Dermatology and Allergy

An allergy occurs when your immune system overreacts to a normally harmless substance called an allergen. These allergens can be airborne (like pollen), ingested (like peanuts), or come into contact with your skin (like latex).

What are the main symptoms of an allergy?

• Runny or stuffy nose: This is a classic sign of allergies, often accompanied by sneezing and itchy, watery eyes.
• Skin reactions: Hives, redness, and eczema (inflamed, itchy skin) can occur with allergies, especially those triggered by contact with an allergen.
• Respiratory issues: Wheezing, coughing, and difficulty breathing are common symptoms of allergies that affect the airways, like allergic asthma.
• Digestive problems: In food allergies, nausea, vomiting, and diarrhea can occur after ingesting the trigger food.
• Anaphylaxis: In rare cases, a severe allergic reaction called anaphylaxis can occur, causing difficulty breathing, a drop in blood pressure, and even death. This is a medical emergency.

What types of allergies are there?

The wide range of allergens triggers various types of allergies. Here are some common ones:

• Food Allergies: The immune system reacts to a specific food protein, causing symptoms like nausea, vomiting, hives, and in severe cases, anaphylaxis. Common food allergies include peanuts, milk, shellfish, eggs, and wheat.
• Inhalant Allergies: Airborne allergens like pollen, dust mites, pet dander, and mold trigger symptoms like sneezing, runny nose, itchy eyes, and wheezing. Hay fever (allergic rhinitis) is a common inhalant allergy.
• Skin Allergies: Contact with certain substances like latex, nickel, or specific cosmetics can cause skin reactions like redness, itching, and blisters.
• Drug Allergies: Medications can trigger allergic reactions, ranging from mild rashes to life-threatening complications.
• Insect Sting Allergies: Bee stings, wasp stings, and other insect bites can cause localized reactions or severe systemic reactions.

Why is an allergy important?

• Widespread problem: Allergies are a growing public health concern, affecting millions worldwide.
• Quality of life: Allergies can significantly impact daily activities, causing discomfort, sleep disturbances, and anxiety.
• Early diagnosis and management: Proper identification and management can significantly improve a person's well-being and prevent complications like asthma attacks.

What is the prevalence of allergies among the world?

• 30-40%: Estimates suggest that between 30% and 40% of the global population experiences allergies. This translates to hundreds of millions of people worldwide.
• Dramatic Increase: The prevalence of allergic diseases is rising steadily, affecting both developed and developing countries.
• Developed vs. Developing: Developed countries tend to have a higher prevalence, with over 20% of their population affected in many cases. However, allergies are a growing concern in developing countries as well.

How do allergies come about?

The process is called the sensitization process and it consists of the following steps:

1. Initial Exposure: During the first encounter with an allergen, the immune system typically doesn't react.
2. Sensitization: The immune system develops a specific response to the allergen, creating antibodies (proteins) to fight it. This is called sensitization.
3. Overreaction: Upon subsequent exposure to the allergen, the immune system releases histamine and other chemicals, causing allergy symptoms.