Puzzling Purpuras: Tale of an Unusual Bruise

Your pediatric hematology colleague asks you to see a young boy with concerning bruising that may or may not be a malignancy or bleeding disorder.

The 7-year-old boy's "rash" is of 3 months' duration. Screening CBC was normal. Malignancy can not yet be ruled out.

Past medical history, family history, and review of systems are all non-contributory. The child is also completely asymptomatic.

Rash began as darkened areas around right ankle that slowly enlarged over 2-3 months.

Pertinent findings: Reddish-brown macular lesion over area of distal right fibula and ankle. Non-palpable petechiae on periphery of lesion.

Results of laboratory tests are all normal: CBC, platelets, bleeding time, PT/PTT, urinalysis.

The macular area appears as a reddish-brown "bruise" and is non-palpable.

Note the pin-head sized petechial lesions at the periphery of the involved area.

Possible diagnoses? Not a malignancy; not classic Henoch-Schonlein purpura; not fixed drug eruption; bruising is persistent...

Differential diagnosis: Schamberg disease. pigmented purpuric lichenoid disorder; purpura annularis telangiectodes (Majocchi disease); lichen aureus; atypical Henoch-Schönlein purpura; eczematoid-like purpura.

Schamberg disease is the answer.

Schamberg disease: one of the pigmented purpuras; all are considered capillaritis; hemosiderin-laden macrophages seen on histology.

Schamberg disease: benign, chronic, can occur at any age; 5 times more common in males; lesions are red-brown punctate ("cayenne pepper spots).

Schamberg disease: Occasionally pruritic; tends to be persistent with flare-ups.

The pigmented purpuras: Schamberg disease, pigmented purpuric lichenoid disorder (PPLD) of Gougerot and Blum; purpura annularis telangiectodes (Majocchi’s disease); lichen aureus; eczematid-like purpura of Doucas and Kapetankis (itching purpura).

Not all that looks like purpura IS purpura; detailed history/physical and appropriate labs plus basic understanding of the pigmented purpuras may help you ease family's anxiety.