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22 Photos That Show What Mast Cell Activation Disorder Looks Like

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Mast cell activation disorder (MCAD) occurs when the body’s mast cells don’t function as they should. Mast cells are part of the immune system and help keep people healthy by protecting against infection and participating in the inflammatory process. They are also involved in allergic reactions and anaphylaxis, and selectively release substances called mediators when an allergic or mast cell reaction occurs.

When someone has a mast cell disorder, these mediators may be activated inappropriately in response to various triggers, and can accumulate in organ tissues. There are two main types of mast cell activation disorders: mastocytosis (an accumulation of mast cells in one or more organ systems) and mast cell activation syndrome (when people experience episodes of mast cell activation without evidence of a proliferative mast cell disorder). MCAS is also occasionally seen as a comorbidity of conditions like Ehlers-Danlos syndrome, postural orthostatic tachycardia syndrome (POTS), and as scientists are starting to investigate, possibly fibromyalgia. Common symptoms of a mast cell reaction include itching, hives, headache, gastrointestinal issues and low blood pressure.

We wanted to better understand how MCAD affects people, so we asked our Mighty community to share a photo that shows what it can look like to live with mast cell activation disorder. Those with the condition may have different triggers and different reactions, but if any of the following experiences look familiar, know you’re not alone.

Here’s what our community shared with us:

1. “Still no idea what the trigger is.” – Melissa L.

red rash across a woman's back

2. “My airways are constricting, where it is getting difficult to breathe, so I am nebulizing cromolyn sodium and keeping an eye on my heart rate and pulse ox (with the help of my lovely cat).” – Jo C.

woman wearing a face mask and sitting with her cat

3. “Constant irritation and random splotches of red. This happened when I walked into a new building and my skin didn’t like something in the air. Mast cell is always unpredictable.” – Heidi W.

red rash on a woman's chest

4. “My most prominent reaction is my ears turn red, and get blindingly hot. It’s painful. It’s a mast cell reaction, and I often get it during a food reaction, or after I’ve encountered an environmental trigger. It’s small, relatively mild, but I would honestly take any other reaction over this. It often lasts for hours, and will spread to my cheeks and down my neck if I’m not super careful.” – Saylor A.

a person's ears that have turned red

5. “I play viola, and sometimes I have a mast cell reaction to the heat that is produced by my hands while I am playing. Heat and exercise allergies are real and thanks to MCAD, I never know when they will happen.” – Christa R.

red rash on a woman's arm

6. “A hot, humid day is all it takes.” – Marie B.M.

woman with red blotches across her cheeks

7. “These are the hives I got from trimming a large bush that was damaged in an ice storm. Some of the branches touched my arm and caused a few immediate hives, and an hour later my forearm exploded in the most itchy rash I’ve ever had. I wanted to rip my skin off!” – Elisa S.

red hives on a woman's arm

8. “I was outside during the summer – didn’t touch anything but still had a full blown allergic reaction.” – Kayla C.

red blotches across a woman's neck and chest

9. “Took a few days to figure out I was allergic to the antacid I was taking for MCAD.” – Rebecca A.

small bumpy rash on a woman's arm

10. “I wore eyeshadow.” – Kristen P.

red rash on a woman's eyelid

11. “My cheeks flushing and radiating heat… I swear you can use them as a fireplace.” – McKenna R.

woman with red flushed cheeks

12. “My thighs getting reddish and a little bumpy out of an ‘allergic’ reaction after trying on a new pair of jeans. The ‘rash’ calmed down right after I removed the jeans from my skin.” – Soja M.

red rash on woman's thighs

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13. “With mast cell I’m allergic to all adhesives and bandages in the hospital. Even after having my defibrillator placement surgery, I went home with blisters all over the front of my chest and rashes from the bandages needed to stop the bleeding.” – Jena J.

large red rash on a woman's shoulder

14. “1. Rash, swelling and flushing caused by sensitivity to sunlight and heat. This was after around 15 minutes outside. 2. Reaction to adhesive wrap after having blood drawn. The wrap was only on until I got home, so around 10 minutes. 3. Painful raised and itchy hives. Unknown cause, but lots of inflammation along with it. 4. Full body rash/flushing after a shower. Sometimes I react to my shampoo/soap etc, and other times I don’t. This was one of the times I did. 5. Reaction to electrodes that I wore for cardiovascular testing. Sometimes I react, sometimes I don’t. This is a mild reaction.” – Christina G.

collage of photos of woman experiencing red rashes

15. “Twenty minutes after dinner when I forgot to take a Benadryl before eating.” – Robin T.

close up of woman's eyes that are red, swollen and watery

16. “I wore a dress from the store without washing it first. The doctor said it is probably a reaction to formaldehyde resin.” – Kristen P.

rash of small red dots across a woman's arms and chest

17. “I am allergic to adhesives. These were raised rashes from the medical tape and Dermabond used during my cholecystectomy. You can also see the rash where a large Bandaid was placed in the center of my abdomen.” – Ashley B.

red rashes and scars across a woman's abdomen

18. “Fragrances, chemical smells and some pollens make my sinuses and eyes puffy and painful and sounds hurt my ears and I get a migraine. If the reaction is bad or if I have too many reactions within days of each other my tongue and throat swell up and I need an injection.” – Louise M.B.

selfie of woman wearing glasses and headphones with flushed cheeks

19. “The pressure of wearing a sock caused my skin to swell and hives to appear. Despite soothing creams, anesthetic gels, ice and the quadruple dose of antihistamines prescribed by an immunologist, it got so itchy that I subconsciously rubbed my heel on my itchy foot until I burnt the skin off. Even after that, the swelling and itchiness was still a worse problem than the burn (which took months to heal to a scar).” – Alexandria P.

rashes and burns on a woman's leg

20. “I have tons of reactions from environmental things to chemicals to natural things. I have skin involvement daily like for example brushing my teeth today caused hives in my mouth. Here’s a pic where it caused me to get a horrible lung infection that lasted almost a month that required oxygen, steroids and neb treatments. Mast cell activation syndrome for me is my lungs, stomach and skin involvement. I have symptoms daily but haven’t had anything life-threatening in a while besides this chest infection. I’m really grateful for such a great boyfriend to take care of me.” – Kitty M.

woman lying in a hospital bed with her boyfriend standing next to her

21. “Someone wore strong perfume at the office.” – Kristen P.

red rashes on a woman's arms

22. “I tried a new moisturizer.” – Rebecca K.I.

woman with a red rash across her chest

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