12.1 Introduction
The most common allergic contact dermatitis (ACD) seen in adolescents is due to plants most commonly known as poison oak, poison ivy, or poison sumac. These plants are from the Toxicodendron species, and the lesions themselves are termed Rhus dermatitis. In this chapter, we also discuss nickel allergic contact dermatitis (Ni-ACD) based on its frequency. ACD is most often a delayed type IV hypersensitivity reaction.
12.2 Epidemiology
ACD can be seen ubiquitously. An individual comes in contact with an allergen, develops a hypersensitivity reaction, and subsequently, future exposure results in ACD.
It has been theorized that an increase in piercings has increased the occurrences of Ni-ACD. Nickel was named the “Contact Allergen of the Year” in 2008 by the American Contact Dermatitis Society. Nickel is found in jewelry, snaps, belt buckles, coins, pencils, paper clips, glasses frames, keys, and cell phones. Manufacturers in the United States have been encouraged to use only those products that adhere to the European Union guidelines for acceptable nickel release rates in order to combat the rising rates of nickel sensitization.
12.3 Clinical Findings
Rhus dermatitis lesions are most often noted in exposed areas. The patients will often present with a history of exposure and are noted to have erythematous (sometimes linear or patterned) papulovesicular lesions (Fig. 12.1). The lesions tend to be itchy.
Ni-ACD will be noted in specific area of exposure to nickel. The lesions are plaque like, however will sometimes develop crusting. Common areas are earlobes (Fig. 12.2), posterior neck, and the lower abdomen (Figs. 12.3 and 12.4). Widespread “id” reaction may be noted (Fig. 12.5).
Rhus dermatitis with linear lesions
Earlobe dermatitis from nickel exposure associated with piercing
Ni-ACD of lower abdomen from belt buckle
(a, b) Ni-ACD from glasses
Id reaction associated with Ni-ACD on abdomen
12.4 Laboratory
Nickel content can be tested using dimethylglyoxime. Patch testing can help distinguish Ni-ACD from other allergens.
12.5 Treatment
Treatment consists of avoidance of the offending allergen. Rhus dermatitis can be minimized by using clothing to cover the skin and cleansing skin as soon as possible after exposure has occurred.
Topical or systemic corticosteroids are useful for calming inflammation.
12.6 Prognosis
The sensitization tends to be persistent and hence patients should attempt allergen avoidance.