Mycosis Fungoides: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Mycosis Fungoides?
A dermatologist (a skin doctor) often finds and diagnoses mycosis fungoides. A hematologist or oncologist (a doctor who treats blood cancers and lymphomas) often helps lead treatment. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is mycosis fungoides?
Mycosis fungoides is the most common form of a type of blood cancer called cutaneous T-cell lymphoma. In this cancer, T cells, a kind of white blood cell, become cancerous and affect the skin. The skin cells themselves are not cancerous.
The disease is rare. It occurs in about 1 in 100,000 to 350,000 people. It may progress slowly through several stages, but not everyone goes through all of them.
Symptoms
Most people first get skin lesions called patches. These are flat, scaly, pink or red areas that can be itchy. Patches are most common on the lower belly, upper thighs, buttocks, and breasts. They can disappear and come back, or stay the same over time.
Early patches can look like other skin problems, such as psoriasis or eczema. The National Cancer Institute says an early scaly red rash may last for months or years. It is hard to diagnose as mycosis fungoides in this phase.
Some patches turn into plaques. Plaques are raised lesions that are usually reddish, purplish, or brownish and itchy. Not everyone with patches or plaques gets tumors.
Tumors are raised nodules that are thicker and deeper than plaques. Open sores may form on the tumors, which often leads to infection.
Rarely, the cancerous T cells spread to other organs, such as the lymph nodes, spleen, liver, and lungs.
Causes and who gets it
The cause of mycosis fungoides is unknown. Most affected people have chromosomal abnormalities, which are changes in the DNA. These changes happen during a person's life and are found only in the cancer cells.
Other factors, such as environmental exposure or certain infections, may be involved. Their influence is still unclear.
It usually occurs in adults over age 50, although children can be affected. It affects males nearly twice as often as females, for unknown reasons.
It is typically not inherited. People with this cancer have a higher risk of another lymphoma or another type of cancer.
How doctors diagnose it
Tests that look at the skin and blood are used. The doctor does a physical exam and asks about your health history.
A skin biopsy, which is the removal of cells or tissue to study under a microscope for signs of cancer, is used. More than one skin biopsy may be needed.
Blood tests can include a complete blood count and a count of Sézary cells, which are cancerous T cells in the blood.
If mycosis fungoides is found, other tests check whether it has spread. A lymph node biopsy removes all or part of a lymph node to check it for cancer.
Treatment
Mycosis fungoides is hard to cure. Treatment is usually meant to relieve symptoms and improve quality of life. The treatment choice depends on the stage of the cancer and the type of lesion.
Standard treatments include light therapy, radiation therapy, chemotherapy, other drug therapy, immunotherapy, targeted therapy, and stem cell transplant.
Light therapy uses ultraviolet A or B light on the skin. In one type, a medicine called psoralen is given first. People who have photodynamic therapy need to limit their time in sunlight.
Some chemotherapy is put on the skin as a cream, lotion, or ointment. Steroid creams are used to relieve red, swollen, inflamed skin.
Treatment may cause side effects. People may also think about joining a clinical trial, which is a research study of new treatments.
When to see a doctor
A red rash on the skin is a sign of mycosis fungoides. The National Cancer Institute says to check with your doctor if you have a scaly red rash, a thin reddened rash like eczema, raised bumps or hardened lesions, or tumors on the skin.
If you have mycosis fungoides, tell your care team if a sore opens on a skin tumor. Open sores on tumors often lead to infection.
Call 911 or go to the emergency room if you have trouble breathing, chest pain lasting two minutes or more, fainting, or confusion.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care doctor can look at a rash that does not go away, refer you to a dermatologist for a biopsy, and help coordinate your care with cancer specialists.
Common questions
Is mycosis fungoides a fungal infection?
No. It is a type of cutaneous T-cell lymphoma, which is a blood cancer that affects the skin. The name comes from tumors that can look like mushrooms.
Can mycosis fungoides be cured?
It is hard to cure. Treatment is usually meant to relieve symptoms and improve quality of life. People with early-stage disease may live many years.
Does mycosis fungoides always get worse?
Not always. It may progress slowly through several stages, but not all people go through all stages. Patches can stay stable over time.
Can mycosis fungoides spread to other parts of the body?
Yes, but this is rare. It can happen in any stage but is most common in the tumor stage.
Does mycosis fungoides run in families?
Usually not. It most often occurs in people with no family history and is typically not inherited.
Sources
- MedlinePlus Genetics - Mycosis fungoides
- National Cancer Institute - Mycosis Fungoides (Including Sezary Syndrome) Treatment (PDQ)
- NORD - Mycosis Fungoides
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
