One of several pigmented purpuric dermatoses
Schamberg’s disease fits under the inclusive term of pigmented purpuric dermatoses (PPD), as a macular purpuric reddish-brown dermatosis. Other subtypes of PPD can be distinguished from Schamberg’s disease clinically. These subtypes include lichen aureus, which appears as golden patches; Majocchi’s purpura, which forms an annular pattern with telangiectasias; Gougerot-Blum purpura, which is associated with lichenoid dermatitis; and Doucas and Kapentanakis purpura, which is an eczematous variant. Other forms of purpura can be distinguished from Schamberg’s disease histologically (TABLE).3
Platelet abnormalities can also produce red, flat, nonblanchable petechiae, and may occur in patients who have taken certain prescribed drugs, over-the-counter medications, or herbal remedies; those who have received recent vaccinations; and in those who have (or have had) severe viral infections, beta-hemolytic streptococcal infections, leukemia, lupus erythematosus, or idiopathic thrombocytopenic purpura.
Scurvy can also cause perifollicular petechiae that are distributed primarily on the lower extremities and are symmetrical. Gums may be swollen or hemorrhagic, and patients will have a history of vitamin C deficiency, myalgia, and fatigue. Children may have bone tenderness, epistaxis, and hematuria. A diagnosis can be made by looking for low ascorbic acid in the serum. Prompt correction with vitamin C supplementation is also diagnostic.
Dysproteinemia can cause crops of petechiae and occasionally ecchymoses. Lesions appear on the lower extremities and sometimes on the ears and the tip of the nose. Cryoglobulinemia is associated with Raynaud’s phenomenon, cold urticaria, dizziness, and epistaxis; it is also associated with hepatitis C infection in >90% of cases.4 Macroglobulinemia is associated with dilated vessels and hemorrhage in the optic fundi, mental confusion, anemia, weight loss, hepatosplenomegaly, and lymphadenopathy. Hyperglobulinemic purpura may be associated with arthritis, xerostomia, anemia, and hepatosplenomegaly. These various dysproteinemias can be diagnosed by finding abnormal proteins through serum electrophoresis. Skin biopsy of the petechiae reveals thrombi in dermal vessels, which may be associated with leukocytoclastic vasculitis.4
Many viral infections may result in a petechial rash, including measles, rubella, hepatitis, cytomegalovirus, Coxsackievirus, and respiratory syncytial virus. Petechial rashes associated with eczema or seborrheic dermatitis-like lesions can also be seen in children with Langerhans cell histiocytosis
TABLE
Histologic spectrum of purpura3
| Histologic pattern | Diseases |
|---|---|
| Erythrocyte extravasation without perivascular inflammation or fibrin deposition | Thrombocytopenic purpura, senile purpura, steroid purpura, scurvy |
| Erythrocyte extravasation with lymphocytic perivascular infiltrate; no fibrin deposition | Lichen aureus; Schamberg’s, Majocchi’s, Gougerot-Blum, and Doucas and Kapentanakis purpuras |
| Erythrocyte extravasation with vascular damage, neutrophilic infiltrate, and fibrin deposition | Leukocytoclastic vasculitis, mixed cryoglobulinemia |