Itchy armpits are likely caused by a non-cancerous condition, such as poor hygiene or dermatitis. But in some cases the itch can be a sign of lymphoma or inflammatory breast cancer.

Lymphoma is a cancer of the lymphatic system. It can cause swelling of the lymph nodes, commonly in the underarms, groin, or neck.

Lymphoma can cause swelling of the lymph nodes, commonly in the underarms, groin, or neck.

Hodgkin’s and non-Hodgkin’s lymphoma

While there are more than 70 types of lymphomas, doctor’s typically divide lymphomas into two categories: Hodgkin’s lymphoma and non-Hodgkin’s lymphoma.

About of people with Hodgkin’s lymphoma and of people with non-Hodgkin’s lymphoma are affected by itching. This is referred to as Hodgkin itch or paraneoplastic pruritus.

Hodgkin itch typically is not accompanied by an obvious skin rash.

T-cell and B-cell skin lymphoma

T-cell and B-cell skin lymphoma can produce a rash that accompanies the itch. This can have characteristics that include:

  • mycosis fungoides, which are small patches of dry, red skin that may resemble psoriasis, eczema, or dermatitis
  • skin hardening and thickening, as well as the formation of plaques that may itch and ulcerate
  • papules, which are raised areas of skin that may eventually grow and form nodules or tumors
  • erythroderma, which is a general reddening of the skin that can be dry, scaly, and itchy

Breast cancer is cancer that develops in the breast cells. A rare form of breast cancer called inflammatory breast cancer can cause symptoms that may include itching.

If your breast is tender, swollen, red, or itchy, your doctor might first consider infection rather than inflammatory breast cancer. The treatment for infection is antibiotics.

If antibiotics do not make the symptoms better in a week to 10 days, your doctor may perform tests for cancer, such as a mammogram or breast ultrasound.

Although itchiness, including in your armpit, can be a symptom of inflammatory breast cancer, it’s typically accompanied by other noticeable signs and symptoms. This can include:

  • skin changes such as thickening or pitting that gives breast skin the look and feel of orange peel
  • swelling that makes one breast look larger than the other
  • one breast feeling heavier and warmer than the other
  • one breast with redness that covers more than one-third of the breast

Your itchy armpits are likely caused by something other than cancer. Common causes include:

  • Poor hygiene. Bacteria will grow in places that collect dirt and sweat. To prevent itchy armpits, keep your underarms clean, especially after physical activity.
  • Dermatitis. Allergic, atopic, or contact dermatitis are all potential skin conditions that could appear in your armpits and create itchiness.
  • Chemicals. Your soap, deodorant, or laundry detergent could be triggering the itch in your underarms. Consider changing brands or using a natural alternative.
  • Prickly heat. Also known as heat rash and miliaria rubra, prickly heat is a bumpy, red rash sometimes experienced by people who live in humid and hot environments.
  • Dull razor. Shaving with a dull razor or without shaving cream can result in armpit irritation, dryness, and itchiness.
  • Hyperhidrosis. A disorder of the sweat glands, hyperhidrosis is characterized by excessive sweating that can lead to irritation and itch.
  • Bras. Some women have an itchy allergic reaction to bras made with nickel, rubber, or latex.
  • Intertrigo. Intertrigo is a rash in the skin folds. If left untreated, it can cause bacterial or fungal infection. High risk for intertrigo includes heat, high humidity, poor hygiene, diabetes, and obesity.

If your armpits are itchy, it’s likely caused by a non-cancerous condition such as poor hygiene, dermatitis, or an allergic reaction.

In most situations, if cancer is behind the itch, there are other symptoms accompanying it. This can include swelling, redness, warmth, and skin changes like thickening and pitting.

If you think your itchy armpits may be indicative of cancer, talk to your doctor. After a diagnosis, your doctor can recommend treatment to address any underlying conditions that caused the itchiness.