The hypersensitivity reaction of the immune system is the onset of allergy. Usually, the immune system gets activated due to any microbial attack, i.e. invasion of a foreign body. However, some of us are very much sensitive to the exposure of certain elements such as dust mites, molds, pollen, insect stings, food and certain medicines.
This acts as a false alarm which triggers immune system and activates mast cells. This further releases histamine and causes hypersensitivity reactions. In most of the cases, the outcome of the hypersensitivity reaction instigates inflammatory condition. Both, genetic and environmental factors play a crucial role to start allergies.  The currently available therapeutic management to control allergies include anti-histaminic medications and anti-inflammatory drugs. 
The huge burden of side effects associated with synthetic drugs for chronic conditions, impels the health conscious people to choose medicines originated from natural sources which have negligible side effects.
Black seed oil is one of the evidence-based search results, which can efficiently manage allergic reactions with negligible adverse events.
Why is black seed oil better option to treat allergies?
The most common anti-allergic medications are categorized as antihistamines, corticosteroids, and mast cell stabilizers.
• Antihistamines block histamine release and stop an allergic reaction, but synthetic medications those fall under antihistamines often causes drowsiness and fatigue.
• Corticosteroids act as an anti-inflammatory agent in allergic reaction; but long-term systemic administration often causes osteoporosis, stomach ulcers, muscle weakness, cataracts, increased blood glucose level and growth retardation in children. The oral administration often increases the risk of hypertension-related complications. In some cases, even the local application causes skin irritation.
• Mast cell stabilizers stabilize mast cells and prevent hypersensitivity reaction of the immune system. This category drugs provide delayed action. 
Therefore, it is well established that application of synthetic anti-allergic drugs has several undesirable side effects.
There are several research studies that showed that the black seed oil has potent anti-histaminic and anti-inflammatory effects, which can successfully treat allergic reactions in different body organs. [3,4] It has been also found from scientific research evidence that treating the allergic condition with black seed reduces mast cell number and decreases the concentration of the different inflammatory mediators in blood plasma.  All these research evidence sufficiently supported the reason for replacing anti-allergic synthetic medication with black seed oil for the chronic allergic condition.
Benefits of Black seed oil in different allergic conditions
The most common allergic reactions include bronchial-constriction which causes asthmatic symptoms, skin rashes, allergic diarrhea and gastric mucosal damage. Black seed and its active phytochemicals can potentially control all these allergic reactions.
Controlling allergen-induced respiratory symptoms with black seed oil treatment
• Excessive histamine release negatively affects the respiratory system and induces broncho-constriction. The usual symptoms of broncho-constriction are quite similar to asthma, which include shortness of breathing, wheezing, uncontrolled coughing, chest congestion etc. Black seed oil antagonizes the histamine-induced broncho-constriction and acts as a bronchodilator.  In addition, black seed oil can reduce the histamine-induced increased eosinophils concentration, Th2 cytokines and IgE and IgG1 antibodies in the lungs. Asthma encouraged by an allergic reaction in the respiratory tract can, therefore, be controlled through treatment by black seed oil. 
• Black seed oil treatment can also control allergic rhinitis symptoms like sneezing, burning sensation in the nose, watery nose and eyes, red eyes and general malaise. 
Treating food allergy with black seed oil treatment
• Allergic diarrhea and gastric mucosal damage are the usual outcomes of food allergy. Almost 2.4% to 4% worldwide general population are often affected with food allergy and the incidence is more common in children. Oral allergy syndrome, vomiting, and diarrhea are the most common symptoms of food allergy, whereas, alcohol consumption often causes gastric mucosal damage. Food allergen often activates and increase the concentration of mast cells present in the small intestine and that trigger allergic reactions. But, black seed oil treatment can decrease the severity of food allergy symptoms and reduce allergic diarrhea by decreasing the number of intestinal mucosal mast cells and inhibiting the level of plasma mast cell protease-1. Therefore, black seed oil treatment can effectively alleviate intestinal allergy symptoms. 
• Gastric damage occurs by the increase in a number of mast cells in the intestine. The alcohol consumption often induces an increase in the level of mast cells concentration as it increases histamine levels and myeloperoxidase activities. But strong antioxidant, antiperoxidative effect, and antihistaminic effects of black seed oil can able to reverse the condition and provide gastro-protective effects. 
I’ve read the colitis and black cumin article in your site. I wanted to say that I completely cured my allergic runny nose by eating nigella sativa.
Nigella sativa is known to cure every disease among Muslim people. Because our Prophet (peace be upon him) said so nearly 1400 years ago. Here is the translation of the hadith:
“Use this black seed regularly, because it is a cure for every disease, except death.” (Sunan Ibn Majah)