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Summer Fun with Plants, Bugs and Other Pests

Stephen E Helms, MD Professor, Department of DermatologyUniversity of Mississippi Medical Center

Diagnostic and Treatment Pearls for Primary Care

August 10, 2019

Disclosures

I do not have any relationships with industry relevant to this discussion

I May Mention Brand and/or Company Names

DERMATOLOGIC REACTIONS DUE TO PLANTS

UrticariaImmunologicToxin mediated (Non-immunologic)

Irritant dermatitisMechanicalChemical

Allergic contact dermatitisPhototoxic dermatitis

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Immunologic ---- Contact Urticaria Comes about as a result of frequent contact with fruit and vegetables,

atopy may contribute

May present as urticaria, pruritus, burning. Can evolve into allergic contact dermatitis with repeated exposure to plant proteins

What is the most common plant of systemic contact urticaria?Celery (Apium graveolens)

Other plants that can be offendersCarrot, Cucumber, Tomato, Garlic, Lemon, Onion

Toxin-Mediated (Non-Immunologic) Urticaria What is the most common cause?Stinging nettles, Urtica dioicaDue to substances contained in their trichrome (hair)Sensitization not required Histamine, Serotonin, Acetylcholine

More common than immunologic urticaria Anyone can be affected May show urticaria clinically OR only a stinging sensation with no

rash

Stinging Nettle, Urtica dioicaFlowering plant Magnification of trichromes

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Typical urticarial reaction to stinging nettle:

Irritant Contact Dermatitis from Plants 1) MechanicalFrequently caused by certain Cactus plants or their fruitsDamage is caused by large spines or small thorns and fish-hook-

shaped spines (glochids)

2) ChemicalCapsaicin -- cooks of Korean/ Chinese food – Erythema and dysesthesia – wash with soap and water

followed by oil to remove fat-soluble capsaicinCalcium oxalate ---Common irritant in daffodils that cause

irritant dermatitis -- “daffodil itch” Bromelin (stem>fruit) ----Pineapple dermatitis Ca Oxalate-induced microabrasions aggravate the situation

Irritant Contact Dermatitis

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“Allergic to Flags for Invisible Fence”What else?

Should we patch test to the flags?

Phytophotodermatitis

• A cutaneous phototoxic inflammatory eruption resulting from contact with light-sensitizing botanical substances (usually furocoumarins which are psoralen isomers) and long-wave ultraviolet A (UV-A, 320-380 nm) radiation.

• Non-immunologic (Again, no prior allergic sensitization required)

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Postinflammatory hyperpigmentation may last weeks to months

• Phytophotodermatitis typically manifests as a burning erythema that may subsequently blister.

Berloque dermatitis from limes

Phytophotodermatitis, causative agentsApiaceae Family (celery, wild parsnip, parsley, hogweed wild carrot)

Rutaceae Family ( lime, lemon )

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J Community Hosp Intern Med Perspect. 2014 Harkinson A, Lloyd B, Alweis R

Acute Facial Contact DermatitisPhotocontact Dermatitis

Photo Contact Dermatitis• Fragrances

– Musk ambrette

– Oil of Bergamot– Sandalwood Oil

• Plants– Lemon, Lime, Celery, Fennel, Parsley, Parsnips

• Sunscreens– Benzophenones (Oxybenzone most frequent cause)

– Avobenzone(Parsol1789,Butylmethoxydibenzoylmethane)

– Cinnamates

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Benzophenones—Contact allergen of the year 2014---to raise awareness of both allergy and photoallergy to these ubiquitous agents

• Initially-- preservatives in industrial products such as paints, varnishes, and plastics to extend shelf life and reduce photodegradation

• 1950s-- introduced into sunscreens• chemical ultraviolet light absorbers• primarily absorb light in the UV-B range (290-320 nm)• benzophenone-3 (Oxybenzone) and benzophenone-4 (Sulisobenzone)

also absorb UV-A II light (321-340 nm)Ashley R. Heurung, BS, Srihari I. Raju, MD, and Erin M. Warshaw, MD, MSDERMATITIS, Vol 25 No 1 January/February, 2014

Other Sunscreens

• Avobenzone NOT a Benzophenone (Parsol 1789)

• Photosensitizer in lip balms• Octocrylene a UVL filter in cinnimate family used as

a stabilizer for Avobenzone may actually cross react with Benzophenone 3 (Oxybenzone)

Allergic Contact Dermatitis

• What are the two most common etiologies of ACD?NickelPoison Ivy

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Allergic Contact Dermatitis (ACD) from Plants

Two main plant families: Anacardiaceae and Asteraceae, --- also Alliums (onion and garlic family) and Liliaceae (Lilies)

1. Anacardiaceae The proper name for poison ivy?

Toxicodendron radicans (Eastern) (rydbergii –shrub, Western)What is the mediator of the ACD?

Urushiol *Poison Ivy cross reacts with: Mango, Cashew, Brazilian Pepper tree, Japanese Lacquer tree…

• Toxicodendron dermatitis affects up to 10 to 50 million Americans per year.

• Approximately 50% to 75% of the US adult population is clinically sensitive to poison ivy, oak, and sumac.

• It affects all ethnicities, skin types, and ages, and most geographical regions in the United States are at risk.

• Toxicodendron dermatitis is a major contributor to the 9 million office visits and 1.6 million hospital outpatient visits for contact dermatitis in the United States annually

Poison ivy, poison oak, and poison sumac --Anacardiaceae family of plants --genus Toxicodendron.

• “Ivy” 3 leaves– Toxicodendron rydbergii, a nonclimbing, dwarf shrub in northern and

western US– Toxicodendron radicans, a climbing vine in eastern US

• “Oak” 3 to 5 leaves– Toxicodendron toxicarium and Toxicodendron diversilobum.

• “Sumac” 7 to 13 smooth-edged leaves – Toxicodendron vernix -- small shrub grows in moist, swampy areas.

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Allergic Contact Dermatitis Due to Plants - Toxicodendron

Poison Ivy and Oak

Poison ivy –color change

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PLANT DERMATITIS

Plant Dermatitis

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Is a Poison Plant Rash Contagious?Not true, but: You can “spread the rash” only if you have urushiol on your hands, arms, etc. or clothing. It can take longer for the rash to appear on certain areas of the body.

Appearance that the rash has spread from one part of the body to another.

Re-exposure to the urushiol by touching gardening tools, gloves, shoes, sports equipment, etc. Scratching or touching the rash and fluid from blisters will not cause the rash to spread because urushiol is not present in the blister fluid.

What to do if exposed?

• Remove your clothes.• Wash all exposed areas. Use soap and water if possible. In

the woods, the water of a running stream can be an effective cleanser.

• Wash clothing and all gardening tools, camping gear, sports equipment, and other objects that came into contact with the plants.

• Bathe pets exposed to the plants.

Allergic Contact Dermatitis (ACD) from Plants

2. Asteraceae(pollens like ragweed)Formerly CompositaeMajor allergen is sesquiterpene lactonesMost common plant within the family

to cause?Chrysanthemums

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Other Plant Families that can cause allergic contact dermatitis

3.Alliaceae family In this family, garlic is major cause of what?

Finger tip dermatitisUsually on non-dominant hand Don’t do patch test to whole garlic, main allergen is Diallyl disulfide Common disposable gloves do no protect sensitized people, silver laminate gloves

may provide partial protection.

4. Alstromeriaceae familyTulips, Peruvian Lily (Alstromeria)Tulip dermatitis

Caused by which plant protein?Tuliposidase A (tulipalin A), and to a lesser extent tuliposidase B

“Tulip fingers” Usually seen in florist and plant handlers **Tuliposide A tends to cause hyperkeratotic or lichenified plaque in area of contact, usually

finger

Alstromeria,“Peruvian

Lily”

Allergic Contact Dermatitis due to Alsteromeria in a florist

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What is this plant?

Cannabinoids in DermatologyMounessa J, Siegel J, et al

J Am Acad Dermatol 2017;77:188-90.

• CB1: cannabinoid 1• CB2: cannabinoid 2

• PEA: palmitoylethanolamide• THC: tetrahydrocannabinol

• Anti-itch effect• Inhibit Keratinocyte proliferation

• Anti-inflammatory effect• Anti-tumor effect

Allergic Contact Dermatitis from a new botanical source, topical cannabinoids, AKA CBD Oil Adler BL, DeLeo VA, Allergenic ingredients in commercial topical cannabinoidpreparations, Journal of the American Academy of Dermatology (Online March 15, 2019)

• Topical cannabinoids are available in a variety of vehicles with creams and lotions greatly outnumbering ointments; only 16% of products were free of NACDG allergens

• 31% of products had 1-2 allergens, and 56% had 3 or more • Tocopherol and fragrance were common, but topical cannabinoids also

often contained botanical allergens, notably peppermint and lavender in about one-third of products..

• Cannabis itself has been reported to cause immunologic contact urticaria and airborne allergic contact dermatitis

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Botanical ingredients found in greater than 10% of topical cannabinoids.

Ingredient Frequency (N [%])

Ingredient Frequency (N [%])

Ingredient Frequency (N [%])

Coconut 52 (51)Peppermint/menthol * 37 (36)Lavender * 33 (32)Beeswax 30 (29)Shea 27 (26)Sunflower 25 (24)Aloe vera * 23 (22)Arnica * 18 (18)Eucalyptus * 17 (17)Rosemary * 17 (17)

Ginger * 15 (15)Almond 14 (14)Arnica * 18 (18)Eucalyptus * 17 (17)Rosemary * 17 (17)Ginger * 15 (15)Almond 14 (14)Jojoba 14 (14)Tea tree * 14 (14)Avocado 13 (13)

Chamomile * 13 (13)Marigold * 11 (11)Cocoa 11 (11)Orange * 11 (11)Argan 10 (10)Frankincense * 10 (10)Grapefruit * 10 (10)Tamanu 10 (10)

What is this rash and what causes it?

Cutaneous larva migrans (also known as creeping eruption)

Hookworm that do not use humans as a definitive host but are intestinal parasites of dogs and cats.

Ancylostoma braziliense and A.caninum caninum.

Generally treated now with Ivermectin.

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Hookworm life cycle

What are the clinical features of papular urticaria?• Papular urticaria presents with very itchy clusters of red bumps.• Most often they arise on legs and other uncovered areas such as

forearms and face.• Sometimes papules are scattered in small groups all over the body.• Can range from 0.2–2 cm in diameter.• May see a central punctum.• May present as crops of fluid-filled blisters.• Scratching papular urticaria causes the spots to become eroded,

maybe infected and crusted.

What might this be?

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Insect bites-- central puncta

Linear

bites

Vescicular insect bites

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Insect bites Impetiginized

Mosquito species responsible for:

Malaria Dengue Fever West Nile Virus Zika Chikungunya Yellow Fever

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Insect bites - treatmentA. Prevention best treatment

1. Insect repellents/Insecticides 2. Barriers – stay indoors, clothing, netting, etc3. Minimize “standing water”

B. Prevent infection1. Antihistamine2. Topical corticosteroid3. Systemic corticosteroid

Repellent vs. Insecticide

• Insect repellent: chemical or organic agent that makes the atmosphere within 4 cm of skin so noxious as to discourage contact and biting

• Insecticide: a chemical or organic agent that kills insects, typically with a neurotoxin

• Some repellents are also insecticides (e.g., permethrin and synthetic pyrethroids)

• FDA approves insect repellents• EPA approves insecticides

• Many insecticides are approved for outdoor use only• Pyrethroids are the only insecticides approved for indoor use

Thanks to Julian Trevino, MD Chair Division of DermatologyWright State University College of Medicine

Insect Bites and their Prevention (the things we have no control over)

Mosquitoes attracted by:MoistureWarmthCO 2

OdorEstrogen

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Insect Bites – Prevention – things we can do and should know about Repellents

• Applied to skin or clothing• Produce a vapor layer that has an offensive smell

or taste to insects• Repellent barrier extends only 4 cm from the

skin when freshly applied• Sweating, washing, warm temperatures, and

high winds decrease duration of effectiveness

NOTE: The following types of products are NOT effective repellents:

• Wristbands soaked in chemical repellents• Garlic or vitamin B1 taken by mouth• Ultrasonic devices that give off sound waves designed to

keep insects away• Bird or bat houses• Backyard bug zappers (Insects may actually be attracted

to your yard).

Active Ingredient OptionsActiveIngredient

Type EPARegistered?

Duration

DEET Chemical Yes 8-10+ hours

Picaridin Chemical Yes Up to 8 hours

Oil of lemoneucalyptus

Synthesizedplant oil

Yes Up to 6 hours

IR3535Synthesizedplant oil

Yes 4-8 hours

Plant oils (soybean,lemongrass, cedar,citronella, etc.)

Nonsynthesizedplant oil

NoEstimated 30 min.to 2 hours

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DEET Was N,N-diethyl-M-toluamide (Developed by the U.S. Army in 1946, commercially available in 1956)Now N,N-diethyl-3-methylbenzamide

• “Best” >60yrs compared to 10,000’s of compounds, effectiveness maximizes at 50% concentration

• 200 million people use each year, safe in pregnancy (2-3rd trimester) and children over 2 years of age (up to 33% concentration)

• Broad spectrum– mosquitoes, biting fleas, gnats, chiggers, ticks, and others

• Safe—cotton, wool, nylon• But

– May damage—spandex, rayon, acetate, and pigmented leather– May dissolve plastic and vinyl Eyeglasses Vinyl car seats Nail polish

Insect Repellents DEET

OFF! Deep Woods (SC Johnson) 23%Sawyer Controlled Release (Sawyer) 20%OFF! Skintastic (SC Johnson) 6.65%OFF! Skintastic for Kids (SC Johnson) 4.75%

Effective for 300 → 88 minutes of protection

Fradin MS, Day JF N Engl J Med July 2002

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From the American Academy of Pediatrics:• DEET is a chemical used in insect repellents. The amount of DEET in

insect repellents varies from product to product, so it’s important to read the label of any product you use. The amount of DEET may range from less than 10% to more than 90%. DEET greater than 50% doesn’t offer any additional protection.

• Studies show that products with higher amounts of DEET protect people longer. For example, products with amounts around 10% may repel pests for about 2 hours, while products with amounts of about 24% last an average of 5 hours.

• The AAP recommends that repellents should contain no more than 33% DEET when used on children. Insect repellents also are not recommended for children younger th an 2 months.

Picaridin• Created by Bayer in the 1980s, picaridin (pronounced pih-CARE-a-den) is a

synthetic compound developed from a plant extract from the genus Piper, the same plant genus that produces table pepper. Picaridin has been available since 1998 in Europe and Australia—where it is the best-selling insect repellent—but was approved for sale in the United States only in 2005.

• Advantages over DEET:• Lack of chemical odor• No sticky/greasy feeling• Lack of damage to clothing or plastics

• No reported dermal, solid organ or reproductive toxicity

Picaridin (icaridin, continued•Effective against mosquitoes, ticks, biting flies, chiggers•No serious adverse events reported •Available as 7% solution; 15% aerosol spray, effective for approx. 2 hours. •20% concentration up to 8+ hours!•Not recommended in children < 2 years of age

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IR 3535 (Ethyl butylacetylaminopropionate)

• Colorless and almost odorless oil and is intended to be applied to the skin of humans and animals.

• Broad efficacy against various insects -- mosquitoes, ticks, lice, and other bugs.

• Safe for use on infants, pregnant and breastfeeding women. • Biodegradable and completely degraded in the environment within a

very short time

Insect Repellents Botanical (Effective)

•Oil of lemon eucalyptus- effective against mosquitoes, ticks, biting flies, gnats•Available as 10-40% pump; efficacy similar to lower concentration DEET (7-15%)•Not for use in children < 3 years old

Insect RepellentsBotanical (Not So Effective)

Citronella – poor stability and short duration, associated with eye irritation and allergic contact dermatitis.-effective against mosquitoes, not effective for fleas, ticks, biting midges-microencapsulation for use as a repellent in fabric

Catnip oil, methyl nonyl ketone have minimal effectiveness, not recommended

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Only Clothing-applied IR

• Permethrin– A pyrethin (chrysanthemum flower extract), should not be applied directly to the

skin, is only to be used to treat clothing, shoes, beds, nets, camping gear – re-apply after 5 washings

– Acts as both insecticide and repellent– Highly effective against ticks, mosquitoes and fleas equally, repels ticks more

effectively than DEET

52 y o physician “sore on leg 3 days”

Brown Recluse Spider

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(Loxoscelesreclusa)

• Sphingomyelinase D• Supportive Tx• Cold/Ice packs• Do NOT apply heat• No Antivenom• Dapsone (controversial)• Steroids ? • Antibiotics

Widow spiders◦ Latrodectus mactans is the most common black widow spider

– shiny and black with an hourglass marking on the abdomen.◦ Venom contains latrotoxins that act as neurotoxins to

depolarize neurons.

EnvenomationMildModerateSevere

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Black widow spider antivenom

Information managing bitesMedical Toxicologist ----Through regional US poison control center1-800-222-1222

• If moderate to severe symptoms not responsive to supportive care

• Merck national service center

• 1-800-672-6372