Cutaneous leukemia is characterized by red or purple slightly elevated papules or nodules; patients with cutaneous myelofibrosis may also develop red or purple slightly elevated papules or nodules. Cutaneous leukemia is a malignancy of the white blood cells in the blood and is characterized by diffuse infiltration of the bone marrow by immature leukocytes and abnormal numbers of immature leukocytes in the blood. In addition, immature leukocytes often infiltrate extensively the liver, spleen, lymph nodes and other organs, including the skin. Cutaneous myelofibrosis, also known as cutaneous extramedullary hematopoiesis, is a chronic myeloproliferative disease. So what is the differential diagnosis of red or purple, slightly elevated papules or nodules? Here’s what you need to know. Differential diagnosis of red or purple, slightly elevated papules or nodules: 1. Corniform papules: Corniform papules can be triggered by a variety of etiologies and are a concomitant symptom of a variety of diseases. It is called white acne or milia white moss. It is a benign swelling or retained cyst originating from the epidermis or epithelium of the appendages. It can occur at any age or gender and is also seen in newborns. Post-traumatic papules often occur after abrasions, scratching or inflammatory facial eruptions. It is common in lesions of epidermolysis bullosa or epidermolysis bullosa and can also occur after herpes zoster blisters, and some patients have a genetic component. Acne is a skin condition that occurs when oily, dead epidermal cells clog your pores. Some people call it blackhead acne, milia, or pimples. Facial milia, a scattered, round, non-breaking papule on the face that leaves atrophic scars after healing. 2. maculopapular rash: a chassis with redness of the skin combined around the papule is called maculopapular rash. 3, cyanotic papules: Kaposi’s sarcoma skin damage is red, purple-red, light blue-black, cyanotic papules or plaques, gradually increasing in size and fusing into large plaques, nodules, nodules hard as rubber.