Ceruminous Glands

1. Overview

Ceruminous glands are specialized modified apocrine sweat glands found exclusively in the external auditory canal. They are responsible for producing cerumen, commonly known as earwax—a substance that plays a protective and lubricating role in the ear. Although their primary function is local, ceruminous glands are considered part of the integumentary system because they are derived from the epidermis and contribute to skin-related defense mechanisms.

2. Location

Ceruminous glands are located in the cartilaginous portion of the external auditory canal, specifically in the outer one-third of the ear canal. They are embedded within the skin and open into the hair follicles or directly onto the skin surface of the canal. These glands are not found in the bony part of the canal, which is lined by thinner skin lacking adnexal structures.

3. Structure

Ceruminous glands share structural characteristics with apocrine glands but exhibit certain modifications:

• Tubular, coiled glands located deep within the dermis and subcutaneous tissue.

• Secretory portion is composed of columnar epithelial cells surrounded by contractile myoepithelial cells.

• Ducts are short and open into adjacent hair follicles or directly onto the canal surface.

These glands often work in conjunction with sebaceous glands, and their combined secretions form cerumen.

4. Function

Ceruminous glands are primarily responsible for:

• Production of cerumen (earwax), which consists of a mix of ceruminous and sebaceous secretions, along with shed skin cells.

• Moisturization of the ear canal to prevent drying and cracking of the skin lining the auditory canal.

• Trapping of dust and debris to prevent particles and insects from reaching the tympanic membrane (eardrum).

5. Physiological role(s)

Ceruminous glands play important roles in maintaining ear health:

• Antimicrobial defense: Cerumen has acidic pH and contains lysozymes and other substances that inhibit the growth of bacteria and fungi.

• Barrier protection: Acts as a physical and chemical barrier against foreign bodies and environmental contaminants.

• Self-cleaning mechanism: The movement of the jaw during talking or chewing helps transport cerumen and trapped debris outward, cleaning the ear canal naturally.

6. Clinical Significance

Although small and localized, ceruminous glands can be involved in several clinical conditions:

• Impacted cerumen:

  • Occurs when earwax accumulates excessively and hardens, blocking the ear canal.

  • Can cause hearing loss, discomfort, tinnitus, and even infection.

  • Treated with cerumenolytics, irrigation, or manual removal.

• Otitis externa (swimmer’s ear):

  • Bacterial or fungal infection of the external auditory canal, sometimes related to disruption of the protective cerumen barrier.

• Ceruminous gland tumors:

  • Rare; include benign adenomas and malignant carcinomas.

  • May present as a mass in the external ear canal, causing pain, hearing loss, or otorrhea (discharge).

  • Treatment usually involves surgical excision.

• Dry ear canal:

  • In older adults or after aggressive cleaning, reduced cerumen can lead to itching, irritation, and increased infection risk.

• Dermatitis of the ear canal:

  • Inflammation or hypersensitivity reactions can affect ceruminous gland function or cerumen composition.