Final answer:
An allergic reaction is the likely cause of a patient's epidermal hives and swelling, with potential triggers including airborne allergens, foods, and contact with irritants. Skin testing by allergists is a common method to identify allergens responsible for such reactions. Symptoms range from minor to severe and treatment can vary accordingly.
Step-by-step explanation:
A patient presenting with epidermal hives and swelling without recent contact with other people or pets is most likely experiencing an allergic reaction. Allergic reactions can be triggered by a variety of allergens, which might not necessarily involve direct human or animal contact. For instance, individuals might be allergic to components present in the air, such as pollen, dust mites, or certain chemicals. Food allergies can also cause similar reactions without the need for direct contact with other individuals or animals.
Allergists typically perform skin testing to identify specific allergens related to type I hypersensitivity. In these tests, allergen extracts are introduced into the epidermis and a positive response is usually indicated by the wheal and flare reaction, which includes swelling and redness due to histamine release. In the case of hives, or urticaria, histamine and other mediators from immune cells cause the symptoms.
Eczema is another allergic reaction that can produce itchy, dry patches resembling rashes. Though sometimes associated with dust mite allergy, eczema's precise triggers can be elusive to identify without thorough testing. Symptoms of allergies are varied, ranging from mild, localized issues such as itching and sneezing, to more troubled systemic responses like anaphylaxis. Thus, identifying the cause behind an allergic reaction is important in administering the appropriate treatment, which may include antihistamines, corticosteroids, and in some cases, immunosuppressants.