A 25 -month-old girl presented with a 3-week history of a progressive pruritic eruption that began on the left lower abdomen, inguinal area, and anterior thigh. A few lesions subsequently appeared on the right side of her body.
Her history was negative for any recent illness. She had no systemic symptoms. Her medical history was unremarkable, and the family history was negative for skin disease.
On physical examination, she was well appearing and afebrile. Left sided serpiginous, erythematous, urticarial papules, and plaques, most confluent on the right proximal anterior lower extremity and inguinal area (Figure 1), were noted. The remainder of the examination was normal.
Figure 1. Photograph of the child's left lower extremity shows multiple erythematous, serpiginous, urticarial papules,and plaques.
This exanthem was reported in two case series in 1992 and 1993, and the names unilateral lateral thoracic exanthem1 (ULE) and asymmetric periflexural exanthem of childhood2 (APEC) were proposed, respectively, by the two groups. Although several investigators have proposed an infectious etiology, extensive evaluations for a viral or bacterial pathogen have not identified an agent.1'3,4
ULE has a female preponderance3'5 and may have an increased incidence in the spring. Laboratory examination is unremarkable, although lymphocytosis without atypical lymphocytes occasionally has been reported. Histologic features include a perivascular lymphocytic infiltrate with infiltration in and around the dermal eccrine ducts.3
The eruption may be preceded by a mild gastrointestinal or upper respiratory illness. Initial lesions are commonly noted in the axilla or inguinal area and local spread is typical. The eruption often generalizes after the local centrifigal spread. The morphology of the individual lesions is variable; urticarial, eczematous, and vesicular papules and plaques have been reported.
Plaques may become annular or serpiginous, and pruritus often is present. The eruption often lasts for several weeks3 but may be present for several months. Recurrence is rare. Treatment is symptomatic, and topical corticosteroids or systemic antihistamines may be of benefit.
1. Bodemer C, de Prost Y. Unilateral laterothoracic exanthem in children: a new disease? J Am Acad Dermatol. 1992;27(5 Pt l):693-696.
2. Taieb A, Megraud F, Legrain V, Mortureux P, Maleville J. Asymmetric periflexural exanthem of childhood. J Am Acad Dermatol. 1993;29(3): 391-393.
3. McCuaig CC, Russo P, Powell J, et al. Unilateral laterothoracic exanthem. A clinicopathologic study of forty-eight patients. J Am Acad Dermatol. 1996;34(6):979-984.
4. Harangi F, Varszegi D, Szucs G. Asymmetric periflexural exanthem of childhood and viral examinations. Pediatr Dermatol. 1995; 12(2): 112-1 15.
5. Laur WE. Unilateral laterothoracic exanthem in children. J Am Acad Dermatol. 1993;29(5 Pt 1): 799-800.