28 Practical October 2008 hese days, it is common knowledge that visiting tact with the . Extensive involvement of the hands the beach on a bright summer day without sun and mouth region is also common due to the eating and han- protection is harmful to your skin. But did you dling of the plants. The clinical manifestation of phytophoto- know that skin damage could also occur from can be confusing to healthcare provider and patient T using a laptop on your legs? Many people are not alike and can be mistaken for child abuse, atopic dermatitis, aware that exposures to common things found in our daily scalding cellulitis, or fungal infection. However, a thorough environment—such as sunlight, heat, insect bites, plants, and history that reveals past contact with one of the offending sand—can actually cause skin manifestations. So as the sum- plants and sunlight exposure often helps in clinching the diag- mer heat gives way to the sight of falling leaves and jack-o- nosis.3 lanterns, here are five different types of dermatologic condi- Preventing this condition involves avoidance of exposure tions that can result from common environmental exposures and use of protective clothing when outdoors. Treatment is pri- and may present in your practice. marily symptomatic, as the skin lesions tend to resolve sponta- neously over the following weeks and months.3 Analgesics, Condition: Phyt ophot oder m a titis antihistamines for itching, and wet compresses may be used to Sour ce: Sun e xp osur e alleviate pruritus that may be related to acute erythematous or Phytophotodermatitis occurs when the radiant energy of the bullous lesions. Additionally, blistered areas should be kept sun interacts with particular photosensitizing compounds clean to prevent any secondary infection of the skin. Early and found in a number of plants. These photosensitizing agents short use of a topical steroid (triamcinolone 0.1% cream twice include several isomers of psoralens, also known as furo- daily) can also help to diminish and thus possi- coumarins, which are found in many common fruits and veg- bly prevent the sequelae of .4 “Tincture of etables, such as limes, lemons, oranges, , fig, , time” and photoprotection are the most useful interventions , and carrots.1,2 If a -containing compound (e.g. for hyperpigmented lesions. Families must be counseled that it juice) lands on the skin and is then exposed to UVA of a may take months for such pigmentation to resolve. specific wavelength (320-400nm), a phototoxic compound is formed that can induce a variety of skin findings.3 Condition: ab igne Phytophotodermatitis is frequently seen in people who are Sour ce: hea t e xp osur e. active outdoors, beachgoers, and children who have been play- (EAI) is a localized cutaneous eruption that ing in the sun. occurs after chronic exposure to heat. In the past, EAI was a Within a few hours to days of exposure, patients can devel- common condition seen on the legs of women who stood or sat op erythematous plaques, vesicles, or bullae. Hyperpigmented too close to a fire, but in current times, the development of EAI patches without any preceding erythematous phase are also has been linked to space heaters, fireplaces, car heaters, and common. Skin lesions classically present with strange configu- even the use of laptop computers propped on the legs! It has rations and can appear in the shape of streaks or as finger marks also been known to develop after repeated application of hot corresponding to areas of sun-exposed skin that came into con- water bottles or heating pads used to treat chronic pain or

October 2008 Practical Dermatology 29 Exposure Dermatology

backaches.5 EAI occurs when exposure to heat is recurrent but It’s also important to keep in mind that often only one mem- acutely insufficient to cause a classic burn. ber of the family is affected.15 The typical initial manifestation of EAI after a single expo- To prevent papular urticaria, children are advised to wear sure is transient reticular erythema. With continued exposure protective clothing when playing outdoors. They can also use to heat, a more marked erythema with hyperpigmentation insect repellents to ward off mosquitoes and other arthropods. develops and occasionally superficial epidermal atrophy. However, parents should take care to avoid prolonged exposure Eventually, the skin becomes persistently erythematous with to high concentrations of pesticides, particularly in young chil- pigment changes, reticulate telangiectasia, and diffuse hyperk- dren. It is a good idea to spray clothing when possible rather eratosis.6 Subepidermal bullae are rare but have been report- than skin and resist the inclination for repeated, frequent dous- ed.7 Although lesions are typically asymptomatic, patients may ing with multiple sprays due to potential neurologic toxicities. describe burning or itching sensations. On rare occasions, Families with pets should ensure that their pets do not have squamous cell carcinoma and Merkel cell carcinoma have also fleas. There are a variety of flea solutions for animals, includ- been known to arise in the lesions.8,9 ing flea collars, flea shampoo, and flea medications specifical- Avoidance of chronic heat to any one site on the body is the ly designed for pets. Frequent bathing of the animal can also best preventative measure, and immediate removal of the be helpful in preventing fleabites. We also recommend check- source of heat is the maintstay of therapy for EAI. Early ing screens to avoid inadvertent entry points for mosquitoes. removal of the heat source results in an excellent prognosis To prevent bed bugs from colonizing the home, all bedding with spontaneous resolution over time. However, chronic and mattress pads should be laundered every two to four exposure without discontinuation can result in persistent pig- weeks. Also, applying double-sided tape to the legs of the bed mentary abnormalities, atrophy, or even malignancy. Some can actually help prevent bedbug infestation.16 Finally, if more reports have shown that 5-Fluorouracil cream is effective in conservative measures are ineffective, families can consider clearing epithelial atypia. Furthermore, it is important to per- professional pesticide treatments for their home. form a biopsy of the lesion if any evidence of cutaneous malig- In treating papular urticaria, most physicians have found nancy such as nodules or ulceration exists.10 that sparing use of high-potency topical steroids can be help- ful in reducing inflammation and controlling pruritus. Condition: Papular ur tic aria Antihistamines such as cetirizine, hydroxyzine, or diphenhy- Sour ce: Insec t bit es . dramine can also provide relief from itching in an acute set- Insect bite-induced hypersensitivity reactions, also known as ting, and sometimes are required for more prolonged use. papular urticaria, are a common dermatological complaint in Older children and adults with more localized papular the pediatric population, especially in urban environments. It urticaria may find intralesional steroids helpful in decreasing is most common in children age two to 10 but can occasion- pruritus, but it’s best to avoid this method in young patients ally occur in adolescents and is even seen in adults. Papular with widespread lesions.15 urticaria is caused by a hypersensitivity reaction to biting or Finally, although papular urticaria can be a frustrating and stinging insects, most commonly cat and dog fleas recurrent problem, patients should be reassured that even (Ctenocephalides felis and canis). However, other offenders without any treatment, they will eventually develop tolerance include mosquitoes and the common bedbug (Cimex lectular- to the insect bites and their symptoms will resolve. ius).12-14 True papular urticaria requires a long period of sensi- tization during which the patient is repeatedly exposed to the Condition: Aller gic c on tac t der m a titis insect. Fortunately, most children will develop tolerance to the Sour ce: P lan t e xp osur e insect bites by about 10 years of age.11 Four commonly encountered species of the Anacardiaceae plant The typical skin lesions of papular urticaria present as family (poison ivy, western poison oak, eastern poison oak, and recurrent eruptions of pruritic papules, vesicles, and wheals. poison sumac) account for the majority of allergic contact der- They are usually grouped into linear or triangular clusters on matitis seen in the United States. In fact, 50 to 70 percent of the exposed areas of skin such as the face, neck, arms, and legs. population is sensitized to the toxic effects of these plants!17 This The diaper area, palms, soles of the feet, and trunk are com- group of plants causes more allergic than all monly spared. Intense pruritus may occur, and scratching can other causes combined. Allergic contact dermatitis occurs after lead to excoriations, secondary infection, scarring, or perma- direct or indirect contact with the plant’s sap, which contains an nent pigmentation abnormalities.11 Other characteristics that allergenic component called urushiol. Uroshiol is also found in help distinguish papular urticaria from other pediatric rashes the leaves, stems, and roots of the plants. Direct contact with include a symmetric or sometimes “meal cluster” distribution. the sap results from touching or brushing against an injured

30 Practical Dermatology October 2008 1 2 3

4 5 6

7 Photo 1: Phytophotodermatitis. Friedlander, Rady Children’s Hospital Courtesy of Dr. Dohil, Rady Children’s Photo 5: Allergic Contact Dermatitis Hospital from Poison Oak. Courtesy of Dr. Barrio, Photo 2: Erythema Ab Igne. Courtesy of Rady Children’s Hospital Dr. Barrio, Rady Children’s Hospital Photo 6: Allergic Contact Dermatitis Photo 3: Papular Urticaria in an infant. from Poison Ivy. Courtesy of Dr. Barrio, Courtesy of Dr. Friedlander, Rady Rady Children’s Hospital Children’s Hospital Photo 7: Cutaneous Larva Migrans. Photo 4: Papular Urticaria in a child, Courtesy of Dr. Friedlander, Rady healing phase. Courtesy of Dr. Children’s Hospital

plant. Meanwhile, indirect contact may occur by a variety of poison oak. Poison sumac, though, possesses seven to 13 vehicles including clothing, shoes, tools, pets, and even smoke smooth-edged leaflets and glossy pale yellow or cream-colored from burning plants contaminated with the sap.18 Mango rind berries. Wearing protective clothing is another way to prevent also cross-reacts with these plants, and can cause a perioral der- exposure to these plants. An over-the-counter product called Ivy matitis after eating this fruit. Block, an organoclay preparation, has shown to be effective in Like papular urticaria, allergic contact dermatitis requires preventing reaction to uroshiol, as well.22,23 This lotion should be prior sensitization to induce skin lesions. Following first expo- applied to the skin at least 15 minutes before exposure and sure, it can take from seven to 21 days to develop lesions. forms a visible coating, but it needs to be reapplied at least every However, a previously sensitized individual will begin to devel- four hours for continual protection. op very intense pruritus and erythema within 24 to 48 hours, Once contact with the plant’s sap has occurred, the exposed followed by the appearance of papules, vesicles, and even bullae area should be washed thoroughly with mild soap and water to if severe.19 The lesions often develop in multiple, linear arrange- remove any remaining uroshiol. Since the uroshiol can remain ments that reflect the exposure (plant, twig, or scratching from on surfaces for a long time and cause further exposure, clothing a hand) and suggest an “outside-in” etiology. Untreated lesions and gear should also be removed as quickly as possible to pre- usually last two to three weeks. Secondary bacterial infection, vent any spread. If the uroshiol-containing sap is completely erythema multiforme, and urticaria may complicate the presen- removed from the skin within 10 minutes of contact, dermati- tation, but these are quite rare.20,21 tis usually does not develop.17 However, if dermatitis does devel- The famous rule “leaves of three, let it be” is a good guide- op, topical therapies are usually sufficient. For weeping lesions, line to follow when trying to avoid the leaves of poison ivy or cool compresses, dilute aluminum acetate soaks, and calamine

October 2008 Practical Dermatology 31 Exposure Dermatology

lotion can help reduce pruritis and dry the skin. High-potency Indec en t Exp osur e topical corticosteroids can be useful in the early phase of a local- Despite the best efforts of physicians and parents, children are ized rash. often prone to developing dermatologic conditions from expo- For severe or refractory allergic contact dermatitis, a course sures in their environment. However, preventative measures and of systemic corticosteroids should be administered,20 along with effective treatment options do exist for the skin conditions dis- frequent colloidal oatmeal baths and adjuvant oral antihista- cussed here, and with proper therapy, many of these manifesta- mines. It is important to avoid “short pulses” (four to six days) tions can be quickly and easily resolved without serious risk to of systemic therapy, as relapse may occur following discontinu- a child’s health. I ation of systemic therapy lasting less than seven to 10 days. Most experts recommend 1-2mg/kg/d of oral prednisone, The authors reported no relevant disclosures. tapered over two to three weeks.24 1. Egan CL, Sterling G. Phytophotodermatitis: a visit to Margaritaville. Cutis. 1993; 51:41-42. 2. Weber IC, Davis CP, Greeson DM. Phytophotodermatitis: the other “lime” disease. J Emerg Med.1999; Condition: Cutaneous lar va migr ans 17:235-237 3. Goskowicz MO, Friedlander SF, Eichenfield LF. Endemic “lime” disease: phytophotodermatitis in San Sour ce: Sand e xp osur e Diego Country. Pediatrics.1994; 93:828-830. Dermatitis caused by the invasion and migration of nematode 4. Solis RR, Dotson DA, Trizna Z. Phytophotodermatitis: a sometimes difficult diagnosis. Arch Fam Med. 2000;9:1195-1196 larva in the skin, cutaneous larva migrans (CLM) is most often 5. Tan S, Bertucci V. Erythema ab igne: an old condition new again. CMAJ 2000; 162(1):77-8. seen in frequent beachgoers and children who play in sandbox- 6. Kennedy CTC, Mechanical and Thermal Injury, Rook A, Wilkinson DS, Ebling FJG, eds, Textbook of es or soil. In the US, this condition usually results from contact Dermatology, 6th ed. Oxford: Blackwell Scientific Publications, 937-938, 1998. with soil or sand contaminated with animal feces that contains 7. Flanagan N, Watson R, Sweeney E, Barnes L. Bullous erythema ab igne [letter]. Br J Dermatol 1996; the eggs of dog or cat hookworms. Once in the soil, the hook- 134:1159-60. 8. Arrington JH, Lockman DS. Thermal keratoses and squamous cell carcinoma in situ associated with worm eggs hatch and release larvae that develop into an infec- erythema ab igne. Arch Dermatol. 1979;115:1226-8. tive form within a week’s time. These infective nematode larvae 9. Finlayson GR, Sams WM, Smith JG. Erythema ab igne: a histopathological study. J Invest Dermatol live in the top half-inch of the soil and penetrate through small 1966;46:104-8. 10. Sahl WJ, Taira JW. Erythema ab igne: treatment with 5-fluorouracil cream. J Am Acad Dermatol. fissures or hair follicles of the epidermis when they come into 1992:27:109-10. 25 contact with human skin. Areas most commonly affected are 11. Steen CJ, Carbonaro PA, Schwartz RA. Arthropods in dermatology. J Am Acad Dermatol. 2004; 50:819- those that remain in contact with the soil, such as hand, feet, 862 buttocks, and anogenital region. Although CLM lesions may 12. Cohen B. Pediatric Dermatology. Baltimore, MD: Elsevier Inc; 2005 13. Maunder JW. Papular Urticaria. In: Harper J, Oranje A, Prose N. eds. Textbook of Pediatric vary slightly in their clinical presentation depending upon the Dermatology. London, England: Blackwell Science; 2000:549-554 species of nematode responsible for the infection, they are all 14. Arlian L. Arthropod allergens and human health. Annu Rev Entomol. 2002;47:395-433 typically intensely pruritic. 15. Hernandez, RG, Cohen BA. Insect Bite-Induced Hypersensitivity and the SCRATCH Principles: A New The best method of preventing CLM is to avoid contact of Approach to Papular Urticaria. Pediatrics 2006;118:e189-e196. exposed skin to contaminated soil or sand. By wearing shoes, 16. Hwang S, Svoboda TJ, DeJong I, Kabesele K, Gogosis E. Bed Bug infestations in an urban environ- ment. Emerg Infect Dis. 2005;11:533-538 gardening gloves, and using a beach towel when lying on sand, 17. Fischer A. Poison ivy/oak dermatitis part 1: prevention-soap and water, topical barriers, hyposensi- one can decrease the chance of exposure to the larvae. In addi- tization. Cutis 1996; 57(6):384-386. tion, making sure that pets are dewormed can help reduce soil 18. Lee NP, Arriola ER. Poison ivy, oak, and sumac dermatitis. West J Med. 1999; 171(5-6):354-5. contamination, and keeping pets away from sandboxes or other 19. Fisher A. Poison ivy/oak/sumac part II: specific features. Cutis 1996;58(1):22-24 areas where children frequently play may be beneficial as well. 20. Baer R. Poison ivy dermatitis. Cutis 1990; 46(1): 34-36 Because humans are accidental hosts in which the larvae are 21. Cohen L, Cohen J. Erythema multiforme associated with contact dermatitis to poison ivy: three cases and a review of the literature. Cutis 1998; 62(3): 139-142 not able to complete their life cycle, the larvae typically die a few 22. Epstein W. Topical prevention of poison ivy/oak dermatitis. Arch Dermatol 1989; 125(4):499-501 weeks after invasion and the disease subsides.26 In the past, top- 23. Marks J, Fowler J, Sheretz E, et al. Prevention of poison ivy and poison oak allergic contact dermati- ical thiabendazole was used to treat CLM because it was effec- tis by quaternium-18 bentonite. Jam Acad Dermatol 1995; 33(2 Pt 1): 212-6 tive in killing the larvae. However, topical thiabendazole is no 24. Ivys T, Tepper R. Failure of a tapering dose of oral methylprednisolone to treat reactions to poison ivy. JAMA 1991; 266(10):1362. longer a favored therapy as it requires repeated application, is 25. Gilman RH. Intestinal nematodes that migrate through skin and lung, In: Strickland GT ed. Hunter’s known to cause irritant dermatitis, and was often followed by Tropical Medicine and Emerging Infectious Disease, 8th edn. Philadelphia: Sounders 2000: 730-735. recurrences.27 Currently, the drug of choice in treating CLM is 26. Katz R, Ziegler J, Blank H. The natural course of creeping eruption and treatment with thiabendazole. albendazole, at a dose of 400-800mg/day for one to seven Arch Dermatol 1965; 91:420-424. 28 27. Goldsmith J, Froese E. A note on cutaneous larva migrans and its treatment with topical thiabenda- days. This drug is a well-tolerated anti-helminthic which acts zole. S Afr Med J 1976; 50:253-255. against eggs, larvae, and adult stages of the helminthes. It has 28. Rizzitelli G, Scarabelli G, Veraldi S. Albendazole: a new therapeutic regimen in cutaneous larva been shown to relieve pruritus in three to five days and resolve migrans. Int J Dermatol 1997; 36:700-703. 29 29. Albanese G, Venturi C, Galbiati G. Treatment of larva migrans cutanea (creeping eruption): a com- cutaneous lesions by day five to seven days of treatment. parison between albendazole and traditional therapy. Int J Dermatol 2001; 40:67-71.

32 Practical Dermatology October 2008