Chapter 6 Contact Dermatitis Flashcards
What is irritant dermatitis? Allergic contact derm?
- Inflam rxn in skin resulting from exposure to substance that causes eruption in most people who come in contact with it
- Acquired sensitivity to various substances that produce inflam rxn only in those persons who have been previously sensitized
T/F atopic patients are predisposed to irritant hand dermatitis
True
T/F acids penetrate and destroy deeply because they dissolve keratin
False - alkalis
Acid that produces burns that are less deep and more liable to form blisters
Hydrochloric
Acid that produces brownish charring of skin beneath which is an ulceration that heals slowly
Sulfuric
- handled by brass and iron workers, also with copper and bronze
Acid that is a powerful oxidizing substance that causes deep burns, stains yellow
Nitric acid
Acid used widely in rust remover, semiconductor industry, germicides, dyes, plastics and glass etching
Strongest inorganic acid capable of dissolving glass
Hydrofluoric acid
- hypocal hypomag hyperkal dysrhythmias
- neutralized with hexafluorine solution -> 10% Ca gluc or mag oxide
Acid that may produce paresthesia of fingertips with cyanosis and gangrene, yellow discoloration of nails
Oxalic
- neutralize with limewater or milk of magnesia
Acud used in manufacture of pigments
Titanium hydrochloride
Acid that is protoplasmic poison that produces white eschar
Phenol / carbolic acid
- neutralize with 65% ethyl or isopropyl alcohol
- large amount -> GN, arrhythmia
Acid in electroplating and dye production, extensive tissue necrosis and renal damage
Chromic
- excision to fascia rapidly, HD to remove within 24h
What is irritant dermatitis? Allergic contact derm?
- Inflam rxn in skin resulting from exposure to substance that causes eruption in most people who come in contact with it
- Acquired sensitivity to various substances that produce inflam rxn only in those persons who have been previously sensitized
T/F atopic patients are predisposed to irritant hand dermatitis
True
T/F acids penetrate and destroy deeply because they dissolve keratin
False - alkalis
Acid that produces burns that are less deep and more liable to form blisters
Hydrochloric
Acid that produces brownish charring of skin beneath which is an ulceration that heals slowly
Sulfuric
- handled by brass and iron workers, also with copper and bronze
Acid that is a powerful oxidizing substance that causes deep burns, stains yellow
Nitric acid
Acid used widely in rust remover, semiconductor industry, germicides, dyes, plastics and glass etching
Strongest inorganic acid capable of dissolving glass
Hydrofluoric acid
- hypocal hypomag hyperkal dysrhythmias
- neutralized with hexafluorine solution -> 10% Ca gluc or mag oxide
Acid that may produce paresthesia of fingertips with cyanosis and gangrene, yellow discoloration of nails
Oxalic
- neutralize with limewater or milk of magnesia
Acud used in manufacture of pigments
Titanium hydrochloride
Acid that is protoplasmic poison that produces white eschar
Phenol / carbolic acid
- neutralize with 65% ethyl or isopropyl alcohol
- large amount -> GN, arrhythmia
Acid in electroplating and dye production, extensive tissue necrosis and renal damage
Chromic
- excision to fascia rapidly, HD to remove within 24h
Tx of airbag dermatitis
Topical steroids
Debridement and grafting for full thickness burns
Applied on flexural areas to prevent fiberglass dermatitis
Talcum powder
May completely relieve burning of capsaicin irritation
Acetic acid / white vinegar
Antacids
Skin lesion of chloracne, histology, treatment
Small straw colored follicular plugs and papules, on malar crescent, retroauricular earlobes neck shoulders scrotum
Loss of sebaceous glands, formation of cystic structures
Isotretinoin
Symptoms of crude petroleum dermatitis
Generalized itching folliculitis or acneiform eruptions
Insoluble neat cutting oils dermatitis result to
Follicular acneiform eruption on hands forearm face thigh back of neck
Soluble oils and synthetic fluids in metalworking -> dermatitis result to
Eczematous dermatitis on dorsal hand and forearm
May occur from exposure to mineral oils and low grade petroleum from creosote asphalt other tar
Melanoderma
Follicular keratosis and pigmentation resulting from crude petroleum tar oils and paraffin
Acne corne
Chlorinated hydrocarbon solvent and degreasing agent when inhaled may produce exfoliative erythroderma, mucous membrane erosions, eosinophilia, hepatitis
Trichloroethylene
Most common relevant allergens in childhood
Nickel cobalt fragrance
What is babboon syndrome or SDRIFE
Deep red violet eruption on buttocks genital inner thighs and axillae
T/F contact urticaria to a substance may concomitantly have a type IV delayed sensitization and eczema from same allergen
True
Body part used for patch test
Upper back
Patch removed after 48h or sooner, sites evaluated at day 4/5 or even up to 7 days
Erythematous papules and vesicles with edema
Why is the oral mucosa more resistant to irritants?
Keratin layer more readily combines with haptens to form allergens
How to do provocative use test
Material rubbed to skin of inner aspect of forearm several times a day for 5 days
How to do photopatch test
Patch applied for 48h, exposed to 5-15J/m2 of UVA, read after 48h
Toxicodendron dermatitis includes dermatitis from what plant family
Anacardiaceae
Symptoms of toxicodendron derm
Pruritus followed by inflammation vesicles bullae, linearity of lesion
Tx of severe extensive plant derm
40-60mg prednisone OD tapered in 3wks
Allergenic substance in poison ivy abd vesicant oil
Uroshiol
Cardol
Houseplant frquently causing contact derm
Money plant or philodendron crystallinum
Most common flower causing allergic contact derm in florists
Peruvian lily
- tulip fingers
Acid causing sensitization by lichens
D-usnic acid
2 antigens of pollens in ragweed
Protein - respiratory symptoms of asthma, hay fever
Oil soluble - contact dermatitis
Chief sensitizer derived from plants found in oleoresin fractions
Essential oils
Most common cause of clothing dermatitis
Fabric finishers
Dyes
Rubber additives
Diagnostic point in shoe dermatitis
Normal skin between toes
- most frequently caused by rubber accelerators mercaptobenzothiazole, carbamates, tetramethylthiuram disulfide
Metal dermatitis most frequently caused by
Nickel and chromates
Most common causes of allergic derm in rubber manufacturing
Accelerators - disulfiram, thiuram
Antioxidant - propyl-p-phenylenediamine
Components of epoxy resins
Resin 90% of allergic rxn
Hardener 10%
Leading cause of cosmetic dermatitis
Fragrance followed by preservatives then p-phenylenediamine in hair dye
Primary irritants in hair bleach
Peroxide
Persulfate
Ammonia
Allergen of acid perm
Glyceryl monothioglycolate - persists for at least 3mos in hair
Substance in chemical depilatories causing irritant dermatitis
Calcium thioglycolate, sulfides, sulfhydrates
Frequent cause of eyelid and neck derm in nail lacquers
Tosylamide/formaldehyde resin
Most common sunscreen allergen
Oxybenzone
Allergy to PABA may cause dermatitis from cross rxns to
Thiazide Sulfonylureas Azo dyes P-aminosalicylic acid Benzocaine PPDA
Drug transdermal patch with highest rate of allergic rxn
Clonidine
Drugs that may cause anamnestic/recalled eruption or systemic contact derm
Antihistamines
Sulfonamides
Penicillin
topical anesthetic that is the Most common sensitizer
Benzocaine
T/F white petrolatum is as effective in wound healing as antibiotic ointment in clean surgical procedures
True
What are the occupations with the highest incidence of occupational skin disease?
Agriculture Forestry Fishing Manufacturing Healthcare
T/F nonimmunologic is the most common contact urticaria
True
How to do open patch test
Substance applied to 1 cm sq area on forearm and observed for 20-30min for erythema wheal and flare
Secretion of T cells in the dermis in acute gen exanthematous pustulosis (AGEP)
IL-8 neutrophil attacking chemokine
Secretion of T Cells in drug rash with eosinophilia and systemic symptoms
IL-5
Eotaxin
Recruiting eosinophils
Type of rxn when T cells stimulate IFN-y production and Th1 response (contact derm)
Can be bullous but without extensive epidermal necrosis
Type of rxn when T cells activated to function in a Th2 manner, stimulate eosinophil
Morbilliform and urticarial
Type of rxn when T cells activate CD8+ T cells, secrete perforin/granzyme B and Fas ligand, result in keratinocyte apoptosis (CD8 cells attack all MHC class I cells hence more severe rxn)
Bullous rxn
Type of rxn in T cells through cytokine production recruit neutrophils
Pustular exanthem
AGEP
T cells reduced in severe bullous drug eruptions such as TEN
CD4/CD25/Foxp3 regulatory T cells or Tregs
Drugs most commonly causing morbilliform/maculopapular rxn
TMP-SMX
Penicillins
Characteristics of DIHS And DRESS
Rash developing >3wks after starting drug
Lasting symptoms >2wks after discontinuation
Fever >38deg
Multiorgan development
Eosinophilia >1500
Lymphocytosis, atypical lymphocytosis, lymphadenopathy
Frequent activation of HHV6 HHV7 EBV CMV
Most common anticonvulsant causing DRESS
Carbamazepine
T/F allopurinol hypersensitivity syndrome typically occurs in preexisting liver failure
False - renal
Most common mucosal surfaces eroded in SJS
Oral mucosa
Conjunctiva
Percentage of skin lesion in SJS and TEN
SJS/TEN overlap >10% skin surface
TEN >30%
Internal involvement in SJS/TEN
Eosinophilia
Hepatitis
Worsening renal function
What is SCORTEN for SJS/TEN
Predict mortality (age malignancy tachycardia renal failure hyperglycemia low bicarbonate)
1 pt for each
3.2% mortality for 0-1pt
90% for 5/more
Respiratory excluded
Mechanism of keratinocyte death in SJS/TEN
Cytotoxic T cells, NK cells produve granulysin, perforin, granzyme B
Binding of soluble Fas ligand to Fas (death receptor / CD95)
Most promising drug to treat SJS/TEN
Cyclosporine
Survivors of SJS/TEN average time for epidermal regrowth,
Most common complication / sequelae
3 weeks
Ocular scarring and vision loss
Drugs associated with radiation induced EM
Phenytoin
Amifostine
Phenobarbital
Levetiracetam
HIV patients increases risk for development of ADR at what Th cell count
25-200
Nevirapine hypersensitivity syndrome presents with
Fever hepatitis rash
First 6wks treatment
FDR/E most commonly occurs where
Oral and genital mucosa
- with refractory period
Skin lesion of FDE
Red patch evolving to iris/target lesion similar to EM and may eventually blister and erode
Histology of FDE
Interface dermatitis with subepidermal vesicle formation
Necrosis of keratinocytes
Superficial and deep infiltrates of neut eo and mononuclear cells
Pathognomonic skin layer changes in FDE
Normal stratum corneum and chronic dermal changes
When and how to do oral provocation test in FDE
2wks from last eruption
Initial challenge 10% of standard dose AND do not challenge if with Widespread SJS/TEN
Most common cause of AGEP
Drugs 90%
Most common systemic involvement in AGEP
Respiratory
Most common drug induced pseudolymphoma
Cutaneous T cell lymphoma
Anticonvulsant sulfa drugs dapsone antidepressants vaccination herbals
Drugs Most common cause of non immunologic urticarial lesions
Aspirin
NSAIDs
(Alter PG metabolism enhancing degranulation of mast cells)
Immunologic urticaria most often associated with
Penicillin
Related beta lactam
T/F Second gen cephalosporins less likely to induce rxn in penicillin allergic pt than first or third
False - third
Angioedema is a known complication of which drugs
ACEI and ARBs
ACEI - block kininase II increase kinin
Most medication related photosensitivity triggered by what UV range
UVA
- absorption spectra of most drugs and short range 315-430
- penetrates into dermis where drug is present
- NSAID TMPSMX thiazides sulfonylureas quinine quinidine phenothiazine tetracycline
Drug most frequently causing pseudoporphyria
Naproxen
Patient features predisposed to anticoagulant induced skin necrosis
Obese postmenopausal
- 3-5d after therapy, red painful plaques then petechiae then bulla then necrosis
- histo: non inflam thrombosis with fibrin in subcutaneous and dermal vessels
- tx: stop warfarin, give vit K, LMWH, giving purified protein C rapidly reverses
IV drugs related to injection site rxn
Chemo
Calcium salts
Radiocontrast
Nafcillin
Syndromes in IM injection site rxn
Embolis cutis medicamentosa
Livedoid dermatitis
Nicolau syndromes- periarterial injection leading to arterial thrombosis
Minocycline induced pigmentation with 2 types - describe
Type I blue black discoloration in areas of prior inflammation often acne or surgical scar
Type II similar but on anterior shin
Type III gen muddy brown hyperpigmentation accentuated in sun exposed areas
Histo: pigment granules within macrophages in dermis and at times fat resembling tattoo
Stain for both iron and melanin
Presentation of amiodarone induced hyperpigmentation
Slate gray in areas of photosensitivity
After 3-6mos
Drug inducing hyperpigmentation in Hansens disease
Clofazimine
Pink then reddish blue or brown in Hansens lesions
Drug induced lipofuscinosis
Most common heavy metal induced pigmentation
Silver
Local and systemic argyria
- binding to sulfur or selenium, activates tyrosinase increase pigmentation
Drug that can induce true leukocytoclastic vasculitis
Propylthiouracil
Skin gland that is a unique target for adverse rxn to antineoplastic agents
Eccrine gland
Tx of chemo induced acral erythema
Cold compress
Elevation
Cooling hands
Modification of dose schedule
Tx of hand foot skin rxn in multikinase inhibitors
Topical tazarotene, 40% urea, Heparin ointment fluorouracil cream
Component of mushroom causing toxicodermia or shiitake flagellate dermatitis
Lentinan
Chemo drug causing gen or localized dyspigmentation, inability to tan, ‘photosensitivity’
Imatinib
- proposed mechanism inhibition of stem cell factor
*sunitinib causing depigmentation of hair after 5-6wks of treatment
Chemo drug causing exudative hyponychial dermatitis
Docetaxel
Primary lesion in side effect of EGFRI
Follicle papule or pustule with few or no comedones
Tx: topical metronidazole, clindamycin, hydrocortisone, pimecrolimus, tretinoin
Cutaneous side effect of Imatinib, sunitinib Dasatinib Bevacizumab Sorafenib
Facial edema with periocular predilection
Lobular panniculitis
Bleeding, wound healing complications, ulceration of striae distensae
Keratoacanthomas or SCC, eruptive melanocytic lesions
Exacerbation of leukocytoclastic vasculitis associated with what drugs
Exacerbation of psoriasis associated with
G-CSF and GM-CSF
IFN-alpha, IFN-y, G-CSF
Skin Presentation of injection site rxn fron TNFi
Erythematous mildly swollen plaques 1-2d after injection
Paradoxic appearance of psoriasis or psoriasiform dermatitis occurs more commonly in which TNFi
Infliximab
Etanercept
Adalimumab
Mechanism: overactivity of Th1 cells or inc IFN-alpha production by skin-resident plasmacytoid dendritic cells
Tx: topical corticosteroids, UV photoThx, topival vit D analogs, methotrexate, acitretin, cyclosporine
Pathognomonic characteristic of acrodynia or mercury poisoning
Painful swelling of hands and feet sometimes associated with itching
- diffuse symmetric erythematous morbilliform eruption in flexors and proximal extremities within a few days of exposure
Tx: succimer, seafood free diet
Drugs causing drug induced lupus
Hydralazine Isoniazid Penecillamine Procainamide PTU Quinidine Captopril Minocycline Carbamazepine Sulfasalazine Statins
Drugs most commonly causing subacute cutaneous lupus
HCT
Diltiazem and other ccb
Terbinafine
Linear IgA bullous dermatosis especially associated with which drug
Vancomycin
Tx: stop drug, dapsone 100-200mg OD
Explanation for LT receptor antagonist associated churh strauss syndrome
Unopposed LT B4 activity - chemoattractant for eo and neutro
Skin changes most frequently seen after corticosteroid use
Atrophy Striae Telangectasia Skin fragility Purpura
- steroid should be substituted by pimecrolimus or tacrolimus
T/F atopic children with >50% BSA involvement have short stature
True
