Catamenial Anaphylaxis: Why Your Allergy Spikes During Your Period
Published: 20 March 2026 · Reviewed for clinical accuracy · Written for UK patients
What Is Catamenial Anaphylaxis?
Catamenial anaphylaxis is a rare but clinically recognised condition in which severe allergic reactions — including anaphylaxis — occur in a cyclical pattern linked to the menstrual cycle. The term "catamenial" derives from the Greek word for monthly, and the condition typically presents during the luteal phase or at the onset of menstruation, when progesterone levels fluctuate significantly. It is sometimes associated with an underlying sensitivity to endogenous progesterone.
If you have ever noticed that your allergic reactions seem to worsen at a particular point in your cycle, you are not imagining it. For some individuals, catamenial anaphylaxis can represent a genuinely distressing and under-recognised pattern that may benefit from further investigation through appropriate testing.
Why Do Allergies Get Worse During Your Period?
The relationship between the menstrual cycle and allergic reactions is rooted in the interplay between reproductive hormones and the immune system. Understanding this connection can help contextualise why period allergy flare-ups occur.
The Progesterone–Histamine Connection
Progesterone, which rises sharply after ovulation, can influence mast cell behaviour. Mast cells are the immune cells responsible for releasing histamine — the chemical that drives allergic symptoms such as hives, swelling, and breathing difficulties. For a deeper understanding of how histamine drives symptoms, see our guide on histamine intolerance vs IgE allergy. Research suggests that in susceptible individuals, progesterone may act as a trigger that destabilises mast cells, leading to increased histamine release.
Oestrogen's Role in Histamine Regulation
Oestrogen and histamine have a bidirectional relationship. Oestrogen can stimulate mast cells to release histamine, while histamine itself can promote oestrogen production. During the premenstrual phase, shifting oestrogen-to-progesterone ratios may amplify this cycle, which can sometimes highlight underlying allergic tendencies that remain subclinical at other times of the month. This hormonal-immune interplay is also relevant in conditions like PCOS, where systemic allergic inflammation may share overlapping pathways.
Key Hormonal Phases and Allergy Risk
| Menstrual Phase | Dominant Hormone | Potential Allergy Impact |
|---|---|---|
| Follicular (Days 1–13) | Oestrogen rising | Generally lower allergy activity for most individuals |
| Ovulation (Day 14) | Oestrogen peak, LH surge | Some individuals may notice mild symptom changes |
| Luteal (Days 15–28) | Progesterone dominant | Higher risk of mast cell activation and allergy flare-ups |
| Menstruation (Days 1–5) | Hormone withdrawal | Anaphylactic episodes most commonly reported in this window |
Recognising the Signs: What Cyclical Anaphylaxis May Look Like
Catamenial anaphylaxis can present with a range of symptoms that may vary in severity from cycle to cycle. It is important to note that these symptoms can also be associated with many other conditions, so professional assessment is always recommended.
Symptoms that may recur in a cyclical, menstrual-related pattern can include:
- Urticaria (hives) appearing in the days before or during menstruation
- Angioedema — swelling of the lips, face, or throat
- Respiratory symptoms such as wheezing or breathlessness
- Gastrointestinal discomfort including cramping or nausea beyond typical menstrual symptoms
- Hypotension (low blood pressure) in severe episodes
- Full anaphylaxis requiring emergency intervention
Catamenial Anaphylaxis vs General Allergy Flare-Ups
It is worth distinguishing between catamenial anaphylaxis and the more common experience of worsening allergy symptoms during menstruation.
| Feature | Catamenial Anaphylaxis | Cyclical Allergy Worsening |
|---|---|---|
| Severity | Potentially life-threatening anaphylaxis | Mild to moderate symptom increase |
| Timing | Strictly cyclical, often perimenstrual | May vary, less predictable |
| Trigger | Often endogenous progesterone | External allergens amplified by hormonal shifts |
| Prevalence | Very rare | Relatively common in allergic individuals |
| Testing approach | May include specific IgE, tryptase, hormonal panels | Standard allergy blood testing may be helpful |
| Medical urgency | Requires urgent medical care if symptoms are severe | May warrant allergy review and monitoring |
Who Should Consider Testing?
Testing may be particularly worthwhile for individuals who notice a consistent pattern between their menstrual cycle and allergic symptoms. You may wish to consider allergy testing if you:
- Experience unexplained allergic reactions that seem to follow a monthly pattern
- Have a known allergy history that worsens significantly at specific times of the month
- Have experienced one or more episodes of anaphylaxis without an identifiable external trigger
- Notice that standard allergy management does not fully account for the cyclical nature of your symptoms
- Want to establish baseline allergy and inflammatory markers for future reference
In London and across the UK, accessing private allergy testing can sometimes offer a more timely route to gathering this baseline information, particularly when NHS waiting times may be extended.
What Tests Can Help?
While catamenial anaphylaxis itself is a clinical diagnosis that requires comprehensive medical assessment, certain blood tests can provide valuable supporting information. Our clinic provides testing and reporting only — results should always be reviewed with an appropriate healthcare professional.
Tests that may be relevant include:
- Total IgE — a general marker that can sometimes indicate allergic predisposition
- Specific IgE panels — to identify or rule out sensitivities to common allergens such as foods, latex, or environmental triggers
- Serum tryptase — a marker that may be elevated following mast cell activation; baseline levels can be useful for comparison. Learn more about tryptase levels and anaphylaxis
- Hormonal panels — including progesterone and oestradiol levels
- Full blood count with differential — eosinophil levels can sometimes suggest an allergic or inflammatory component
How Often Should Testing Be Repeated?
For individuals with suspected hormone-related allergies, a single set of results may not capture the full picture. The cyclical nature of catamenial anaphylaxis means that:
- Initial baseline testing can help establish reference values
- Repeat testing at different cycle phases may sometimes highlight hormonal and immunological fluctuations
- Annual review of key allergy markers can be helpful for ongoing monitoring, particularly if symptoms change over time
Frequently Asked Questions
What is catamenial anaphylaxis?
Catamenial anaphylaxis is a rare condition where severe allergic reactions, including anaphylaxis, occur in a cyclical pattern linked to the menstrual cycle. It is most commonly associated with the luteal or menstrual phase and may involve sensitivity to the body's own progesterone.
Can your period really make allergies worse?
Yes, hormonal fluctuations during the menstrual cycle can influence immune function and mast cell behaviour. Many individuals with existing allergies notice that symptoms such as hives, hay fever, or food sensitivities may intensify during the premenstrual or menstrual phase.
What blood tests are useful for period-related allergy flare-ups?
Tests that may provide helpful information include total IgE, specific IgE panels, serum tryptase, hormonal panels (progesterone, oestradiol), and a full blood count with eosinophil differential. Learn more about understanding total IgE vs specific IgE.
Is catamenial anaphylaxis the same as progesterone allergy?
They are closely related but not identical. Catamenial anaphylaxis describes the cyclical pattern of severe allergic reactions, while progesterone hypersensitivity refers specifically to an immune-mediated reaction to endogenous progesterone.
How common is catamenial anaphylaxis in the UK?
It is considered rare, with relatively few cases formally documented in medical literature. However, some experts believe it may be under-recognised, particularly when cyclical symptoms are attributed solely to other causes.
Should I get tested during a specific phase of my cycle?
Testing during both a symptomatic phase and a symptom-free phase can sometimes provide more informative comparative data. Discuss the optimal timing with the healthcare professional overseeing your care.
Where can I get allergy testing in London?
Private allergy testing in London is available at our clinic. We provide blood-based allergy testing and detailed reporting. Results can be shared with your GP or specialist to support your ongoing care pathway.
What should I do if I experience anaphylaxis during my period?
If you experience symptoms of anaphylaxis — including difficulty breathing, swelling of the throat, or collapse — call 999 and seek emergency medical care immediately. Following any acute episode, consider discussing the pattern of your reactions with an appropriate healthcare professional.
Concerned About Cyclical Allergy Symptoms? Explore Testing Options
If you've noticed that your allergic reactions follow a monthly pattern linked to your menstrual cycle, allergy blood testing may help establish baseline markers and support further clinical assessment.
Explore Our Testing OptionsMedical disclaimer: This article is for general information only and does not constitute medical advice, diagnosis, or treatment. AllergyClinic.co.uk provides nurse-led venous blood sample collection and laboratory reports. We do not offer doctor or GP consultations, clinical interpretation of results, prescribing, or treatment planning as part of our test bookings. Always consult a qualified healthcare professional — such as your GP or an NHS/private allergy specialist — for interpretation of your results, clinical guidance, and a personalised management plan.
If you are experiencing a medical emergency, call 999 (UK) or 112 (EU) immediately.
