It can be quite perplexing and even a bit unsettling to discover that a pimple has an odor, especially one reminiscent of cheese. While it might seem unusual, this phenomenon is a relatively common concern for many individuals. The distinctive “cheesy” smell often arises from the breakdown of certain organic materials within the blemish itself. This process involves a combination of the skin’s natural secretions and the activity of resident bacteria.
The Science Behind the Scent
The skin naturally produces sebum, an oily substance from sebaceous glands that helps moisturize and protect the skin. When pores become clogged, a mixture of sebum and dead skin cells can accumulate, creating an environment where certain bacteria thrive. One prominent bacterium involved is Cutibacterium acnes, previously known as Propionibacterium acnes, which resides deep within hair follicles.
These bacteria are anaerobic, meaning they grow in low-oxygen environments, such as a blocked pore or a developing blemish. Inside this confined space, Cutibacterium acnes metabolizes the triglycerides present in sebum. This metabolic process breaks down the lipids into various byproducts, including free fatty acids.
Among these free fatty acids, some are highly volatile, meaning they easily become airborne and detectable by smell. Butyric acid, for instance, is a short-chain fatty acid known for its strong, pungent odor often described as rancid butter or cheese. The presence of sulfur compounds, also produced during bacterial decomposition of organic matter, can further contribute to the distinct, sometimes unpleasant, scent emanating from a blemish.
Types of Blemishes That Can Smell
While typical superficial whiteheads or blackheads usually do not produce a noticeable odor, deeper or more inflamed skin lesions are more likely to emit a “cheesy” scent. This is primarily because these larger blemishes offer a more confined, anaerobic environment conducive to bacterial activity and the accumulation of their metabolic byproducts.
Cystic acne lesions are deep, painful, pus-filled nodules that form beneath the skin’s surface. When these lesions rupture or are expressed, their contents, rich in volatile fatty acids, can release a strong, distinct odor.
Sebaceous cysts, also known as epidermoid cysts, are non-cancerous bumps that form when dead skin cells and keratin accumulate beneath the skin. The sac’s contents can be thick, yellowish, and have a cheesy consistency with a characteristic odor.
Boils, or furuncles, and larger abscesses are localized infections that fill with pus. While their odor is generally foul due to pus and necrotic tissue, they can also contain bacterial byproducts that contribute to a pungent smell.
When to Seek Professional Advice
While a “cheesy” smell from a pimple might simply be a byproduct of natural processes, certain accompanying symptoms indicate that professional medical attention is warranted. It is advisable to consult a healthcare provider if the blemish exhibits signs of a worsening infection or does not improve with time.
Consult a healthcare provider if you experience increasing pain, redness, or swelling around the affected area. Other signs include warmth to the touch, or systemic symptoms like fever or chills, which indicate a spreading infection.
Professional guidance is also recommended for blemishes that do not heal, worsen, or are recurrent. Large, deep lesions, especially cystic acne, often require intervention to prevent scarring and manage discomfort. A dermatologist or general practitioner can diagnose the lesion and recommend treatments, such as drainage, antibiotics, or other specific therapies.