Top 10 Common Allergies and Their Symptoms (2025 Guide)

TL;DR

• Most reactions fit 10 buckets: pollen, dust mites, pets, mold, cockroach, insect stings, peanuts/tree nuts, milk/egg, shellfish/fish, and medications.
• Clues matter: timing (minutes vs days), place (outdoors vs bed), and pattern (itchy eyes vs stomach pain) help you name the trigger fast.
• First-line relief: non-drowsy antihistamines for hives/itch; steroid nasal spray for hay fever; epinephrine for any throat, breathing, or multi-system reaction.
• Testing is useful when results change your plan (food challenges, immunotherapy, job exposure). Not every sniffle needs a blood test.
• Red flags: swelling of lips/tongue, wheeze, faintness, or rapid spread of hives-use an adrenaline auto-injector and call emergency services.

Itchy eyes in a windy spring, hives after a takeaway, a tight chest after a wasp sting-these aren’t just random annoyances. They’re patterns. Name the pattern and you can act. Below, I break down the 10 most common allergies and what they feel like in real life, so you can spot your culprit and choose your next step with confidence.

What you’re likely trying to do here: figure out which allergy you have, learn the real symptoms (not myths), decide if you need testing, pick treatments that actually work, and know when to seek urgent help. That’s how I’ve shaped this guide. I live in Dunedin, New Zealand-windy days here paint the car yellow with pine dust-so I’ll flag a few Southern Hemisphere quirks as we go.

The top 10 allergies: how they show up, fast clues, and what to watch

Before the list, three quick rules help separate allergy from “something else”:

• Speed: IgE allergies hit fast (minutes to 2 hours). Delayed rashes from nickel or eczema flares can take 12-48 hours.
• Tissue: Allergic rhinitis = nose/eyes; food allergy = skin/gut/breathing; stings = skin then systemic; drugs can be either.
• Repeatable: True allergies recur with the same trigger in similar circumstances.

Population context: Allergic rhinitis affects roughly 20-30% of people worldwide (World Allergy Organization, 2023). Food allergy runs about 5-8% in kids and 2-5% in adults (NIAID/EAACI summaries). Shellfish is the most common adult food allergy; peanut is a top cause in kids in many countries. Self-reported drug allergy is common, but only a small fraction test positive for true IgE allergy (AAAAI notes penicillin “allergy” is confirmed in about 1% of people who report it).

1) Pollen (seasonal allergic rhinitis, “hay fever”)

• Feels like: Sneezing fits, itchy eyes, clear runny nose, nose itch, palate itch. Fatigue from poor sleep.
• When/where: Outdoors on dry, windy days; worse morning/evening. In Dunedin, grass pollen peaks late spring into early summer; cedar/pine dust can coat cars after a nor’wester.
• Look for: “Allergic salute” nose wipe, Dennie-Morgan eye lines, dark circles.
• Red flags: Sinus pain + fever suggests infection, not allergy.

2) Dust mites

• Feels like: Stuffy nose on waking, drip, itchy eyes, wheeze at night. Eczema can flare.
• When/where: Bedrooms, soft furniture, damp houses (common in coastal climates).
• Look for: Relief when traveling to dry places; worse after changing sheets.
• Red flags: Night cough/wheeze-treat asthma seriously.

3) Pet dander (cat/dog)

• Feels like: Instant sneezing, itchy/watery eyes, wheeze around the animal or in homes with pets.
• When/where: Symptoms kick in within minutes; can linger for hours as dander sticks to clothes and furniture.
• Look for: Cat allergy often stronger than dog; reactions even without direct touch.
• Red flags: Chest tightness after exposure-talk to your clinician about asthma control and rescue meds.

4) Mold spores

• Feels like: Nasal congestion, throat irritation, cough, chest tightness. Musty environments make it worse.
• When/where: Damp rooms, bathrooms without extract fans, basements, compost/leaf piles.
• Look for: Black spots on ceilings or window frames; dehumidifier helps.
• Red flags: Fever or shortness of breath with lung symptoms could suggest infection or hypersensitivity pneumonitis-get checked.

5) Cockroach

• Feels like: Year-round sniffles, eye itch, asthma flares in infested homes, especially in urban apartments.
• When/where: Kitchens, warm dense housing. Allergens settle in dust.
• Look for: Infants/children with wheeze in these settings-cockroach exposure is a strong asthma driver.
• Red flags: Frequent night-time asthma symptoms-needs controller medication plan.

6) Insect stings (bee/wasp)

• Feels like: Sharp pain and local swelling is normal. Allergy adds hives away from the sting, lip/tongue swelling, wheeze, dizziness.
• When/where: Gardens, picnics, summer sports. Wasps love sweet drinks; use lids.
• Look for: Reaction within minutes; large local swelling over 10 cm can last days but isn’t the same as anaphylaxis.
• Red flags: Breathing trouble or faintness-use adrenaline and call emergency services. Venom immunotherapy reduces future risk by ~90% (EAACI guidelines).

7) Peanuts and tree nuts

• Feels like: Itch in mouth, hives, swelling, vomiting; sometimes cough/wheeze. Often fast and dramatic.
• When/where: Minutes after eating or even kissing someone who ate nuts.
• Look for: Label reading is non-negotiable; cross-contact in shared kitchens happens.
• Red flags: Any breathing symptom or two-system involvement (skin + gut) = epinephrine first, ambulance second.

8) Milk and egg (common in kids)

• Feels like: Hives, vomiting, crying from gut cramps, eczema flare; sometimes wheeze.
• When/where: Minutes to two hours after ingestion. Baked egg/milk may be tolerated by some kids.
• Look for: Many kids outgrow milk/egg by school age. Regular re-evaluation matters.
• Red flags: Poor growth, bloody stools, or delayed eczema without hives may be non-IgE allergy-testing and dietitian input help.

9) Shellfish and fish

• Feels like: Hives, swelling, nausea/vomiting, risk of anaphylaxis. Steam from cooking can trigger reactions in sensitive people.
• When/where: Restaurants, fish markets; cross-contact on grills or fryers is common.
• Look for: Shellfish (crustaceans) allergy tends to persist into adulthood. Iodine contrast allergy is unrelated to shellfish-common myth.
• Red flags: Wheeze or throat tightness-adrenaline now.

10) Medications (penicillin, other antibiotics; NSAIDs)

• Feels like: Immediate hives, swelling, wheeze (IgE). Or delayed rashes days into the course (T-cell). NSAIDs can cause hives/asthma through non-allergic mechanisms too.
• When/where: During a course, often early for IgE; delayed for non-IgE.
• Look for: Up to 90% of people labeled “penicillin allergic” are not allergic when tested (AAAAI). De-labeling opens safer, cheaper options.
• Red flags: Mucosal sores, skin peeling, or fever with rash (e.g., SJS/TEN) are emergencies-seek urgent care.

Decide what to do: tests, treatments, and smart trade-offs

Here’s a simple decision path I use when friends ask for help (and yes, I get those texts a lot):

1. Is it likely allergic? Fast, repeatable reactions with itch or sneeze point to allergy. Slow, bloaty gut discomfort after milk without hives? Think intolerance.
2. Can you avoid it? If yes, do that now. If not, choose the best symptom control while you plan testing.
3. Any danger signs? Breathing issues, swelling of lips/tongue, dizziness-use an adrenaline auto-injector and call an ambulance.

Testing: when and what

• Skin-prick testing (SPT): Best for inhalants (pollen, mites, pets) and many foods. Quick results in 15-20 minutes. Not great if you’re on strong antihistamines or have extensive eczema at test sites.
• Specific IgE blood tests: Useful if you can’t stop antihistamines or have skin issues. Component testing (e.g., Ara h 2 for peanut) can clarify risk levels.
• Oral food challenge: Gold standard for food allergy diagnosis when history/testing conflict. Only do this under specialist supervision.
• Penicillin challenge/de-labeling: Worth pursuing if you’ve been labeled allergic. Studies show most are not, which widens safe antibiotic choices (CDC/AAAAI).
• Patch testing: For delayed contact allergies (nickel, fragrance), not for immediate hay fever-type symptoms.

Decision criteria: which test is best for your case?

• Clear history + low stakes (e.g., cats make you sneeze): You often don’t need lab tests-try avoidance and meds first.
• Unclear food reactions or high stakes (school policies, severe episodes): Seek SPT/sIgE and consider a supervised challenge.
• Severe sting reaction: Ask about venom testing and immunotherapy; it cuts future life-threatening reactions dramatically (EAACI).
• Chronic hives without clear trigger: Extensive allergy testing usually doesn’t help. Focus on daily antihistamines and triggers like NSAIDs, heat, or pressure.

First-line treatments that work

• Antihistamines (non-drowsy): Cetirizine, loratadine, fexofenadine help hives and sneezing. Great as needed; in tough seasons, daily beats “only when bad.”
• Nasal steroid sprays: Most effective for hay fever congestion and drip. Use daily, proper technique, give it a week. Cochrane reviews back their top-tier efficacy.
• Eye drops: Antihistamine/mast-cell stabilizer drops ease itchy, watery eyes fast.
• Asthma control: If allergies trigger wheeze, a preventer inhaler plan matters more than doubling down on reliever puffs.
• Adrenaline auto-injector: For anyone with food/sting/drug anaphylaxis risk. Practice with a trainer device; replace before expiry.
• Topical steroids/calcineurin inhibitors: For eczema flares, short courses calm inflammation so moisturizers can keep skin stable.

Immunotherapy: when to consider it

• Best for: Pollen, dust mites, cat/dog dander, and venoms when symptoms persist despite meds and avoidance. Both shots and tablets (for some pollens/mites) exist.
• Not for: Food allergies (except in select specialist protocols), chronic hives, or non-allergic rhinitis.
• Trade-offs: Time commitment (3-5 years), cost, and rare systemic reactions vs long-term relief and asthma risk reduction.

Environmental fixes that actually move the needle

• Dust mites: Zip mattresses/pillows in allergen-proof covers; hot-wash sheets weekly; keep indoor humidity under ~50%; consider a dehumidifier in damp climates like coastal Otago.
• Pollen: Keep windows shut on high-count days; shower and change clothes after outdoor time; wear wraparound sunglasses; use a HEPA purifier in the bedroom during peak season.
• Pets: Pet-free rooms (especially the bedroom), HEPA vacuum, wash pets weekly if tolerated. Rehoming is a hard conversation but sometimes the only fix for severe asthma.
• Mold: Fix leaks, use extractor fans, clean visible mold safely, and run a dehumidifier. If musty smell persists, check hidden cavities.
• Cockroach: Seal entry points, store food airtight, remove clutter, use bait stations; professional pest control if needed.

Medication choices: best for / not for

• Nasal steroids: Best for congestion/drip; not for instant eye itch alone.
• Oral antihistamines: Best for hives/itch; not great alone for blocked nose.
• Decongestant sprays: Best for short bursts (max 3-5 days) in bad congestion; not for long-term-risk of rebound.
• Montelukast: Can help allergic rhinitis with asthma; not first-line for isolated hay fever; watch for mood side effects.
• NSAIDs: Avoid if you have NSAID-exacerbated respiratory disease (wheeze/face swelling after ibuprofen/aspirin); use acetaminophen instead-ask your clinician.

Southern Hemisphere timing tips

• Pollens run roughly September to January in NZ; ryegrass leads the charge. Mould and dust mites spike with damp winters.
• Set reminders in late August to start your nasal spray two weeks before symptoms usually hit; being early beats playing catch-up.

Quick reference: checklists, red flags, mini‑FAQ, and next steps

One-minute symptom matcher

• Itchy eyes + sneezing fits, clear drip, no fever → Pollen/pets/dust mites; try antihistamine + nasal steroid, check exposure pattern.
• Wheezing at night, morning stuffiness → Dust mites/mold; bedroom controls + asthma review.
• Hives minutes after a food, plus vomiting or cough → Food allergy; carry adrenaline, see an allergist.
• Big local swelling after a sting only → Likely local reaction; cold pack + antihistamine; see a specialist if reactions escalate.
• Rash days after starting an antibiotic → Possible delayed drug reaction; stop and seek advice before taking similar meds again.

Red flags you don’t argue with

• Lip/tongue swelling, trouble breathing, wheeze, faintness, tight throat, or a combination of skin + gut + breathing symptoms after exposure.
• Dark red/purple rash with fever or skin peeling after starting a medication.
• Asthma symptoms that wake you at night more than once a week-this is control failure.

What to try today (safe, evidence-backed)

• Buy a non-drowsy antihistamine and a steroid nasal spray; use both correctly for 1-2 weeks before judging.
• Set up your bedroom: allergen covers, weekly hot washes, and a HEPA purifier if you have a furry pet or pollen issues.
• Log reactions: time, food/setting, onset, and symptoms. Patterns jump off the page in a week.

Common pitfalls to avoid

• Relying only on antihistamines for a blocked nose-nasal steroids do the heavy lifting.
• Chasing blood tests for chronic hives-most cases aren’t IgE-driven and don’t need a giant panel.
• Accepting a “penicillin allergy” label for life-ask about de-labeling; it changes future care.
• Stopping inhaled steroids when you feel good in spring-season changes fast; keep your plan.

Mini‑FAQ

Is it an allergy or a cold?
Colds bring fever, sore throat pain, aches, and thick discolored mucus after a day or two. Allergies itch, start fast, and the mucus stays clear. If symptoms last over two weeks and you’re not sick, think allergy.

Can adults suddenly develop food allergies?
Yes. Shellfish is the most common new adult food allergy, but nuts and fruits can appear, too. New throat tightness after eating needs urgent attention.

Do hypoallergenic pets exist?
Not really. All cats and dogs make allergenic proteins. Some breeds shed less, but protein levels vary by animal, not breed.

Is iodine contrast unsafe with shellfish allergy?
No. That’s a myth. Shellfish reactions are to muscle proteins (tropomyosin). Contrast reactions aren’t related to iodine or shellfish proteins.

Should I avoid peanuts during pregnancy or breastfeeding?
Guidelines in recent years encourage early peanut introduction for infants at risk (after medical advice). Routine avoidance in pregnancy/breastfeeding isn’t recommended solely to prevent allergies (NIAID/EAACI).

Do air purifiers help?
HEPA purifiers help with dander and pollen in a closed room. They don’t fix dust mites in mattresses or mold in damp walls-address the source, too.

When do I need an allergist?
Severe reactions (any breathing issues), unclear food triggers, frequent asthma flares, or interest in immunotherapy are good reasons to see a specialist.

Scenarios and trade-offs

• Pets you love vs symptoms you hate: Start with strict bedroom ban + HEPA + weekly wash. If asthma stays uncontrolled, discuss immunotherapy or rehoming. Health comes first.
• Dust mite mattress covers vs new mattress: Covers are cheaper and effective; a new mattress without covers won’t solve the problem.
• Daily meds vs immunotherapy: Meds give quick relief; immunotherapy is a long play that can change the trajectory. Choose based on severity, time, and cost.

How I handle this at home

Our place in Dunedin gets damp in winter, so we run a dehumidifier and cracked the habit of drying clothes indoors. Spring means sunglasses on windy days and a nasal spray starting late August. If a wasp lands on our picnic, I tip the drink rather than gamble. Small habits beat big regrets. Silvia is the label-checker in the house; two sets of eyes save you from “may contain” surprises.

Credibility snapshot

• World Allergy Organization 2023 report: Allergic diseases affect up to one in three people.
• AAAAI guidance: Most penicillin “allergy” labels are incorrect; testing is safe and effective.
• NIAID/EAACI: Early peanut introduction reduces peanut allergy risk in infants with eczema/egg allergy.
• Cochrane reviews: Intranasal corticosteroids outperform antihistamines for nasal congestion.

Next steps

• Map your pattern: Note trigger, onset, and symptoms for 7-10 days.
• Start the basics: Daily nasal steroid + non-drowsy antihistamine if needed; bedroom controls.
• Plan testing if decisions depend on it: Food challenges, penicillin de-labeling, or venom testing.
• Prepare for emergencies: Get an auto-injector if you’ve had a systemic reaction; teach family how to use it.

Troubleshooting

• Still congested after a week on a nasal spray? Check technique: Aim slightly out toward the ear, sniff gently, and use daily. Add saline rinses before the spray.
• Antihistamine “not working”? For hives, some clinicians advise up-titration within labeled guidance. If daily hives persist 6+ weeks, ask about chronic spontaneous urticaria protocols.
• Asthma keeps flaring with allergies? You may need a preventer adjustment; book a review and check inhaler technique.
• Unsure if it’s food or infection? Time the symptoms. Allergy hits fast and repeats; infection brings fever and lasts regardless of what you eat.

You came here to name the problem and act. You’ve got the patterns, the red flags, and the steps that make a difference. Pick one change today-better nasal spray use, allergen covers, booking that penicillin test-and you’ll feel that difference fast.