Healthy skin is typically smooth across most of your body. However, the skin is constantly bombarded by both the external environment as well as the internal functions of your body. As such, it is not uncommon for lumps and bumps to develop on the shoulders either directly on to of the surface, as with the case of moles or acne pustules, or beneath the surface of the skin, such as with cysts.
Infection Related Causes
A large portion of bumps that can develop on the shoulder are related to infections of bacteria or viruses. For example, acne pustules or cysts can often develop on the shoulders due to follicles being infected by the Propionibacterium acne bacteria. Boils can develop as bumps on the skin due to infection with the bacteria Staphylococcus aureus. In rare cases, bumps may occur on the skin due to viruses, such as measles or chickenpox.
Bumps can also develop from multiple other causes. For example, a bump on the shoulder may be a simple mole that develops due to alteration of melanocytes in the skin, or hives from a reaction to an irritant or allergen. Bumps can also develop due to an allergic skin condition such as hives, angiodema, contact dermatitis or eczema. A bite by an insect may also cause bumps to develop on the skin due to the production of histamine in the bite area. In rare cases, the formation of shoulder bump may be associated with the development of skin cancers like melenoma, especially when the bump is irregularly shaped or colored.
The effects of a bump on the shoulder can vary depending on the cause and location of the bump. For example, if the bump is infected, it may be quite painful. If the bump is on an area of the shoulder that meets with the seams of a shirt or the strap of a garment, friction can occur, further aggravating and irritating the bump.
Treatments for shoulder bumps can vary widely. For example, bumps related to acne cysts may be injected with steroids like hydrocortisone to reduce inflammation-related pressure. Other bumps may be drained using a sterilized needle. For irritating bumps, or bumps that may possibly be cancerous or pre-cancerous, your doctor may choose to surgically remove the bump from the skin.
Although many bumps that develop on or under the skin are harmless, there is still the rare possibility that they may be dangerous, such as in the case of a severely inflamed acne cyst, which can create severe scar tissue if left untreated, or in the case of a pre-cancerous or malignant bump. Irregular bumps on your shoulders should be examined by your doctor to ensure proper treatment and your safety.