
within 8 wks after drug initiation
Red, irregularly shaped, dusky red to purple macules,
that progressively coalesce
SJS/TEN rash description
Dark center of atypical target lesion may blister
SJS/TEN
Classifying SJS/TEN
SJS <10 % BSA
SJS/TEN 10-30%
TEN >30%
Mucous membrane involvement associated with SJS/TEN
Red –> painful erosions of the buccal, ocular, and genital mucosa
Mouth, Eyes, Genitals
Whats the worst part of Eye involvement with SJS/TEN
Many will suffer permanent Eye sequelae, even blindness
SJS/ TEN complications
Eye damage Oral cavity sicca synd and pain GU damage Pulmonary- bronchitis, bronchiectasis Fluid/electrolyte disturbance Nutrition requirements Secondary INFECTION
SJS/TEN Tx
consult Dermatology and Ophthalmology
Burn unit
IV steroids, IVIG, Cyclosporine, or Etanercept are given variable at diff centers
Prevention of SJS/TEN
FDA recommends
Test for HLA-B 1502 for all pts SOUTHEAST ASAIN starting Carbamaz
Test for HLA-B 5701 for ALL PTS starting Abacavir
Another gene association
HLA-B 5801 genetic screening for some Southeast Asain, Japanese, European patients starting Allopurinol
Genes and associations
HLA 1502: Carbamazepine
HLA 5701: Abacavir
HLA 5801: Allopurinol
1502
Carbamazepine
5701
Abacavir
5801
Allopurinol
Cardinal sx of Urticaria
Pruritis
Urticaria is caused by
swelling of the upper dermis
Angioedema
Same mechanism as hives, but in the DEEP DERMIS and SUBQ
swelling is the major manifestation
Angioedema and/or Urticaria can be the ________ of Anaphylaxis
Skin portion
assessment of the Respiratory and Cardiovascular sx are vital!
Course of hives
Appear within minutes, enlarge, and then disappear in hours
Rarely last longer than 12 hours
Urticaria can be Acute or Chronic
Acute: <6 weeks
Chronic: recurrent more than 2 days per week longer than 6 weeks
Common cause of Acute Urticaria
Idiopathic Infection- URI, strep, worms Food- shellfish, nuts, fruit Drug rxns IV products- contrast or blood products
Cholinergic Urticaria
triggered by heat and emotion
Dermatographism
most common form of physical urticaria- sharply localized edema/wheal within seconds-min of skin being rubbed
Urticaria Multiforme
Kiddos
Polycyclic or Annular lesions with dusky and ecchymotic centers along with acral edema (fingers and toes= acral)
Urticaria Multiforme
improves w Antihistamines
Immunologic urticaria
related to IgE
Antigen binds to IgE on the mast cell causing degranulation and release of Histamine
Non-Immunologic urticaria
not dependent on the binding of IgE receptors
i.e. ASA induced hives
Diffuse red papules coalescing into plaques
Wheals
Is lab testing required for ACUTE Urticaria?
No
Common causes of hives via the IgE mediated mechanism
PCN
Other Abx
Common cause of NON-IgE mediated mechanism
ASA
30% of Chronic Urticaria is MADE WORSE BY
ASA/NSAID use
Evaluating chronic urticaria
Encourage pt to take picture to show you
Often, no external cause can be identified
If physical trigger suspected, a challenge test with the trigger may be performed
IgE mediated food allergy more common with
Acute urticaria
Average duration of Chronic Urticaria
2-5 years,
but can extend beyond this
What can someone with Chronic Urticaria try
Avoid tight triggers
Stop Ibuprofen or other NSAID use
Start 1st gen Antihistamine i.e. Hydroxyzine
Reassurance for chronic urticaria
About 1/2 patients undergo remission within 1 year
1st line tx for Acute and Chronic Hives
Oral H1 Anthistamine
What types of ppl may require Renal dosing when taking H1 Antihistamines
Children
Elderly
Pts w Kidney or Live impairment
CAUTION in using H1 Antihistamines in
Glaucoma
Prostatic hyperplasia
Respiratory dz
1st Gen Antihistamine
Diphenhydramine
Hydroxyzine
Chlorpheniramine
2nd Gen Antihistamine
Cetirizine
Loratadine
Fexofenadine
Refer to derm if Hives have 1 of the following:
- last more than 48 hrs
- painful and burning
- systemic sx
- no response to Antihis
- leave pigment change upon resolution
Tx for Anaphylaxis
Epi
IVF
Oxygen
Adult dosage for Epi treating Anaphylaxis
0.3-0.5 mL in 1:1000 epi dilution IM
repeat every 10-20 min as necessary
Child <30 kg dosage for Epi treating Anaphylaxis
0.01 mL/kG
Most common cause of urticaria in kids is
Viral illness
“itchy red rash” waxing and waning, involving her face
mother has hx of Asthma and Allergic Rhinitis
sounds like ATOPIC DERMATITIS (eczema) case
Chronic, pruritic, inflammatory skin disease
Atopic Dermatitis
one of the most commin skin disorders in developed countries
Onset of Atopic Derm
usually b/w 3-6 mo
90% diagnosed by age 5
How often does Atopic Derm persist into adulthood?
30%
“The itch that rashes” bc Atopic Derm is itchy and then pts scratch it which makes it
WORSE
Distribution of Atopic Derm
Symmetric
Lesions are red and scaly
May display vesiculation, oozing, and crusting
More chronic lesions can even become lichenified
Lichenification
epidermal thickening with accentuated skin lines from chronic irritation
Atopic Derm for INFANTS and TODDLERS affects what body parts
Scalp
forehead
cheeks
Extensor surfaces
(back of arms, back of legs)
Atopic Derm for Older children affects what body parts
FLEXORAL areas
neck, elbows, knees, wrists, ankles
Eczema is a nonspecific term encompassing
Itchy
Erythema
Scale
Atopic Dermatitis is a more specific type of
Eczematous dermatitis
Factors thought to contribute to Atopic Dermatitis
Genetic pre-D
Skin barrier dysfx
Immune dysregulation
Environment
Best tx for a child’s face with Atopic Dermatitis
Hydrocortisone 2.5% ointment
Super high potency steroid
Clobetasol
like a CLUB, super STRONG
High potency steroid
Fluocinonide
Medium potency steroid
Triamcinolone
Low potency steroid
Desonide
Hydrocortisone
Bathing rec for someone with Atopic Derm
Apply moisterizer after bathing
Limit use of soap/cleanser
Dilute bleach baths
Refer pt with Atopic Derm to Dermatology when
Recurrent skin infection
Extensive/severe dz
Sx poorly controlled w topical therapy
Systemic therapy for Atopic Derm
Light therapy w NbUVB Immunosupp meds: -Cyclosporine -Mycophenolate mofetil -MTX -Azathioprine
Biologic drug for Atopic Derm
Dupilumab
monoclonal antibody directed against IL-4 and IL-3
If low dose steroid is not working to control flare
Increase dose, then taper off once sx are controlled
How is food related to AD
Food allergy is a known trigger in 20-30% of pts w Mod-Sev AD
Atopic march
Atopic derm –> Rhinitis –> Asthma
Explaining Atopic Derm boy’s foot
Lichenified red plaques with overlying scale, fissuring, hemorrhagic and brown crust
What do you need to consider in pts that have Weepy flares of AD?
i.e. when Pustules, Erosions, or Crusting are present- yellow, brown, hemorrhagic
Skin Bacterial Culture
bc secondary infection from Staph or Group A Strep is common
Way to describe the boy
s face that had white spots
Poorly defined HYPOPIGMENTED patches w fine scale on the face
Pityriasis Alba may present as
Poorly defined hypopigmented patches w fine scale on the face
What is Pityriasis Alba?
Mild, often no sx, form of Atopic Derm of the face
Poorly marginated, hypopigmented, slightly scaly patches on the CHEEKS
Pityriasis Alba
Who is Pityriasis Alba usually found in?
Young children w darker skin
often in spring or summer when the unaffected skin tans, becomes more noticeable
Tx for Pityriasis Alba
Moisterizer BID
Sun protection
If no improvement of Pityriasis Alba after moisterizing and sun protection, consider
- Low strength topical steroid
- Topical calcineurin inhibitor
Long term tx for AD vs Acute care
Emollients and gentle care
Acute flare: topical steroids
