The eyelid can be subject to various lumps and bumps, some of which are harmless and no more than a cosmetic concern, and others which need to be seen by an oculoplastic surgery specialist immediately for treatment. When it comes to common eyelid bumps, one of the most frequent confusions is what is the difference between a chalazion vs a stye.
The human eyelid is much more than a simple fold of skin lined with eyelashes. Understanding a little about our own eyelid anatomy can help before moving into distinguishing between a chalazion vs stye, as these two eyelid bumps arise from different locations in the eyelid.
Within the eyelid beneath the visible skin are layers of smooth muscle, connective tissue, fibrous tissue, conjunctiva, and various secretory glands. An important set of glands are known as the meibomian glands, which line the eyelid margins on both the upper and lower lids. These glands produce an oily secretion commonly known as meibum, which functions to lubricate the surface of the eye and plays a crucial role in preventing dry eye. If you were to turn the eyelid inside out and examine the pink inner surface of conjunctiva with the appropriate imaging technology, healthy meibomian glands appear like little clusters of bulbs lining a central channel that leads to the eyelid margin and secretes onto the surface of the eye, just behind the rows of eyelashes.
Each row of eyelashes is accompanied by two additional types of glands that function to support the health of the eyelashes. These are the known as the glands of Zeis, which are sebaceous glands, and the glands of Moll, which are modified sweat glands. Both of these are found at the base of each eyelash follicle and serve to keep the lashes from becoming brittle and unhealthy.
Chalazion vs Stye
Chalazia (plural of chalazion) and styes are among the most common eyelid bumps and lumps you’re likely to encounter in your lifetime. Fortunately, both are considered benign and non-cancerous, though can cause some distress if large or sore. It’s quite common for many people to use the umbrella term of “stye” to refer to all eyelid bumps, including chalazia, however these two lesions arise from different underlying causes. Both appear as a swollen lump on the eyelid, and both can feel red, warm, and tender. So, what is the difference between a chalazion vs a stye?
A chalazion is a non-infectious blockage of a meibomian gland, while a stye, also known as a hordeolum, is an infection of either a gland of Zeis or Moll (in the case of an external hordeolum), or of a meibomian gland (an internal hordeolum).
Chalazia may initially begin as an internal stye, which then resolves after a few days into an obstructed meibomian gland with no active infection. A chalazion may present as a general swelling of the eyelid, eventually reducing to a discrete hard bump on the eyelid. The composition of this bump under the skin consists of blocked meibum accumulating in the surrounding soft tissues due to the obstruction of its usual drainage channels. Usually this bump is not painful, even to the touch, and many people are bothered only by the appearance of it more than anything else. In some cases, the chalazion may be large enough to press on the cornea, the transparent front surface of the eye; this can cause some mild distortion of the cornea and temporarily blur the vision. Chalazia can take weeks, and occasionally months, to fully resolve as the body clears away the waste material from the eyelid.
Conversely, a stye is often painful and red as it’s the product of an active infection. External styes are the most common type of hordeolum and appear as a yellowish or white pimple around the base of an eyelash, while an internal stye resembles more a chalazion and presents as a bump further into the eyelid. Styes most often involve a staphylococcal bacterial infection. In most cases, an external stye will rupture on its own within a few days, excreting a small amount of pus and self-resolving.
In the majority of cases, both chalazia and styes will self-resolve without any intervention from an oculoplastic surgery specialist. Your optometrist or GP may recommend applying a warm compress to the eyelid a few times a day to speed up the healing process, but you should never attempt to squeeze or pop either a chalazion or stye, as tempting as it may be! Topical antibiotic ointment may be used for an external stye, but are ineffective for chalazion as there is no active infection to treat.
For severe chalazia or styes that are too slow to resolve with conservative therapy, you may be referred to an eye specialist experienced in oculoplastic surgery. For persistent chalazion, the ophthalmologist may perform a procedure known as an incision and curettage, or may administer a steroid injection into the eyelid. In the case of external styes, the ophthalmologist may pluck out the eyelash associated with the infected gland, or may use a surgical blade under local anaesthesia to assist drainage of infected material from the gland.
Chalazion and styes can often recur, especially if you have underlying factors that make you more prone, such as acne rosacea or meibomian gland dysfunction. Frequently recurrent eyelid bumps, especially bumps that tend to occur in the same location on the eyelid, may require biopsy by an oculoplastic surgery specialist to rule out any other causes, such as an eyelid carcinoma.
Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.