Arms hanging down and feeling a foreign body in the armpit is relatively common in clinical practice, considering that it is caused by pimples, enlarged lymph nodes, localized boils or carbuncles on the skin, women’s paratesticular breasts, lipomas, etc., and should be handled according to the situation. 1, pimples: it may be due to skin allergies, and common allergens such as pollens, dust mites, animal hair, seafood, etc., which can lead to many pimples on the skin or due to the localized skin. 2, pimple: it is easy to cause pimple on the skin because of long-term sweat and moisture, which can lead to pimple on the skin. Long-term sweat more, more humid, easy to cause the skin to grow pimples, which will appear arm hanging down to feel the armpit has a foreign body. For the allergy caused by the rash, it is recommended to apply compound dexamethasone acetate cream, for the small pimples caused by hot and humid skin, it can be given to the external use of glycerite lotion; 2, lymph node enlargement: the armpit is a more common part of the lymph nodes, the human body pectoral muscles, mammary glands, spine, upper limbs, the lymph nodes will be returned to this region, if there is an infection of the upper limbs, or the chest, and other local skin infections and tumors, due to lymph node If there are infections in the upper limbs, or local skin infections and tumors in the chest, the lymph nodes often return to this area, which can cause local lymph node enlargement, as well as the feeling of a foreign body in the armpit when the arm is hanging down. For the infection of this skin or related area, oral cephalosporin antibiotics, such as cefixime granules, are recommended. If there is a tumor, it is recommended to do a puncture biopsy to exclude metastatic enlargement of lymph nodes, and then actively perform surgical resection if necessary; 3. Localized boils or carbuncles: the folds of the skin of the underarm are more, which are prone to breeding bacteria, and the formation of single hair follicle or multiple hair follicle infections may lead to the formation of boils or carbuncles, which may also occur when the arm hangs down. The formation of single hair follicle or multiple hair follicle infections can lead to boils or carbuncles, and the feeling of having a foreign body in the armpit when the arm hangs down can also occur. For single hair follicle infection, it is recommended to disinfect the area with iodophor and use ichthyol ointment externally, for multiple hair follicle infection, it is also possible to use ichthyol ointment externally, and it is recommended to make early incision and drainage when there is local abscess formation, and give gauze to drain, and apply iodophor to disinfect the area, and then cover the wounds with gauze. 4, female paratesticular breasts: some women have paratesticular breasts in the outer side of the armpit and the paratesticular breasts may have hyperplasia, inflammation and other different conditions, which will also cause arm drop feeling of a foreign body. Different conditions may cause the arm to hang down and feel like there is a foreign object under the armpit. The paratesticular breast not only affects the appearance, but also has the possibility of malignant transformation, so after the paratesticular breast ultrasound diagnosis is clear, it is recommended to carry out surgical resection; 5. Lipoma: there may be the occurrence of lipoma under the armpit, presenting the form of a lump, the local growth of the foreign body sensation is more obvious, and there will be the case that the arm hangs down and feels that there is a foreign body under the armpit. For this kind of situation, if the lipoma is relatively large, it is recommended to perform surgical resection after the ultrasound is clear.