Allergic reactions

Anaphylaxis; Anaphylaxis - first aid

Allergic reactions are sensitivities to substances called allergens that come into contact with the skin, nose, eyes, respiratory tract, and gastrointestinal tract. They can be breathed into the lungs, swallowed, or injected.

Allergic reactions

Allergic reaction can be provoked by skin contact with poison plants, chemicals and animal scratches, as well as by insect stings. Ingesting or inhaling substances like pollen, animal dander, molds and mildew, dust, nuts and shellfish, may also cause allergic reaction. Medications such as penicillin and other antibiotics are also to be taken with care, to assure an allergic reflex is not triggered.

Dermatographism - close-up

Dermatographism is a condition where lightly scratching the skin raises wheals or welts. Histamine is released, which causes the small blood vessels (capillaries) to dilate, producing redness and localized swelling.

Dermatographism on the arm

Dermatographism is a condition where lightly scratching the skin raises wheals or welts. Histamine is released at the site, causing the small blood vessels (capillaries) to dilate, producing redness and localized swelling.

Hives (urticaria) on the arm

Hives (urticaria) are raised, red, itchy welts, seen here on the arm. The majority of urticaria develop as a result of allergic reactions. Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.

Hives (urticaria) on the chest

Hives (urticaria) are raised, red, itchy welts, seen here on the chest. The majority of urticaria develop as a result of allergic reactions. Occasionally they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.

Hives (urticaria) - close-up

Hives (urticaria) are raised, red, itchy welts. The majority of urticaria develop as a result of allergic reactions. Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.

Hives (urticaria) on the trunk

This person has raised, red, itchy welts (urticaria) on the chest and abdomen. The majority of urticaria develop as a result of allergic reactions. Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.

Dermatographism on the back

In dermatographism, hives are readily produced if the skin is lightly scratched.

Dermatographism - arm

Wheal formation at the site of light scratching of the skin.

Allergic reactions

Allergic reaction is a sensitivity to a specific substance, called an allergen, that is contacted through the skin, inhaled into the lungs, swallowed or injected. The body's reaction to an allergen can be mild, such as a localized rash, or life-threatening, such as anaphalactic shock.

Considerations

Causes

Symptoms

First Aid

Do Not

When to Contact a Medical Professional

Prevention