Can allergies make you tired?

How allergies cause it

AAFA’s Ask the Allergist service says allergies can cause tiredness and fatigue mainly because of nasal congestion and other allergy symptoms, which can cause sleep-disordered breathing and waking up often during the night.¹ When you are sniffling, sneezing and generally feeling poorly, you often don’t sleep well.² The result can be poor overall sleep quality, then sleepiness and fatigue during the day.¹ ACAAI lists fatigue among hay fever symptoms, often reported because a blocked nose leads to poor-quality sleep.³ You might not connect daytime allergy symptoms with a lack of sleep at night.²

The link can run both ways. A 2024 review describes a high rate of sleep problems such as insomnia in people with allergic rhinitis.⁴ Poor sleep can make nasal symptoms worse, and the two can form a vicious cycle.⁴ The review names nasal congestion as the most direct cause of these sleep problems.⁴

Sleep is not the only route. An allergic reaction can also release chemicals in your body that cause fatigue.²

The effects can reach beyond feeling worn out. ACAAI says allergic rhinitis can be associated with decreased concentration and focus, limited activities, decreased decision-making capacity, impaired hand-eye coordination, problems remembering things, irritability, sleep disorders, fatigue, missed days of work or school, more motor vehicle accidents and more school or work injuries.³

Both seasonal and year-round allergies can cause fatigue.² A specific tree, grass or weed pollen can set off symptoms only at a certain time of year.² One of the most common molds that cause allergies peaks in late summer, in August and early September.² Year-round symptoms can be linked to indoor sources such as dust mites, cockroaches, mice, pets and mold.²

Allergies or something else?

Fatigue is a feeling of weariness, tiredness or lack of energy.⁵

The flu and colds can also leave you tired.⁶ With the flu, fatigue and weakness are usual, the illness tends to start abruptly, and fever and aches are usual too.⁶ With a cold, fatigue and weakness happen only sometimes, and fevers are rare.⁶ Hay fever does not cause a fever.³

Many other conditions can leave you tired. ACAAI’s list of other possible causes to rule out includes anemia, anxiety, autoimmune disorders such as lupus, chronic infections, concussion, depression, diabetes, heart disease, multiple sclerosis, rheumatoid arthritis and related disorders, sleep disorders and thyroid disorders.²

When to see a doctor

If you have been feeling tired for weeks, contact your health care provider.⁵

Getting tested by a board-certified allergist is the first step to finding relief, according to ACAAI.² If an allergist rules out allergies, it is important to see a doctor about other possible causes.²