Cortisone injections are a common medical procedure, often used to deliver anti-inflammatory medication directly to a painful or inflamed area, such as a joint or tendon. While highly effective for localized symptoms, these injections can sometimes lead to a temporary and often startling side effect known as facial flushing. This reaction, characterized by a sudden onset of warmth and redness across the face, is a systemic response to the medication. It is important to understand that this flushing is typically a benign, self-limiting side effect and not an indication of a severe allergic reaction.
The Vasoactive Mechanism of Corticosteroids
The core reason for facial redness after a cortisone shot lies in the drug’s effect on blood vessel function. Corticosteroids, the medication used in these injections, have a vasoactive mechanism, meaning they influence the tone and diameter of blood vessels. The flushing itself is the direct result of temporary vasodilation, which is the widening of small blood vessels beneath the skin’s surface, particularly in the face and neck area.
This vasodilation increases blood flow to the skin, creating the sensation of warmth and visible reddening. The steroid, once in the bloodstream, interferes with the body’s normal vascular regulation. This interference may cause a temporary reduction in sympathetic nerve activity, which normally maintains a constricting tone on blood vessels. Relaxing this natural vasoconstriction allows facial blood vessels to dilate, leading to the flushed appearance.
Systemic Absorption and Flushing Timeline
Facial flushing occurs despite the injection being given locally, such as into a knee joint or an inflamed bursa. This happens because the steroid medication is gradually absorbed from the injection site into the general circulation (systemic absorption). The drug must first leave the localized area of the injection before it can travel through the bloodstream to affect the distant blood vessels in the face.
The onset of flushing aligns with the time it takes for the drug to reach a sufficient concentration in the body’s circulation. Typically, the reaction does not start immediately but begins hours after the procedure, commonly within the first 24 hours. The flushing frequently peaks during the first one or two days post-injection, as the systemic concentration of the corticosteroid reaches its maximum level.
Expected Duration and Symptom Relief
The facial flushing following a cortisone injection is a temporary side effect that usually resolves quickly on its own. For most people who experience it, the warmth and redness will subside completely within one to three days. While the experience can be uncomfortable, the reaction is not considered medically dangerous and does not require formal medical treatment.
To manage the temporary discomfort, one can apply a cool, damp cloth or compress to the flushed areas of the face. It is also helpful to temporarily avoid known flushing triggers, such as hot beverages, spicy foods, alcohol, or strenuous exercise, until the symptoms pass. It is important to contact a healthcare provider immediately if the flushing is accompanied by more severe symptoms, such as difficulty breathing, hives, or swelling of the lips, tongue, or throat, as these could indicate a rare, true allergic reaction.