Ascent to Altitude: A Benign Cause of Splinter Hemorrhages


  • Daniel M. Musher MD

    Corresponding author
    1. Departments of Medicine, Baylor College of Medicine, Houston, TX, USA
    • Medical Care Line, Infectious Disease Section, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, USA
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Corresponding Author: Daniel M. Musher MD, Chief, Infectious Disease Section Veterans Affairs Medical Center, Houston. TX, USA. E-mail:


Splinter hemorrhages appear in a variety of conditions. One identified cause is ascent to altitude, but trauma and extreme conditions have been thought to be responsible. We document the appearance of splinter hemorrhages in a group of adults during several days of easy touring at an altitude of 11,000 feet (3,350 m).

Splinter hemorrhages are seen in conditions of varying severity including (but not limited to) infective endocarditis, vasculitis, the antiphospholipid syndrome, chronic meningococcemia, ingestion of tyrosine kinase inhibitors, trauma,[1] and activities of daily living (especially in the elderly).[1, 2] Chronic[4] or acute[5, 6] exposure to high altitude has also been associated with this finding, but, in this scenario, extreme conditions and trauma have been thought to play a causative role. This report describes splinter hemorrhages associated solely with ascent to moderately high altitude and in the absence of associated trauma or extreme conditions.

Case Report

This 71-year-old physician presented for evaluation of numerous splinter hemorrhages (Figure 1). He denied fever, chills, muscle or joint pains, chest pain, difficulty breathing, or neurologic symptoms. He had no known heart murmur, and was in general good health, with hypertension, well controlled on hydrochlorthiazide and atenolol, and diabetes, well controlled on metformin 500 mg daily (hemoglobin A1c = 5.6). He had just returned from a 7-day trip to Peru where he spent 2 days in Cuzco (altitude 11,000 feet) and 1 day in Machu Picchu (altitude 8,000 feet). He took acetazolamide 500 mg twice daily beginning 2–3 days before leaving for his trip. He felt well and had no subjective fever. Physical examination revealed no other petechial lesions in the conjunctivae or skin. There was no new heart murmur. Neurological screening examination was normal. No treatment was given. Occasional new splinter hemorrhages continued to appear in the ensuing 90 days.

Figure 1.

Subungual splinter hemorrhages can be seen under each of three fingernails in the index case observed in this mini-outbreak of splinter hemorrhages.

The patient was one of a group of eight adults (aged 42–81 y) who traveled together. All were in generally excellent health, and all took acetazolamide 500 mg twice daily beginning 2–3 days before arrival. For 1–2 days they toured in and around Cuzco, either walking without backpacks or taking vans. They then took a leisurely 3-hour train ride to Machu Picchu where they hiked the ruins, either with no backpack or with a light pack (weight <10 pounds). Examination of the other seven subjects 1–3 days after descent from altitude revealed that four had splinter hemorrhages. Thus, in total, five of eight persons who hiked ruins at Maccu Picchu had splinter hemorrhages (range 1–8 hemorrhages per hiker, median 1). Of the five who had splinter hemorrhages, three were taking 60 mg aspirin daily or three times weekly compared to one of the three who did not have hemorrhages. Only one of the subjects had symptoms (headaches) that she attributed to altitude sickness.


Rennie,[5] a physician and mountain climber, described an association between ascent to altitude and splinter hemorrhages. While hiking in the Himalayas, he noted that hemorrhages appeared in his nail beds at 19,300 feet, after he carried a 60-pound backpack through the snow for 4 h. In his expedition, 7 of 15 fellow climbers had 1–19 subungual hemorrhages. Several of his proposed causes—trauma, extreme exertion, cold exposure, and/or impeded venous return by rucksack straps—have been generally accepted,[4, 6, 7] but they clearly do not apply to the situation described herein.

Decreased barometric pressure and hypoxemia appear to be the likely common features contributing to the appearance of these hemorrhages. Although Rennie dismissed capillary fragility as a possible explanation, Hunter et al.[8] used petechiometry to show that capillary fragility increases in proportion to altitude. Since these investigators did not provide supplementary oxygen to any of their subjects, their method could not distinguish between low barometric pressure and low oxygen content of air. Low barometric pressure is likely, however, to be the principal cause, since the examination of hypoxemic patients in medical intensive care units does not regularly reveal splinter hemorrhages. Interestingly, retinal hemorrhages (Roth spots) have also been documented in mountain climbers at very high altitudes,[9] supporting the hypothesized role for capillary fragility.

The present report describes the appearance of splinter hemorrhages in five of eight healthy adults who spent 2–3 leisurely days touring at an altitude of 8,000–11,000 feet. All of the subjects were taking acetazolamide; only one had symptoms consistent with altitude sickness. These observations indicate that ascent to altitude, unassociated with extreme conditions, trauma or symptoms of oxygen deprivation, needs to be regarded as a benign cause of splinter hemorrhages.

Declaration of Interests

The author states he has no conflicts of interest to declare.