Irritant Contact Dermatitis

Question 1

Fiberglass dermatitis

Answer 1

Injury via skin penetration → pruritus/tinging → pink papules
■ Rx: talcum powder

Question 2

Alkalis

Answer 2

■ Strong alkalis are corrosive: dissolve keratin and penetrate deeply → worse rxns than acids
■ Ca/Na/K hydroxides; ammonia; lye
■ Soap, detergent, bleaches, and depilatories
■ Treatment: apply weak acid (vinegar or lemon juice)

Question 3

Acids

Answer 3

■ Powerful acids are corrosive and weaker ones are
astringent (a compound that shrinks or constricts
tissues)

■ Sulfuric acid
○ Causes severe burns, produces brownish staining
○ Brass and iron workers, battery makers, jewelers, weapon of vitriol attacks (“acid throwers”)

■ Nitric acid
○ Distinctive burns with yellow discoloration
○ Explosives, fertilizer

■ Hydrofluoric acid
○ Penetrates very deeply due to low dissociation rate
→ severe damage to bones, nerves; exquisitely painful; symptoms may be delayed for up to 24 hrs
○ Used for dissolving/etching glass in semiconductor industry
○ Rx: neutralize w/ calcium gluconate gel, seek emergency care

■ Hydrochloric acid
○ Superficial burn → produces blisters

■ Oxalic acid
○ Paresthesia of fingertips; cyanosis; gangrene

■ Phenol
○ Used in cosmetic peels
○ Produces white eschar and temporary anesthesia; systemic absorption → glomerulonephritis and arrhythmias
○ Neutralized by 65% ethyl or isopropyl alcohol

Question 4

Urticaceae family (nettle)

Answer 4

Urtica dioica

• Sharp hairs on plants contain toxins (histamine, serotonin, and acetylcholine) → rapid edema, pruritus, and burning

Question 5

Opuntia spp. (prickly pear)

Answer 5

Causes glochid dermatitis: mechanical ICD as a result of larger spines or smaller glochids (collections of short barbed hairs) that cause penetrating injuries → inoculation of C. tetani, S. aureus, S. shenckii, and atypical mycobacteria

 Remove larger pieces w/ tweezers; use glue and
gauze for smaller pieces

Question 6

Bromelin

Answer 6

Ananas cosmosus (pineapple)

Question 7

Calcium oxalate

Answer 7

Family Amaryllidacea/Lilaceae

• Daffodil (Narcissus spp.), hyacinth, and tulip
  bulbs
• Most common cause of ICD in florists, “daffodil itch”

Family Araceae

• Dumb cane (Dieffenbachia; house plant)
• Ananas comosus aka Pineapple (also contains bromelin)

Question 8

Phorbol Esters

Answer 8

Family Euphorbiacea

• Croton plant, spurges, poinsetta
• Diterpines (latex)
• May cause temporary blindness

Question 9

Protoanemonin/rarunculin

Answer 9

• Buttercups, marigolds
• Classic linear vesicles like phytophotodermatitis, but no hyperpigmentation after