**4. Utility of patch testing**

With increasing recognition of allergic contact dermatitis in the pediatric population, patch testing is becoming more important in this age group. Relative to the total number of studies investigating the prevalence of positive patch testing, those which address clinical relevance of results are fewer. However, a number of epidemiologic studies reflect upon the significance of positive tests, supporting the use of this diagnostic modality in pediatrics. In 1989, Kuiter reported that over 23% of positive tests were clinically relevant, while

gunbelt holster. The term 'Lucky Luke' is used to describe this entity that has been attributed to MBT, BPF (Roul et al., 1998) and recently cyclohexylthiophathalimide, which is

Plants, particularly those of the Rhus family, are often thought of in the context of allergic contact dermatitis, though they are infrequently within the top five allergens detected in children (Table 1). Up to 85% of the population is sensitized to plants within the Toxicodendron genus, which includes poison ivy, and most patients are sensitized between ages 8 and 14 years old (Koo et al., 2010). Plant allergy can often be identified by history and distribution generally at exposed sites. *Rhus verniiciflua* (Japanese lacquer tree) has been reported in children to cause severe allergic contact dermatitis, which can be mistaken for cellulitis. Many reported patients required systemic steroids due to severity of rash (Gach et

Compositae (Asteraceae) is the second largest plant family and is a well-recognized cause for contact allergy in gardeners, florists and farmers due to the sesquiterpene lactone component. For some time, it was rarely considered a clinically relevant allergen in children. However, there are several cases described in the literature. Flohr and colleagues described hand dermatitis in three children aged 3-8 years old, each of whom had frequent exposure to plants and tested positive to Compositae (Flohr et al., 2008). Paulsen et al. suggest that this particular allergy may be more common in atopic patients (Paulsen et al., 2008.) and Belloni Fortina et al. propose it should be added to the pediatric screening series when investigating airborne dermatitis in atopic children. They made this recommendation after finding 12 of 641 children sensitized to this antigen (Belloni Fortina

Henna (*Lawsoniainermis*) is a plant from the Lythraceae family. Henna dye is a dark green powder made from the leaves of this plant and used for hair dyeing and for temporary body tattooing. PPD is added to henna dye in order to make the color darker and speed the dyeing process (Jovanovic & Slavkovi-Jovanovic, 2009). This tattooing practice is becoming more popular in the pediatric population. PPD is a potent sensitizer and the literature is peppered with case reports regarding sensitization to PPD after henna tattooing in children (Jovanovic & Slavkovi-Jovanovic, 2009; Sidwell et al., 2008). As this exposure is becoming more prevalent in the pediatric population, some are calling for increased regulations

With increasing recognition of allergic contact dermatitis in the pediatric population, patch testing is becoming more important in this age group. Relative to the total number of studies investigating the prevalence of positive patch testing, those which address clinical relevance of results are fewer. However, a number of epidemiologic studies reflect upon the significance of positive tests, supporting the use of this diagnostic modality in pediatrics. In 1989, Kuiter reported that over 23% of positive tests were clinically relevant, while

used as a vulcanization retarder in rubber (Belhadjali et al., 2001).

**3.2.6 Henna tattoos with para-phenylenediamine (PPD)** 

**3.2.5 Plants** 

et al., 2005).

(Sidwell et al., 2008).

**4. Utility of patch testing** 

al., 2006; Rademaker & Duffill, 1995).

Rademaker purported that the value was as high at 92% (Kuiters et al., 1989; Rademaker et al., 1989). A review of studies that report on relevance suggests that the value is probably around 60% (Table 1). Many authors specifically endorse the use of patch testing in children (Jacob et al., 2008; Worm et al., 2007). In the past, it was recommended that the concentration of patch tests be reduced in children (Fisher, 1975; Hjorth, 1981). For example, Fisher recommended using half the recommended concentration (Fisher, 1975). This was due the concern that children are at higher risk of developing irritant reactions and thus, false positive tests (Mortz & Andersen, 1999). However, recent studies suggest that the incidence of irritant reactions is low. Brasch and Geier reported a 9% incidence of irritant reactions (Brasch & Geier, 1997). Most experts recommend the use of the same allergen concentration in children as in adults (Brasch & Geier, 1997; Mortz & Andersen, 1999; Roul et al., 1997; Worm, 2006).

Multiple groups recommend abbreviated series in children, in part due to smaller body surface area of normal skin on which to perform the testing. The German Contact Dermatitis Research Group suggests that in children aged 6-12 years old, the following allergens should be tested: nickel sulfate, thiuram mix, colophony, mercaptobenzothiazole, fragrance mix I, fragrance mix II, mercapto mix, bufexamac, dibromodicyanobutane, chlormethylisothiazolinone, neomycin and Compositae mix. Potassium dichromate, wool alcohols, disperse blue mix, para-phenylenediamine and *p-tert*.-butylphenol-formaldehyde resin may be added if clinically indicated (Worm et al., 2007). Brasch and Geier advocate for a shorter series that includes nickel, cobalt, dichromate, thimerosal, fragrance allergens, wool wax alcohols and Kathon CG. Their analysis was conducted in Germany, and they suggest that since different geographic locations may show varying rates of sensitization to allergens, local experience should be considered when choosing patch testing series for children (Brasch & Geier, 1997). Finally, Seidenari et al. advise clinicians to use patch testing in children but warn that due to frequent changes in relevant allergen exposures, periodic evaluations of the appropriate testing trays should be done for the pediatric population (Seidenari et al., 2005).

Of note, it should be mentioned that while patch testing often yields positive results to relevant allergens, it is unclear that finding a positive allergen is associated with improved clinical outcome. This is generally due to lack of data. Moustafa et al. recently published retrospective data supporting the relevance of positive patch tests in 44% of 110 children. Unfortunately, finding a positive allergen was not associated with improved clinical outcome in this population (Moustafa et al., 2011).

In adults, it has been shown that performing delayed patch test readings often yields more positive results. Matiz and colleagues have recently proposed that this is true in children as well. In 38 children aged 6 -17 years old, patch tests were evaluated after 48 hours, 72-96 hours and again at 7-9 days. 50% of children revealed positive reactions at the 7-9 day mark and 13% of the total number of children revealed new late delayed reactions. 4 of 6 late delayed allergens were considered clinically relevant including quaternium 15, formaldehyde, diazolidinyl urea and *p-tert*-butylphenol formaldehyde resin (Matiz et al., 2011). While this may not be a feasible approach to patch testing in all patients, it is a useful pearl in children for whom a diagnosis of allergic contact dermatitis is highly suspected.

Contact Dermatitis in Children 143

Andersen KE, Hjorth N, Menne T. The baboon syndrome: systemically-induced allergic

Andersen KE, Jensen CD. Long-lasting patch reactions to gold sodium thiosulfate occur frequently in healthy volunteers. Contact Dermatitis. 2007; 56: 214-7. Angelini G, Meneghini CL. Contact and bacterial allergy in children with atopic dermatitis.

Avenel-Audran M, Dutarte H, Goossens A, Jeanmougin M, Comte C, Bernier C, et al.

Ayala F, Balato N, Lembo G, Patruno C, Tosti A, Schena D, et al.A multicenter study of

Balato N, Lembo G, Patruno C, Ayala F. Patch testing in children. Contact Dermatitis. 1989;

Barros MA, Baptista A, Correia TM, Azevedo F. Patch Testing in children: a study of 562

Beattie PE, Green C, Lowe G, Lewis-Jones MS. Which children should be patch tested?

Bedi MK, Shenefelt PD. Herbal therapy in dermatology. Archives of Dermatology. 2002; 138:

Belhadjali H, Giordano-Labadie F, Rance F, Bazex J. "Lucky Luke" contact dermatitis from

BelloniFortina A, Romano I, Peserico A. Contact sensitization to Compositae mix in children. Journal of the American Academy of Dermatology. 2005; 53: 877-80. Bonitsis NG, Tatsioni A, Bassioukas K, Ionnidis JPA. Allergens responsible for allergic

Brasch J, Geier J. Patch test results in schoolchildren. Results from the Information Network

Bruckner AL, Weston WL, Morelli JG. Does Sensitization to Contact Allergens Begin in

Bruckner AL, Weston WL. Allergic contact dermatitis in children: a practical approach to

Carbone A, Siu A, Patel R. Pediatric Atopic Dermatitis: A Review of the Medical

Chu C, Sun C. Allergic contact dermatitis from triethanolamine in a sunscreen. Contact

Clayton TH, Wilkinson SM, Rawcliffe C, Pollack B, Clark SM. Allergic contact dermatitis in

Conti A, Motolese A, Manzini BM, Seidenari S. Contact sensitization to preservatives in

children: should pattern of dermatitis determine referral? A retrospective study of 500 children tested between 1995 and 2004 in one U.K. center. British Journal of

Management. The Annals of Pharmacotherapy. 2010; 44: 1448-58.

contact dermatitis among children: a systematic review and meta-analysis. Contact

of Departments of Dermatology (IVDK) and the German Contact Dermatitis

Octocrylene, an emerging photoallergen. Archives of Dermatology. 2010; 146: 753-

contact sensitization in children .Gruppo Italiano Ricerca Dermatiti da Contatto e

contact dermatitis. Contact Dermatitis. 1984; 10: 97-100.

Embientali (GIRDCA). Contact Dermatitis. 1992; 26: 307-10.

schoolchildren. Contact Dermatitis. 1991; 25: 156-9.

Clinical and Experimental Dermatology. 2007; 32: 6-11.

diapers: a new allergen? Contact Dermatitis. 2001; 44: 248.

Research Group (DKG). Contact Dermatitis. 1997; 37: 286-93.

Contact Dermatitis. 1977; 3: 163-7.

7.

20: 305-7.

232-42.

Dermatitis. 2011; 64: 245-57.

Infancy? Pediatrics. 2000; 105: e3.

Dermatitis. 2001; 44: 41-2.

Dermatology. 2006; 154: 114- 7.

children. Contact Dermatitis. 1997; 37: 35-6.

management. Skin Therapy Letter. 2002; 7: 3-5.


Table 4. Patterns of Localization of Allergic Contact Dermatitis and Their Respective Allergens.
