What is the Differential Diagnosis of Normal Eye Crusts or Rheum?

Patient Presentation
A 6-month-old male came to clinic for his health supervision visit. The parents had several questions about feeding and development, and were particularly concerned because for the past few days he had more eye sleepers in the morning. His mother said that “his eye was almost shut one morning.” They used a warm washcloth to clean it but it returned after naps as well. “Sometimes his eye is red too,” his father said and with more questioning noted that it was the inner canthus that was mildly red and which resolved after cleaning. The discharge was dark yellow and did not reaccumulate while awake. The patient was not bothered by it. A picture on the parents’ phone showed a mild amount of yellowish thin crust in the bilateral canthi without redness of the skin. The past medical history was unremarkable.

The pertinent physical exam revealed growth parameters in the 10-25% with normal vital signs. He was happy and playful. His eye examination showed normal structures without any irritation of the skin, lid margins and no redness of internal structures. No discharge was noted.

The diagnosis of normal eye crusts or rheum was made. The parents were instructed on normal eye hygiene.

Discussion
Sleep crusts go by lots of names including “sleepies,” “sleepers,” “eye goop,” “eye sand,” and many other names. Rheum is the medical term. Sleep crusts are common. The sandman from folklore, is said to sprinkle magical sand into people’s eyes to encourage sleep and wonderful dreams.

Crusts are composed of mucous, oil, skin cells, and dust/debris that is all a normal part of normal tear production and protection of the eye. While awake, blinking helps to clear this from the eye and move it to the nasolacrimal duct. This does not occur during sleep and therefore there can be overflow into the corners of eye or along the lashes.

Normal crusts may be:

  • Lighter yellow, white or clear in color
  • Thick or thin in consistency
  • May or may not stick the eyes together. If sticking together it should be easily removed and not recurring especially while awake.
  • Generally should not be causing redness of the skin or lids. It can cause minor skin irritation but after removal should improve relatively quickly and not recur.
  • Occur while asleep, not while awake

    Normal crusts should not:

  • Cause redness of the globe or other internal eye structures
  • Be painful or gritty
  • Cause blurred vision or sensitivity to light
  • Be reaccumulating quickly
  • Have thick, globs of discharge that are “floating” across the eye

    If eye crusts are the only symptom and easily removed and without reaccumulation, then this is usually normal.

    Parents are usually most concerned because of the risk of easily transmissible infectious conjunctivitis, and this can be difficult to differentiate from normal or other causes.
    Parents may have difficulty describing the rheum. Yellow may be described as green because of the lighting for example, and dark vs light yellow also can be difficult to discern.
    Parents often are also concerned that the lashes were stuck together, but this can be normal if it is easily cleaned and not reaccumulating.
    Parents will also report that the eyes are red, when they mean that the lids or other skin structures are reddened. Red skin can be a sign of infection but can also be minor irritation from the rheum that should resolve relatively quickly after cleaning.

    Patients should be reminded for cleaning eyes to:

    • Use washed hands before cleaning eyes
    • Use clean washcloths and towels
    • Warm water washcloths and mild gentle rubbing should break up the crust
    • Remove contact lenses before sleep
    • Clean all makeup before sleeping

    Learning Point

    The differential diagnosis of eye crusts includes:

    • Blocked tear duct – Common in newborns and young infants. May also have concomitant infectious conjunctivitis.
    • Conjunctivitis, infectious
      • May be difficult to tell which type and can have more than 1 type concurrently. Bacterial and viral are highly contagious.
      • Allergic – usually bilateral, thin and watery. May have pruritis
      • Bacterial – unilateral or bilateral, with thick discharge that reaccumulates quickly
      • Viral – usually bilateral, thinner discharge
    • Keratitis
    • Blepharitis
      • Infectious including parasitic
      • Atopic dermatitis
      • Seborrhea
    • Chalazion/Hordeolum/Stye – A review can be found here
    • Demicosis
    • Dry eye

    Questions for Further Discussion
    1. What causes red eyes? A review can be found here
    2. How do you treat chalazion/hordeolum/styes?
    3. What are indications for consulting ophthalmology?

    Related Cases

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

    Information prescriptions for patients can be found at MedlinePlus for these topics: Eye Diseases and Eye Infections.

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Ouedraogo M, Ventejou S, Leducq S, Desoubeaux G, Maruani A. Crusts on the Eyelashes. J Pediatr. 2019;209:254-254.e1. doi:10.1016/j.jpeds.2019.02.002

    Gurnani B, Badri T, Hafsi W. Phthiriasis Palpebrarum. In: StatPearls. StatPearls Publishing; 2023. Accessed October 30, 2023. http://www.ncbi.nlm.nih.gov/books/NBK459226/

    What Is Sleep Crust? American Academy of Ophthalmology. Published March 29, 2021. Accessed October 17, 2023. https://www.aao.org/eye-health/diseases/what-is-sleep-crust

    Why might someone have crusty eyes in the morning? Accessed October 30, 2023. https://www.medicalnewstoday.com/articles/crusty-eyes-in-the-morning

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa