Malassezia Sympodialis (Mala s 13) IgE

If you have eczema that keeps coming back on your face, scalp, or neck, there's a fair chance your immune system has learned to react to a yeast that lives on most people's skin. This test checks for one specific piece of that reaction. A positive result means you've made allergy antibodies to that protein, which can change how you and a dermatologist think about stubborn flares.

It also matters if you're about to start dupilumab. This widely used injectable eczema drug calms eczema for many people. In one study, people who already had allergy antibodies to this yeast were far more likely to develop new redness on the face and neck once treatment started. That study used a whole-yeast test, not this single component, so a Mala s 13 result is a narrower clue. This is still a research-grade measurement without standard cutpoints, so it works best as one clue among several.

A Yeast Protein That Looks Like One of Yours

Malassezia sympodialis is one of the most common yeasts living on human skin. It depends on skin oils, so it concentrates on the face, scalp, neck, and upper chest. In most people it causes no trouble at all.

This test measures IgE against one protein the yeast makes, called Mala s 13. IgE is the class of antibody behind allergic reactions. Your body makes yeast-specific IgE only after it has learned to react to the yeast, a state allergists call sensitization. Results are reported in kU/L. That unit is used for allergen-specific antibody levels in blood.

Mala s 13 is the yeast's version of thioredoxin. Nearly every living cell uses thioredoxin for routine chemical upkeep. The yeast and human versions share roughly 45% of their protein sequence, and a few surface patches are nearly identical. Antibodies made against the yeast protein can bind those patches on your own thioredoxin, and on the same protein in the mold Aspergillus. Researchers study this overlap as a model for eczema that keeps smoldering when nothing obvious has changed.

Most research on this yeast measured IgE against a whole-yeast extract, which is a crude mix of its proteins. That whole-extract test (ImmunoCAP m70) is what clinical labs usually run, and a newer version (m227) pools several Malassezia species and picks up slightly more sensitized people. Mala s 13 is one purified component of that mix, used mostly in research and component panels. In one Swedish study of adults with eczema who reacted to the whole extract, 61% also reacted to Mala s 13, more than to any other yeast component on that panel. Other studies more often find Mala s 1, 5, 6, and 9 as the leading components, and Mala s 13 is usually classed as a minor allergen. Findings below that come from whole-extract tests are labeled that way, because they describe a related but broader measurement.

Eczema Severity in Adults

Atopic dermatitis is the chronic, itchy form of eczema that often runs alongside asthma and hay fever. In adults who have it, antibodies to this yeast tend to show up with more severe disease. One study looked at Mala s 13 directly.

Source: Mittermann et al. (all three rows).

What this means for you: a positive Mala s 13 result becomes more common as eczema gets worse, but plenty of people with severe eczema test negative. A negative result on this one component doesn't rule the yeast out as a factor.

Whole-extract studies point the same way. In a study of 199 people with eczema, the 67 adults in the study showed higher yeast IgE levels with higher severity scores, a moderate link (a correlation of 0.429, where 1.0 would be a perfect match). A separate study of more than 600 adults found that people sensitized to skin microbes, this yeast included, had more severe eczema.

Eczema on the Face, Scalp, and Neck

The clearest link is with head and neck eczema. This mostly adult pattern sits right where the yeast is densest. A 2024 pooled analysis of 14 studies and 840 patients found yeast-specific IgE in 79.3% of people with this pattern, higher in studies from outside Asia (88%) than in Asian studies (54.7%). In adult studies, positive results ran from 80% to 100% in head and neck eczema, compared with 13.6% to 42.4% in eczema elsewhere on the body. These figures come from whole-extract tests.

The level itself carries information. In a 2026 study of 121 Korean patients with eczema, higher yeast IgE went with worse head and neck severity, a moderate-to-strong link (0.569), and the link was stronger in adults than in children. In another study of 173 people with eczema, men were sensitized more often than women (58% versus 42%), and sensitization was more common in the head and neck pattern.

What this means for you: if your eczema clusters on your face and neck and keeps returning, a positive result supports the yeast as one driver worth addressing with a dermatologist. It doesn't make the yeast the only cause. These studies show association, so they can't say whether the yeast started the rash or the damaged skin invited the sensitization.

Facial Flares on Dupilumab

Dupilumab is an injectable biologic that blocks a key allergy signal and calms eczema in most people who take it. Some people develop a new red rash on the face and neck after starting it. In a multicentre study that followed adults starting dupilumab, a positive yeast IgE before treatment caught 94.1% of the people who went on to get this facial rash and correctly cleared 87.9% of those who didn't. That study measured whole-yeast IgE, not Mala s 13 specifically, so those numbers should not be read as a validated performance estimate for this component.

In that same whole-yeast study, people who tested positive before treatment had about 11 times the odds of developing the facial rash (odds ratio 11.23).

It can seem backwards that a drug which quiets eczema elsewhere would make the face worse. The two findings fit once you read the yeast antibody as a marker of a particular kind of eczema, one where the yeast on oily facial skin helps keep inflammation going. One proposed explanation is that dupilumab shuts down one branch of the immune response, and a different branch can take over in that yeast-rich skin. A positive result before treatment flags that pattern ahead of time.

What this means for you: if you're considering dupilumab, a positive result on this component doesn't predict the rash as directly as the whole-yeast test did, but it gives you and your dermatologist a reason to watch your face closely and have a plan ready.

Children and Intrinsic Eczema

Sensitization to this yeast is less common early in life. One study of infants and young children with eczema found it in roughly one in six, and adults are sensitized far more often. When it does appear in young children, it tends to show up with extensive, oozing eczema.

In a 10-year follow-up of 187 children who had infant eczema plus milk or wheat allergy, broader eczema in infancy predicted later yeast sensitization. Children who were Malassezia-sensitized at follow-up were also about three times as likely to have ongoing food allergy. For a child with that history, a yeast IgE result in later childhood or adolescence can help explain eczema that persists.

Some people have eczema with no detectable allergies on standard panels. This form is called intrinsic eczema. In a study of 706 people, yeast IgE turned up in both the allergic and the intrinsic forms of eczema, and it was essentially absent in healthy people and in people with other allergic diseases but no eczema.

When Results Can Be Misleading

The biggest source of error is coverage. This test looks at one protein from one yeast species, and several related species live on human skin. A positive result also reflects sensitization, which is different from a yeast infection: the yeast lives on most people, and healthy people rarely carry IgE against it.

• Species gaps: up to 20% of people with eczema who test negative to M. sympodialis react to other skin yeast species such as M. globosa or M. restricta.
• Single-component gaps: Mala s 13 is usually a minor allergen, and even in the study where it ranked highest it picked up 61% of people who reacted to the whole extract, so you can be negative here and positive on the broader test.
• Very high total IgE: people who make a lot of IgE overall tend to have higher yeast-specific readings as well (correlations of 0.51 to 0.67), so a low positive in that setting deserves a second look.
• Different lab platforms: allergen IgE results from different analyzer systems can differ by more than 20%, so only compare results from the same method.

Fasting isn't usually required for allergen-specific IgE blood tests, and a recent meal isn't expected to change this kind of antibody result. Occasionally, other lab factors can affect an antibody result.

Tracking Your Trend

No one has published how much this result naturally varies from one draw to the next in the same person. The research treats yeast sensitization as a longer-term marker, not a day-to-day state. A single reading is a snapshot of where your immune system stands. Because there are no standardized cutpoints for Mala s 13, your own trend is the most useful thing to compare against.

After a baseline, retest in 6 to 12 months if your eczema pattern changes or you start a new treatment. Yearly testing can be reasonable while eczema is active. If you're starting a biologic, test before the first dose. Use the same lab each time.

Whether treating the yeast lowers this specific antibody hasn't been measured directly. A falling number would be hard to interpret unless your skin improves too.

What to Do With a Positive or Unexpected Result

A positive result together with eczema concentrated on the face, scalp, and neck is the combination with the most research behind it. Bring that pairing to a dermatologist or allergist who treats eczema regularly, because it affects treatment choices, especially before a biologic.

A negative Mala s 13 result with stubborn facial eczema doesn't settle the question. Order the whole-yeast extract test and the other yeast components (Mala s 5, Mala s 6, and Mala s 11) to see whether you react to a different part of the yeast. Add total IgE to judge how much of any positive reflects a generally overactive allergy system.

A positive result with no eczema at all is uncommon and hard to interpret, since studies rarely find this antibody in healthy people. Retest to confirm it, check total IgE, and keep an eye on your skin. There's no evidence that treating a lone positive number helps.