Kratom, or Mitragyna speciosa, is a plant originating from Southeast Asia. In recent years, kratom has gained popularity due to its ability to induce stimulant-like effects at low doses and opioid-like effects at high doses.¹ Kratom leaves may be boiled into a tea, chewed, smoked, or dried, powdered, and/or put into capsules for consumption. Often the herb is used for pain relief following opioid withdrawal, but many use it for its psychoactive effects as well.² While kratom possesses analgesic properties, it is not regulated by the FDA, and can have a variety of dangerous side effects. Side effects of kratom include tachycardia, drowsiness, vomiting, confusion, hallucinations, respiratory depression, and cardiac arrest.³ Kratom also possesses the potential for addiction and dependency due to its opioid-like properties.⁴ This case study details an additional side effect of discoloration of the skin in sun-exposed areas when taking kratom in high doses.

A 30-year-old Caucasian male with no prior medical history or long-term medication use presented with a dark gray-blue discoloration of the skin. The hyperpigmentation is present in the cheeks of the face, the back of the neck, and the backs of the hands and forearms.

The patient reported taking kratom for five years. This started due to an opioid addiction following a high school injury for which he received opioid pain medications. He developed an opioid use disorder, and eventually decided to replace his pain medications with kratom to ease his pain. The patient reported taking capsules of the herb and would sometimes put the powder directly on his tongue and wash it down with fluids. He took high doses to achieve an opioid-like effect, starting at 8-15 grams a day for the first year. At this dose, he noticed problems with his vision and developed anxiety. For the next 4 years he continued to take 3-7 grams a day. He says he did not see an ophthalmologist for the vision changes, and that once he lowered the dosage, he no longer had any problems with vision. He has not had any issues with vision since then. He did not notice any discoloration of the skin until he was 4.5 years into using kratom. He described a sudden onset and fast progression of darkening in photo-distributed areas (Figure 1). There was no hyperpigmentation on the nails or on any mucosal areas, including the oral cavity. Additionally, there were no pigmentation differences in the sclerae or irises of the eyes. The patient noted that he goes fishing often and was regularly exposed to the sun.

He did not have any other medical conditions and did not take any medications or supplements that cause hyperpigmentation while using kratom. He has not taken minocycline before or any other chronic medications. The patient stopped using kratom in May 2022, but the discoloration remains. It has not regressed in the following 16 months after discontinuing kratom use.

Figure 1.