The Avengers are an all-powerful team of superheroes with unique abilities, backstories, and individual and shared histories. But despite repeatedly saving multiple worlds throughout the galaxy, they rarely seek medical attention … perhaps to their detriment.

As dermatologists, we have particular knowledge of readily visible medical conditions. With The Avengers: Endgame now in theaters, we weigh in on what the Avengers should be worried about most.

Thor

Chris Hemsworth as Thor in "Avengers: Endgame."
Marvel Studios / MCT
Chris Hemsworth as Thor in "Avengers: Endgame."

Risky behaviors: slams hammer repeatedly, frequent contact with lightning.

Thor may develop repetitive stress injuries and calluses from his hammer slamming. As for his lightning exposure, he may develop a fernlike branching skin rash called Lichtenberg figures.

Hulk/Bruce Banner

Mark Ruffalo as Hulk.
Mark Ruffalo as Hulk.

Risky behavior: exposure to gamma radiation.

Current signs of disease: green skin, dissociative identity disorder (previously known as multiple personality disorder).

Radiation can have many affects on the body; in the skin especially, it can cause radiation dermatitis and increase the risk of skin cancers.

The Hulk’s green skin can be caused by extensive green tattoos and medication-related discoloration. Patients with chromhidrosis may develop green sweat. The bacteria Pseudomonas is known for causing green nails. Leukemia spreading into the skin can also sometimes appear green (with lesions called chloromas).

Gamora also has green skin, so these must all be considerations for her health as well.

Loki

Tom Hiddleston as Loki.
Disney / Marvel Studios
Tom Hiddleston as Loki.

Risky behavior: various mischief.

Current sign of disease: blue skin.

Blue skin is reported from various medication exposures: the antibiotic minocycline (blue discoloration of the skin), the arrhythmia medication amiodarone (gray skin with bluish tint), and the HIV medication AZT (which can cause blue nails).

The rare blood disorder methemoglobinemia can also cause blue skin; in this disease, an alternative form of hemoglobin predominates in the blood that cannot bind oxygen as well. This disease was responsible for a whole family line in Kentucky (the Fugates) with blue skin. Patients with argyria, a skin condition that can happen if silver builds up in the body, also exhibit blue-tinted skin.

Captain America/Steve Rogers

Chris Evans as Captain America.
Marvel
Chris Evans as Captain America.

Risky behaviors: exposure to experimental serum and suspended animation in cold.

Extended exposure to cold can cause constriction, spasms, or inflammation of blood vessels, in diseases such as Raynaud’s, perniosis (aka chilblains), cryoglobulinemia, and, of course, frostbite.

Cold therapy can be used for cosmetic procedures, such as “cool-sculpting,” to remove fat in some cases. Therapeutic hypothermia protocols are used to improve neurologic outcomes and mortality after cardiac arrest.

Many “experimental serums” may contain anabolic steroids, which can lead to a host of side effects, including acne, testicular shrinkage, and mood alterations – though the Captain doesn’t appear to be suffering from those signs and symptoms.

Black Panther/T’Challa

Chadwick Boseman as Black Panther.
Marvel Studios / MCT
Chadwick Boseman as Black Panther.

Risky behavior: repeated exposure to herbal supplements (heart-shape herb).

The U.S. Food and Drug Administration regulates health supplements, but because they are not considered food or drugs, they do not need any special approval. Often, supplements have later been found to have adverse effects. For instance, biotin, a supplement people take for hair or nail growth, was found to interfere with thyroid function blood tests and caused a delay in diagnosis of a heart attack, leading to death.

Black Panther would be advised to limit his exposure to unregulated and untested active ingredients. It seems there is likely a hallucinogenic component to the heart-shape herb, like peyote.

Iron Man/Tony Stark

Robert Downey Jr. as billionaire industrialist Tony Stark aka Iron Man.
Robert Downey Jr. as billionaire industrialist Tony Stark aka Iron Man.

Risky behaviors: Exposure to metals in the body (including his arc reactor implant, which includes palladium), sexual promiscuity, exposure to novel nanotechnology.

With any metal implant, there can be leakage of iron into the body causing injury. Rashes have been reported from gold (causing a condition called chrysiasis, or an allergic contact dermatitis) and other metals and minerals (silver, zinc, aluminum).

The arc reactor implant in Mr. Stark’s heart could provoke a number of foreign-body immune reactions.

In addition, Mr. Stark’s promiscuity could expose him to sexually transmitted infections. Though he has not reported symptoms, it would be prudent for him to be checked for chlamydia and gonorrhea, as they can be asymptomatic, as well as for syphilis, herpes, and HIV.

Exposure to wearable technology also could be risky, as there are growing reports of allergic skin reactions from wearables causing irritant and allergic contact dermatitis.

Ant-Man/Hank Pym/Scott Lang

Paul Rudd as Scott Lang in Ant-Man.
ZADE ROSENTHAL / Marvel
Paul Rudd as Scott Lang in Ant-Man.

Risky behaviors: rapid changes in size, exposure to insects, threats of (almost) being an insect.

Though Ant-Man is not an actual insect, it’s possible he could carry diseases as a vector, like many insects. For example, mosquitoes and ticks transmit infections ranging from parasites (malaria) to spirochetes (Lyme) and more.

As Ant-Man also rides ants and has giant ants, he could be exposed to the painful stinging and burning of fire ant bites (pustular bite reactions), even with incidental contact.

When people experience rapid change in size (small to large), there is a risk for stretch marks, which typically appear during pregnancy, rapid weight gain, growth spurts, or through the use of bulking agents.

Doctor Strange

Benedict Cumberbatch as Doctor Strange.
Walt Disney Studios Motion Pictures
Benedict Cumberbatch as Doctor Strange.

Risky behaviors: condescending jerk behavior (see also: Iron Man), conjuring of mystic arts and magic.

Unlike the other heroes, Doctor Strange does seek medical attention – and is a doctor. But after his initial devastating injury, he opts to forgo Western medicine and seek alternative/complementary medical treatment for his neurological damage.

We know he has metal rods in his hands, which can occasionally lead to allergic reactions or cause a risk of infection, and we see a glimpse of possible thickened scars along his hands (potentially keloids, though the hands are a rare site for that).

During his training, Doctor Strange is left exposed in the cold peaks of the Himalayas, which could lead to some cold-induced skin injury (see: Captain America).

He also experiences some strange visions after ingesting tea, and if there are psychedelic drugs used in Kamar-Taj, he is at risk for skin reactions from some of those substances (e.g., shiitake mushroom dermatitis is a risk if he had some shiitake mushrooms mixed with “shrooms”).

Captain Marvel/Carol Danvers

Brie Larson as Captain Marvel.
Chuck Zlotnick/Marvel Studios /
Brie Larson as Captain Marvel.

Risky behaviors: exposure to ultraviolet radiation from flying in air and space, Kree blood transfusion.

Airplane pilots are known to have a higher risk of skin cancers (and presumably Kree Starforce members would have an even greater risk). Additionally, exposure to ultraviolet radiation is greater above the Earth’s atmosphere and would require regular application of sunscreen to prevent cancer risk.

Though blood supplies are routinely screened for human infections, blood from a novel species (such as Kree) may carry unique pathogens and thus pose special threats due to lack of immunity.

Groot

Groot is voiced by Vin Diesel.
Courtesy of The Franklin Institute
Groot is voiced by Vin Diesel.

Risky behavior: is a tree.

Though Groot’s exact species of tree has not been clearly defined, he is at risk for many common tree diseases that other Avengers can ignore. For instance, oak wilt kills thousands of oak trees each year. It is a fungus that can move through roots or insects (watch out, Ant-Man) and causes leaf discoloration and death. Other tree diseases with scary names include: apple scab, needle blight, lethal yellow, and thousand canker disease.

Groot should regularly seek a checkup with a botany specialist.

Rocket Raccoon

Rocket Raccoon is voiced by Bradley Cooper.
Marvel Studios 2017
Rocket Raccoon is voiced by Bradley Cooper.

Risky behaviors: is a raccoon.

All raccoons are at risk for rabies, with symptoms of excessive salivation and erratic behavior.

Spider-Man/Peter Parker

Tom Holland as Spider-Man.
Columbia Pictures
Tom Holland as Spider-Man.

Risky behavior: was bitten by a radioactive spider.

Spider bites are extremely rare, and bites from radioactive spiders even rarer. Most bites blamed on spiders are actually from other insects. However, the most dangerous spider bites can potentially cause fatal reactions. For example, a black widow spider bite can cause muscle cramps and abdominal pain. Brown recluse bites can cause severe ulcerlike reactions. Though tarantula bites are generally not of concern, these spiders can defensively release their hairs, which can cause significant eye injuries.

Black Widow/Natasha Romanova

Scarlett Johanssen as The Black Widow.
Marvel
Scarlett Johanssen as The Black Widow.

Risky behavior: spends time with the rest of the Avengers.

Though she appears to have flawless skin, it’s worth noting that the super spy’s hair color has changed. Hair dyes, particularly those containing the chemical paraphenylenediamine, are a frequent source of allergic contact dermatitis (itchy rashes like poison ivy).

Vision

Risky behavior: is a robot.

Although we do not yet know what sort of skin issues artificial life forms may develop, this is likely to be an expanding area of interest as artificial intelligence becomes more commonplace in the near future.

Jules Lipoff, M.D., is assistant professor of dermatology and Misha Rosenbach, M.D., is associate professor of dermatology at the University of Pennsylvania Perelman School of Medicine. Superheroes, Marvel Comic Universe characters, and any mortals in need of care are welcome in their clinics anytime.