During summer, pollen forecasts almost regularly show elevated values for nettles (Urticaceae). Many people become concerned because nettle is a plant that everyone knows and has unpleasant experience with from childhood. But when it comes to pollen allergy, nettle is much milder than its name and frequent appearance in forecasts suggest.

The story about nettle is similar to pine: it produces abundant pollen, but as an allergen it acts weakly. For most allergy sufferers, true nettle is not the main problem.

Which plant we're talking about

"Nettles" in the pollen sense usually means true nettle (Urtica dioica) — the one that stings on contact. The stinging, however, has nothing to do with pollen allergy: it is the result of mechanical hairs and chemical substances in the leaf, not an immune reaction to pollen.

Nettle grows almost everywhere in Croatia — along roads, fences, damp and abandoned places, on the continent and on the coast.

Season

  • from late spring to autumn, with emphasis on summer months
  • peak usually in June, July, and August
  • a long season, similar to other plants in the nettle family

Why it appears more important in forecasts than it really is

Here is the key to reading numbers correctly. Nettle shares a family (Urticaceae) with wall pellitory (Parietaria), and their pollen grains under a microscope are almost indistinguishable. This is why in aerobiological measurements they are often summed and displayed together as "nettles".

Result:

  • a high "nettle" value on the coast is usually actually wall pellitory, which is a strong allergen
  • true nettle (Urtica) contributes to the number, but clinically is much weaker
  • the same number therefore does not mean the same thing in Dalmatia (where wall pellitory dominates) and in the interior (where there is more true nettle)

How strong an allergen it really is

True nettle is considered a weak to moderate allergen. There are people sensitive to nettle pollen, but they are rarer than those sensitive to grasses, olive, or wall pellitory, and symptoms are on average milder.

When a person on the coast has pronounced summer complaints with high nettle values, it is far more likely they are reacting to wall pellitory rather than to true nettle.

Symptoms

When a nettle reaction occurs, it is not different from other pollen allergies:

  • watery nasal discharge and sneezing
  • itching and redness of the eyes
  • itching of the palate
  • rarely — worsening of asthma

Diagnosis

Because of overlap with wall pellitory, targeted testing is important:

  • skin prick tests separately for nettle and for wall pellitory
  • specific IgE tests from blood that distinguish Urtica from Parietaria
  • only this way do you know whether treatment and immunotherapy should be directed at nettle or at wall pellitory

Without this distinction, "allergy to nettles" remains imprecise and can lead to wrong conclusions.

What helps

The approach is the same as with other pollen allergies, when sensitivity is confirmed:

  • Second-generation antihistamines during the season
  • Nasal corticosteroid spray for pronounced symptoms
  • Eye drops for allergic conjunctivitis
  • Removal of nettles from your property reduces local exposure

Specific immunotherapy aimed at true nettle is rarely indicated — when there is significant sensitivity in the nettle family, it usually concerns wall pellitory instead.

Practical recommendations

  • Do not panic over high "nettle" values in the forecast — check whether it is the coast, where wall pellitory is a more likely cause.
  • Stinging from touching nettle has nothing to do with pollen allergy and does not predict it.
  • If summer complaints persist and are severe, insist on testing that distinguishes nettle from wall pellitory.

Note

This is not medical advice. If you suspect you have an allergy to nettle pollen or any other pollen, consult your family physician or allergist. With nettles it is especially important to distinguish true nettle from wall pellitory because they are clinically very different.