Pimples are a common skin concern, appearing as clogged pores filled with oil and dead skin cells. While many experience these blemishes, an unusual odor from a pimple can be unsettling. This characteristic is not typical for all breakouts. This article explains the scientific reasons why some pimples emit a distinct smell.
Understanding the Source of the Odor
The primary reason some pimples develop an odor lies in the activity of bacteria, particularly Cutibacterium acnes, which naturally reside on the skin. These bacteria thrive in oxygen-poor environments within clogged hair follicles, metabolizing sebum (the skin’s natural oil) and dead skin cells.
Volatile fatty acids (VFAs) and sulfur compounds are significant contributors to the odor. As C. acnes breaks down sebum, it produces these compounds, which can have distinct, often pungent smells, sometimes described as similar to onions, garlic, or rotten eggs. Inflammation within the pimple and the presence of pus can exacerbate the odor. Pus consists of dead white blood cells, bacteria, and tissue debris, which can trap and concentrate these odorous byproducts, leading to a more noticeable smell when the pimple’s contents are released.
Pimple Types Prone to Odor
Certain pimple types are more likely to produce an odor due to their depth, severity, and the environment they create for bacterial growth. Deeper, inflamed lesions provide ideal conditions for the anaerobic bacteria responsible for the smell.
Cystic acne, for example, involves large, painful, pus-filled lesions deep under the skin. These deep-seated cysts offer an enclosed, oxygen-deprived space where C. acnes can flourish and produce a significant amount of odorous compounds.
Nodules, which are hard, painful lumps beneath the skin, can also become odorous if severely inflamed or infected. Like cysts, nodules create a deep pocket where bacteria multiply and generate foul-smelling substances.
Large, inflamed whiteheads or pustules, particularly if ruptured or picked, can also release trapped material with an unpleasant smell. Epidermoid cysts, non-cancerous bumps under the skin filled with a thick, cheesy keratin substance, are also noted for sometimes producing a distinct odor.
Strategies for Prevention and Management
Consistent skincare practices help prevent and manage odorous pimples by reducing contributing factors. Gentle cleansing twice daily removes excess oil, dead skin cells, and surface bacteria without irritation. Use a mild, non-abrasive cleanser to avoid stripping natural oils, which can lead to increased sebum production.
Avoid picking or squeezing pimples, as this can push bacteria deeper, worsen inflammation, and release trapped, odorous contents. Topical treatments like salicylic acid or benzoyl peroxide can also be integrated into a skincare routine. Salicylic acid exfoliates and unclogs pores, while benzoyl peroxide targets acne-causing bacteria and reduces oil. General hygiene practices, such as washing pillowcases regularly and minimizing touching the face, can also reduce the transfer of bacteria and oils to the skin.
When to Consult a Dermatologist
Consult a dermatologist if odorous pimples persist or worsen despite consistent home care. Large, painful, or deep-seated lesions like cysts and nodules often require professional intervention, as they can lead to scarring. Signs of a more severe infection, including spreading redness, significant pain, or fever, require immediate medical evaluation.
A dermatologist can accurately diagnose the acne type and recommend appropriate treatments beyond over-the-counter options. These may include stronger topical medications, oral antibiotics, or other procedures to manage severe or persistent cases and address scarring or emotional distress.