Suction purpura.

A 50-year-old male presented with four ring-shaped purpuric lesions over the upper back [Figure 1] following interferential vacuum electrotherapy for acute pain in his neck and upper back. These patterned lesions corresponded to the site of application of the vacuum cups [Figure 2]. The patient was otherwise in good general health and not on any anticoagulant therapy. The lesions subsided spontaneously in 1 week's time.

Figure 1

Four rings of purpura due to vacuum interferential therapy on the upper back and neck

Figure 2

Interferential therapy unit with four circular vacuum cups

Purpuric eruptions due to local mechanical causes are commonly seen, particularly in children.[1] Localized suction to the skin usually produces either blisters or purpura. Suction purpura results from an external force exerting negative pressure on a circumscribed area of the skin, and may either take the form of petechiae or, if the injury is over a large surface area, an ecchymosis. Bizzare patterns of purpura may be caused by suction. Some of the examples where suction purpura can be seen include use of vacuum extractors, electrocardiogram leads, gas masks, therapeutic cups, toy arrows with sucker-shaped rubber ends, rubber suckers on children's toys (“sucker daddy syndrome”), vacuum cleaner and bath mat with cup-shaped indentations. Besides these, some of the other activities which could lead to these lesions are sucking on a cup, sucking on arms, sucking while kissing (love bite) and getting stuck in a bath tub.[2]

Therapeutic cupping,[3] a widespread folk medicine practice, particularly in Oriental countries and in some parts of eastern Europe, performed on patients with febrile illnesses can produce a similar pattern of purpura. The edge of the cup is warmed and applied to the patient's back. Suction is produced when the cup cools. The visible effect is a round area of ecchymosis, often with petechiae at the border.

These eruptions need to be recognized as isolated purpura and the patient should not be subjected to an unnecessary extensive hematologic workup. The lesions usually fade away completely within a few days.[1]