Hives All Over Body: Causes, Types & Treatment

What do hives look like?

Hives (urticaria) appear as raised, red or skin-colored welts (wheals) of varying sizes, ranging from a pencil eraser to the size of a dinner plate. They are usually intensely itchy, can appear anywhere on the body, and change shape and location over hours -- individual welts typically resolve within 24 hours and new ones appear elsewhere.

When swelling occurs deeper in the skin -- particularly around the eyes, lips, hands, or throat -- this is called angioedema and can accompany hives. Angioedema of the throat is a medical emergency requiring immediate 911 response. 1Ref 1Zuberbier T, et al. (2022).The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.Definition and classification of urticaria, angioedema association, treatment algorithm with antihistamines and omalizumab, avoidance of long-term corticosteroids, natural history of CSU

What are the most common causes of sudden hives?

Allergic triggers (IgE-mediated): - Foods -- especially peanuts, tree nuts, shellfish, fish, eggs, milk, and wheat - Medications -- particularly penicillin and related antibiotics, aspirin, NSAIDs, and ACE inhibitors - Insect venom -- bee, wasp, or hornet stings - Latex

Infections: Viral infections are a leading cause of acute hives, especially in children. Upper respiratory infections, urinary tract infections, and other viral illnesses can trigger hives as part of the immune response, even when the classic infection symptoms are mild.

Physical triggers: - Cold urticaria (cold air or water), cholinergic urticaria (exercise, heat, sweating), dermatographism (firm scratching raises a linear weal), and pressure urticaria

Idiopathic (no identified cause): In chronic spontaneous urticaria (CSU), a definitive external trigger cannot be found in the majority of cases even after thorough evaluation. 1Ref 1Zuberbier T, et al. (2022).The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.Definition and classification of urticaria, angioedema association, treatment algorithm with antihistamines and omalizumab, avoidance of long-term corticosteroids, natural history of CSU2Ref 2Bernstein JA, Lang DM, Khan DA, Craig T, Dreyfus D, Hsieh F, et al. (2014).The diagnosis and management of acute and chronic urticaria: 2014 update.Diagnostic evaluation for chronic urticaria, limited utility of allergy testing in CSU without a suspected allergen, autoimmune associations in CSU, trigger avoidance as first management step when a cause is identified

Acute versus chronic hives: what is the difference?

Acute urticaria lasts fewer than six weeks. Most cases are caused by infections, allergic reactions, or medications and resolve on their own.

Chronic urticaria persists for more than six weeks and is divided into: - Chronic spontaneous urticaria (CSU): Hives that recur without a clear external trigger. Autoimmune associations, particularly with thyroid disease, are well documented. - Chronic inducible urticaria: Triggered by a specific physical stimulus (cold, pressure, exercise, etc.)

CSU often follows a relapsing-remitting course. Many patients achieve spontaneous remission within one to five years, though some experience symptoms considerably longer. 1Ref 1Zuberbier T, et al. (2022).The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.Definition and classification of urticaria, angioedema association, treatment algorithm with antihistamines and omalizumab, avoidance of long-term corticosteroids, natural history of CSU

How are hives diagnosed and evaluated?

For a first episode of acute hives, a clinical history and physical examination are usually sufficient. If a specific trigger (food, medication, insect sting) is suspected, allergy testing may follow.

For chronic urticaria lasting more than six weeks: - A detailed history focusing on frequency, duration, potential triggers, and accompanying angioedema - Basic laboratory work (CBC, thyroid function, inflammatory markers) to rule out underlying conditions -- though in most cases no specific cause is identified - Formal allergy testing only if an allergen is clinically suspected -- routine allergy panels rarely identify the cause in CSU and are not recommended 2Ref 2Bernstein JA, Lang DM, Khan DA, Craig T, Dreyfus D, Hsieh F, et al. (2014).The diagnosis and management of acute and chronic urticaria: 2014 update.Diagnostic evaluation for chronic urticaria, limited utility of allergy testing in CSU without a suspected allergen, autoimmune associations in CSU, trigger avoidance as first management step when a cause is identified - Referral to an allergist or dermatologist is appropriate for persistent or severe chronic urticaria 1Ref 1Zuberbier T, et al. (2022).The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.Definition and classification of urticaria, angioedema association, treatment algorithm with antihistamines and omalizumab, avoidance of long-term corticosteroids, natural history of CSU

How are hives treated?

First-line: Second-generation oral antihistamines (cetirizine, loratadine, or fexofenadine) are the standard initial treatment. The international EAACI guideline recommends taking them regularly -- not just when welts appear -- and updosing up to fourfold before adding other agents. 1Ref 1Zuberbier T, et al. (2022).The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.Definition and classification of urticaria, angioedema association, treatment algorithm with antihistamines and omalizumab, avoidance of long-term corticosteroids, natural history of CSU

If antihistamines are not sufficient: - Adding an H2 antihistamine (such as famotidine) or a leukotriene receptor antagonist may help - Omalizumab, a biologic targeting IgE, is an approved and highly effective treatment for CSU that does not respond to antihistamines 1Ref 1Zuberbier T, et al. (2022).The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.Definition and classification of urticaria, angioedema association, treatment algorithm with antihistamines and omalizumab, avoidance of long-term corticosteroids, natural history of CSU - Short courses of oral corticosteroids can be used for severe acute episodes but are not appropriate for long-term chronic urticaria management 1Ref 1Zuberbier T, et al. (2022).The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria.Definition and classification of urticaria, angioedema association, treatment algorithm with antihistamines and omalizumab, avoidance of long-term corticosteroids, natural history of CSU

Identifying and avoiding triggers remains the most effective strategy when a specific cause can be confirmed. 2Ref 2Bernstein JA, Lang DM, Khan DA, Craig T, Dreyfus D, Hsieh F, et al. (2014).The diagnosis and management of acute and chronic urticaria: 2014 update.Diagnostic evaluation for chronic urticaria, limited utility of allergy testing in CSU without a suspected allergen, autoimmune associations in CSU, trigger avoidance as first management step when a cause is identified

When should I see a doctor for hives?

See a Gale clinician if:

• Hives recur or persist beyond a week without a clear cause
• They significantly disrupt sleep or daily activities
• You are unsure whether a medication or food is responsible
• You have both hives and facial or throat swelling

Go to an emergency room immediately if hives are accompanied by throat tightening, difficulty breathing, dizziness, or any other sign of anaphylaxis.