Yugan, or how to end your Central Asian mountain vacation burning in phototoxic hell

This article applies to all of Central Asia, but I’ll use Tajikistan as an example. Many tourists dress inappropriately in rural Tajikistan. They start in Kazakhstan, Kyrgyzstan or they first visit cities in Uzbekistan or arrive via the Pamir Highway, and in these locations wearing shorts or having bare shoulders is not really a problem for the locals. And over the last decade I’ve seen shorts become far more common in cities like Dushanbe. But many rural areas maintain their dislike for hairy, bare legs sitting on their guesthouse kurpachas. Kuhistoni Mastchoh is not Almaty.

I'll admit that I occasionally wear shorts in hot weather, but I wear long, over-the-knee shorts and I put on pants when I come to a village (I have convertible trekking pants/shorts that zip on and off quickly). But some tourists and expats just don't care, and they feel that wearing the shortest short-shorts anywhere and everywhere is their right as a privileged foreign guest.

OK, fine. Go to the mountains of Tajikistan (or anywhere in Central Asia) wearing shorts. Bare your arms, bare your legs, bare your shoulders. You will regret it. There is an attacker waiting for you throughout the mountains of Central Asia. In every country. Nature here has created a punishment for those who dress inappropriately: severe phototoxic burns. Not a sunburn, but a sun-assisted chemical burn that will quickly blister and leave you in pain for days, in itchy torment for quite a while after that, and possibly even leave you with black scars on your skin for up to six months.

Bare legs, meet your nemesis - Prangos pabularia, known locally as "yughan," (Tajik pronunciation) or "yugan" (Russian pronunciation). Photo below via CABCN.

It seems simple enough to just avoid yellow flowering plants, like these obvious ones below:

But yugan doesn’t have flowers until its mature phase. Here is younger yugan below (the dog’s fur below and the horse’s coat above offer protection - except for the bare skin around the eyes and near the ears):

Long scientific name: Prangos pabularia Lindley; Russian names: Прангос кормовой, Прангос гиссарский, and Прангос зеравшанский.

Yugan (Yughan, or Юған in Tajik): is a pretty green plant at mid-elevations that looks like oversized dill. Yugan is a member of the Apiaceae (or Umbelliferae) family, and it is phototoxic. The sap of the plant combines with the sun to give your skin a chemical burn (phytophotodermatitis). It will sting badly, and the pain and blisters will last for days. Black hyperpigmentation scars then remain on the skin for about 6 months or longer. This is only a problem at mid-elevations at the beginning of the summer (April/May/June/July) until the plant dries out and becomes harmless. However, some areas with moist ground (next to a stream or in a gully), at a higher elevation or in a shady area may have green yugan longer into the season.

If you want to familiarize yourself with how yugan looks, then check out the photos at these links: Prangos pabularia photo gallery, Prangos pabularia in Uzbekistan, Prangos pabularia in Kazakhstan. If you want the botany taxonomic information, start here, and if you want to read about its folk medicine uses, check out this article.

Avoiding Yugan

Avoid problems by not wandering into the high grass and vegetation or bushes, and by wearing long pants.

But...it's not just about wearing long pants. Any skin that touches the plant or touches something that touched the plant can get burned (the plants sap can transfer from your trekking poles, boots, backpack, etc. to your skin).

So, if you are traveling through thick greenery, you should cover not just your legs, but also your arms and hands. Yes, your hands. There is a good example below provided by a Russian climbing team that started in the upper Vanj Valley. One of their members hiked through the tall green plants without gloves. You can see the result on his hands (Yudin/Meshkov 2010 expedition, via Mountain.ru):

The poor guy then had to spend the next 10 days on glaciers, peaks and high passes with his hands burning. Look at those blisters, and then imagine them covering your arms and legs as well.

I've heard other stories, mostly just mild burns on bare legs or arms, but some are anecdotes of severe pain and scarring. One Russian climbing group (Purikov, 2010) that started in the Romit gorge reported that the burns on their legs turned black and remained as black scars for months:

In the tall grassy thickets, unexpected trouble awaits us. Among the innocent meadowsweet and horse sorrel hides a terrible hogweed, or yugan. Almost the entire group, to a greater or lesser extent, got into it with various parts of the body (many wore shorts and T-shirts). The blisters formed in 2-3 days, and disappeared only by the end of the hike. The dark burn marks remained for several months. We recommend the following groups: wear long sleeves, long trousers in the lower reaches, adhere to traditional paths..

I checked their photos, and sure enough, you can see the yugan (the two plants on the bottom left):

Where can you find this plant? From Turkey to the Himalayas, and as far north as Kazakhstan. in Tajikistan it is found anywhere between 800 and 3500 meters, minus the far eastern mountain desert areas. Yugan’s range is show below in black, via the free e-book Illustrated flora of Tajikistan and adjacent areas.

So, how to avoid this terrible plant?

If it's later in the season and the greenery has turned to a dry golden-brown, then you have little to worry about. The yugan is now harmless. And some trails are clear of plants and go through wide open areas where you are safe. But a side trip to a shady/moist area to fill up a water bottle or find a toilet may lead you to brush up against this plant.

My defensive approach is as much about avoiding sunburn as it is about avoided phototoxic burns from yugan. Yugan can't burn you without the combined effect of the sun and the phototoxic chemicals from the plant (if you only travelled at night, the yugan could not hurt you). So on longer treks or when exploring unfamiliar areas off-trail, I wear long pants, long sleeve shirt and light, breathable gloves. This saves me from worrying about regular sunburn (and carrying a big bottle of sunblock cream everywhere), and from worrying about yugan. Of course, I also do shorter day hikes in short sleeves (with sunblock and not in places where/when yugan might be growing).

"But then I will be too hot!" No, you won't. Not if you wear the appropriate clothing. Google "sun shirt," "sun hoodie," "sun gloves," and "neck gaiter." These are very breathable lightweight clothing options with - ideally - UPF 50 skin protection. Match this with breathable trekking pants and you will be both protected from the sun, protected from yugan, and not too hot. Budget option: any lightweight, long-sleeve shirt, a light scarf for your neck and whatever lightweight gloves you can find.

So, for those of you that have spent time trekking in this region, why haven't some of you heard more about this plant? Even just from second-hand information? My best guess is that many people mistake it for regular sunburn. As for Tajikistan, the two most popular trekking regions (Fann and Pamirs) in Tajikistan don’t see green yugan during the height of the trekking season.

The worst story I heard? A guy frolicked in the yugan wearing shorts and a t-shirt on a sunny day, admiring the pretty flowers. He then spent the next week in pain, unable to lie down comfortably or sleep more than a few hour per night due to the pain. But usually the stories are far less severe.

Anything else you should know about yugan? Well, when it's dried out (like the sample above) it is not just harmless, but edible for livestock and used for fodder. It also has folk medicine uses for the roots and the small fruits. Among its alleged uses is as a diuretic, a sedative, an aphrodisiac, a balm for scabies and gum disease, and as an abortion pill. Not exactly something that would be useful to the average trekker or hiker.

Do you really need to worry? Not if you take the basic precautions of covering your skin. I’ve been visiting Tajikistan and Kyrgyzstan’s mountains since 2009 and I haven’t yet been burned by yugan, but I was warned ahead of time and took the needed precautions.

Now you just have to worry about the scary sheep dogs, hypothermia, and other dangers of the mountains.