Acute myeloid leukemia (AML) is a cancer of the blood and bone marrow affecting the skin. Rashes may be a symptom or complication. They can indicate disease presence or activity.
Appearance and Types of AML-Related Rashes
AML rashes present diversely. They may appear as small bumps (papules), larger lumps (nodules), or thickened flat patches (plaques) that are skin-colored, red, brown, or purple. They occur on any part of the body, often on the head, neck, trunk, arms, and legs.
Leukemia cutis involves the direct infiltration of leukemic cells. These lesions are firm and range from flesh-colored to reddish or purplish-red.
Sweet’s syndrome, also known as acute febrile neutrophilic dermatosis, presents as tender, red-to-purple papules and nodules merging into plaques, often with fever. It commonly affects the upper extremities, face, and neck.
Why Skin Manifestations Occur in AML
AML skin manifestations arise from two mechanisms: direct cancer cell infiltration and immune reactions. Leukemia cutis occurs when malignant myeloid cells invade skin tissue and accumulate.
Conversely, paraneoplastic syndromes like Sweet’s syndrome develop from the body’s immune response to leukemia. In Sweet’s syndrome, abnormal activation and migration of neutrophils (a type of white blood cell) occur in the skin. This inflammatory reaction is a hypersensitivity response to the malignancy. Though immune cells infiltrate the skin, leukemic cells are not directly present.
Diagnosing and Interpreting the Rash
Diagnosis involves clinical examination and testing. Professionals inspect lesions, noting their appearance, duration, and symptoms. As AML rashes can resemble common skin conditions like eczema or psoriasis, definitive diagnosis requires further investigation.
A skin biopsy is the key diagnostic tool for confirming AML-related skin manifestations. During a biopsy, a tissue sample is removed and examined under a microscope.
For leukemia cutis, the biopsy reveals malignant leukemic cells infiltrating the dermis. For Sweet’s syndrome, the biopsy shows a dense infiltration of neutrophils without evidence of vasculitis.
A skin rash can indicate AML; rarely, leukemia cutis can be the first sign, preceding bone marrow involvement. It often indicates advanced disease or relapse.
Treatment of AML Skin Rashes
Treatment focuses on the underlying acute myeloid leukemia. Systemic treatments for AML, such as chemotherapy, targeted therapies, or stem cell transplantation, target the root cause. As leukemia responds to therapy, skin lesions improve or resolve.
Beyond systemic AML treatment, specific therapies manage rash symptoms and comfort. For leukemia cutis, localized radiation therapy treats limited lesions. For Sweet’s syndrome, corticosteroids are the standard treatment, leading to prompt symptom resolution. Topical or oral corticosteroids alleviate discomfort and inflammation. Antimicrobial medications prevent or treat skin infections, common in AML patients with compromised immunity.