Lumps under the skin can have a variety of causes, including lipomas, enlarged lymph glands, boils, neurofibromas, dermatofibromas and some cancers such as keratoacanthoma, according to WebMD and Patient.info. For example, lipomas are tumors made of soft tissue that occur singly or in small groups, explains WebMD. Swollen glands or lymph nodes appear as lumps on the neck during a viral infection such as a sore throat, as stated by eMedicineHealth.
Subcutaneous cysts and neurofibromas are also soft growths that manifest as single or numerous lumps that are usually harmless, reports WebMD. A subcutaneous skin cyst is a small area under the skin that is filled with pus or other fluids and occurs as a result of the clogging of the skin's oil glands. Other causes of numerous lumps under the skin include cherry angiomas and keratosis pilaris.
Cherry angiomas are small cherry-colored bumps that are visible on the torso and do not need to be treated unless they bleed or are visually prominent, according to BootsWebMD. Keratosis pilaris appears as numerous white or red bumps under the skin and is usually found on the thighs, buttocks, upper arms and the back, states BootsWebMD. However, the condition is painless and harmless.