Eating bananas may trigger a food allergy in some people and cause eczema, a skin condition or rash that includes redness, brown-gray patches, tiny bumps and scales, states Mayo Clinic. Itchy skin rashes can affect the mouth in people experiencing cross-reactions involving bananas and ragweed pollen.
Eczema, also known as atopic dermatitis, caused by a banana allergy can affect a person's hands, wrists, inner elbows, feet, ankles and inner knees, notes Mayo Clinic. A breakout can also affect the neck, top chest and eyelids. In some people, exercising can trigger a banana allergy, a situation remedied by eliminating the food or eating it a few hours beforehand.