A new case report published in Annals of Clinical and Medical Case Reports describes a 37-year-old woman who developed severe, painful swelling after she received hyaluronic acid lip fillers — a reaction doctors eventually realized was due to mast cell activationMast cell activation Describes when mast cells release histamine and other mediators into the blood stream in response to an allergen or other trigger. This leads to symptoms like fatigue, rash and, in severe cases, anaphylaxis., and that lead to a systemic mastocytosis (SM) diagnosis.
The case shows that there can be more than meets the eye when reactions occur. The authors suggested that severe, prolonged swelling after a filler injection shouldn’t be written off as a normal complication, especially when a patient also has skin symptoms linked to mast cellMast cell A type of white blood cell produced in the bone marrow. They help defend against infections and play a key role in allergic reactions. In SM, mast cells become overactive and build up throughout the body. disorders, as this patient did.
The authors reported that the woman had experienced recurrent hives for around a month. She also had multiple reddish-brown spots and small bumps, mainly on her torso and arms. When the affected skin was rubbed, the spots became red and swollen, a reaction known as Darier’s sign that is common in people with mast cell disorders.
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The woman received lip augmentation with 1 mL of hyaluronic acid filler, and didn’t initially have any complications. Approximately 24 hours after the procedure, however, she experienced progressive and painful swelling around her mouth. Small, grainy bumps and nodules also appeared on the inner surface of her lips. These symptoms lasted for more than 48 hours.
Clinicians treated the reaction with oral prednisone (a steroid), first at 40 mg daily for five days followed by 20 mg daily for three days, alongside an antihistamine. Her symptoms progressively improved and completely cleared.
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Doctors took a biopsy of the affected skin and mucosa which revealed an infiltrate containing lymphocytes and mast cells. Laboratory testing showed expression of CD117, a marker of mast cells, and aberrant CD25 expression, which can help identify abnormal mast cell populations.
Based on the clinical findings and tissue analysis, the authors diagnosed her with SM.
The authors noted that although they are generally considered safe, hyaluronic acid fillers may trigger mast cell activation in people with an underlying mast cell disorder. They suggested that the physical force of the injection and the tissue’s response to the filler may have triggered the woman’s symptoms.
“This case underscores the importance of viewing disproportionate post-filler edema not merely as a technical complication, but also as a possible ‘revealing event’ indicating an underlying systemic disease and warranting thorough investigation,” the authors concluded.
