Acute pruritic eruption on a child’s face and hands

The case

You are asked to evaluate a healthy 9-year-old girl with an itchy rash on her face, neck, and hands for a week. She had a similar eruption 1 month ago that resolved over several days. Although she has a history of poison ivy, her parents knew of no exposure. There was no history of new topical skin products. However, she had begun to eat more seasonal fruits recently, including strawberries, grapes, and mangos.

NEXT: What's the diagnosis?

Etiology/Epidemiology

The skin of the mango, a seasonal exotic fruit, is well known to trigger acute contact dermatitis in patients with preexisting contact allergy to poison ivy. Poorly defined plaques of erythema and edema on the girl’s face in this case (Figure 1) are explained by direct contact with the mango skin or with allergen on the patient’s fingers that directly contacted the mango skin. Linear plaques as seen around the mouth strongly support a contact etiology.

Contact dermatitis can be classified as either allergic or irritant. Allergic contact dermatitis, unlike irritant contact dermatitis, is a T-cell immune-mediated reaction that occurs in response to various allergens.¹ Allergic contact dermatitis attributed to poison ivy is caused by urushiol, an antigen found in the sap of the poison ivy plant Rhus Toxicodendron as well as in the sap of poison oak and sumac.² A chemically similar allergen present in the skin of mangos can produce a similar cutaneous reaction in sensitized individuals.

Other sources of antigens that cross-react with urushiol include the sap or skin of the cashew tree, ginkgo, the Indian marking nut, the Japanese lacquer tree, and the Brazilian pepper tree.² In a patient with previous poison ivy-induced contact dermatitis and recent mango consumption, allergic contact dermatitis to the skin of the mango is the most likely diagnosis.

Clinical findings

Acute onset of pruritic edematous papules and vesicles often in an asymmetric linear pattern with sparing of covered sites is the hallmark of an acute contact dermatitis.¹ Vesicular hand lesions in a patient with history of poison ivy dermatitis but no exposure to the plant should raise concern for possible contact with a cross-reacting allergen (Figure 2).

Differential diagnosis

The differential diagnosis for a pruritic erythematous eruption such as that presented in this case includes atopic dermatitis. The linear nature of the lesions as well as presence of vesicles, as seen in this patient, favor an acute atopic dermatitis. The face is commonly involved in atopic dermatitis with well-recognized stigmata including eyelid pleats (Dennie-Morgan lines), allergic shiners, and a transverse nasal crease.³

Next: Patch testing in atopic dermatitis

The presentation of atopic dermatitis can be similar to that of irritant contact dermatitis, both of which typically lack frank blister formation.³ However, irritant contact dermatitis, like allergic contact dermatitis, often presents in an asymmetric linear or geometric pattern with sharp demarcation from the surrounding unaffected skin. The presence of vesicles, linear lesions, and a known allergy to urushiol make allergic contact dermatitis from mango skin the most likely diagnosis.

Management

The management strategy for allergic contact dermatitis includes patient education, allergen avoidance, and treatment of acute flares with topical corticosteroids. When reactions are severe, widespread, or involve important areas such as the face, hands, and/or genitals, a 2-week tapering course of oral steroids may be considered.

Patient outcome

The patient was managed with twice-daily application of topical hydrocortisone 2.5% ointment for control of her acute flare and education was provided for avoiding exposure to allergens that may cross-react with urushiol.

ACKNOWLEDGEMENT:

The authors thank the patient’s family for granting permission to publish this information.

REFERENCES

1. Rycroft RJG, Menné T, Frosch PJ, Lepoittevin JP, eds. Textbook of Contact Dermatitis. Berlin: Springer Science & Business Media, 2013.

2. Chen HH, Sun CC. Patch testing with various mango (Mangifera indica) extracts. Clin Res Dermatol Open Access. 2014;1(1):1-3.

3. Spiewak R. Contact dermatitis in atopic individuals. Curr Opin Allergy Clin Immunol. 2012;12(5):491-497.