PPGS tends to affect young adults, typically during the spring and summer Affected patients often have low-grade fevers along with painful, symmetrically distributed, petechial papules There is often a sharp cutoff where the lesions stop The oral mucosa may be affected PPGS spontaneously resolves after approximately to weeks However, it is important to evaluate patients thoroughly in order to distinguish PPGS from more serious bleeding disorders, septicemias, or rickettsial disorders such as Rocky Mountain spotted fever Rare associations have included coincident mononeuritis multiplex and red cell aplasia concurrent with PPGS attributed to the underlying parvovirus B19 infection Unilateral Laterothoracic Exanthem Unilateral laterothoracic exanthem (ULE), also known as asymmetric periflexural exanthem, is a self-limited phenomenon attributed to a virus It is thought to be viral because a viral prodrome may be associated ULE occurs in community clusters, and patients generally not experience recurrences The condition is characterized by collections of blanchable pink macules, papules, and plaques originating in flexural creases such as the axillary, inguinal, or popliteal areas, which then extend unilaterally along the thorax and extremity ( Fig 70.17 ) Often, the eruption generalizes and becomes bilateral within several days Symptoms may include mild itching While many viral exanthems resolve spontaneously within to weeks, ULE is longer lasting, and often takes approximately month before it resolves Recognition of the condition can allow the clinician to provide reassurance and an anticipated time course to the family regarding the natural history of the condition It is interesting to note that infection with molluscum contagiosum can trigger a ULE-like eruption This reactive ULE-like phenomenon, however, is of often shorter duration and is typically responsive to topical steroid treatment, in contrast to ULE