Fennel has been used traditionally to treat a cough, bronchitis, stomach discomfort, flatulence and sinus congestion. The herbal supplement has not been evaluated by the FDA for its effectiveness and should only be used under a doctor's supervision. If you develop a rash and hives after taking a fennel supplement, you should discontinue use and call your doctor. You could be experiencing an allergic reaction, which could lead to anaphylaxis, a severe allergic condition.
Fennel Allergy
Symptoms of a fennel allergy may not develop the first time you take the supplement. If your immune system identifies the substance as harmful, it will slowly build up a resistance by creating specific immunoglobulin E, or IgE, antibodies to fight off the nettle. Once your immune system creates enough IgE antibodies, you will then experience an allergic reaction. Histamine is produced in soft tissue throughout the body and commonly affects the skin causing skin rashes and hives.
Hives
Hives is a skin reaction that can appear anywhere on the body in any shape or size. The rash forms in clusters of red, raised, itchy welts that begin from small spots that grow into large blotches. Hives do not typically cause any long-term damage, but it is alarming if they develop in the throat, nose or ears. Hives can begin in one area of the body and migrate to another area without any cause. Scratching the rash will make it worse, causing it to spread and increasing its itchiness and pain.
Other Rashes
Eczema is another common allergic skin reaction from taking fennel. It is a chronic condition that can be triggered by certain medications, herbs and foods. Eczema typically forms on the face, the arms and legs, but it can develop anywhere. The rash appears in blisters or patches of dry and scaly skin. You may develop a general itch and inflammation as a result of an allergic reaction to the supplement.
Treatment
Treating hives and a skin rash from fennel begins with a clinical diagnosis. Your doctor may recommend allergy tests to determine the cause of the reaction. Once identified, your physician will recommend avoiding the consumption of nettle. Hives and other rashes can be treated with oral and topical antihistamines. You can also use hydrocortisone or other steroid-based lotions to reduce swelling and itchiness, under your doctor's direction.
