Stemphylium herbarum

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Code: m10
Latin name: Stemphylium herbarum/S.botryosum
Source material: Spores and mycelium
Family: Pleosporaceae

Allergen Exposure

S. herbarum and closely-related S.botryosum are cosmopolitan


A mould, which may result in allergy symptoms in sensitised species of mould, very common in temperate and subtropical regions and found on a wide range of host plants. Soil isolates have been reported from forests, grasslands, decaying vegetation, wheat plantings, beet and citrus cultivation and coffee plantations. It has also been isolated from polluted fresh water, leaf litter of trees, and bark and leaves of citrus. As a typical seedborne fungus, it is seen on tomato (black mould rot), wheat and barley.

There are 33 published names that represent recognisable taxa of Stemphylium. In species with known teleomorphs such as Stemphylium, the sexual state is Pleospora, i.e. S. herbarum ~ Pleospora herbarum. (1)

S. herbarum and other members of this genus, e.g. S. solani, S. botryosum and S. vesicarium, are well-known plant pathogens. They may be found growing on a wide range of vegetables including tomato, lettuce, beans, pea, etc. Some species are plant pathogens that cause leaf spot diseases, e.g. Stemphylium leaf blight, caused by (among others) S. vesicarium, which typically attacks leaf tips.

Together with Alternaria, Stemphylium is considered one of the most important mould allergens in the United States.

The mycelium hyphae are mainly colourless (but can also be yellowish-brown), 2-9 µm thick, with numerous septa. Colonies are rapid-growing, darkening into brown to olive-black or greyish, and suede-like to covered with tufts of soft hair (floccose). Microscopically, solitary, darkly pigmented, terminal, multicellular conidia (dictyoconidia) are formed on a distinctive conidiophore with a darker terminal swelling. Stemphylium should not be confused with Ulocladium which produces similar dictyoconidia from a sympodial conidiophore, not from a conidiogenous cell as in Stemphylium. (2)

The conidia are violently discharged after a lowering of the relative humidity in the presence of light.

Allergen Description

No allergens have been characterised from this mould.

Ste h 1 and Ste b 1 are Alt a 1-related allergens (from Alternaria alternata); they have not been characterised, but have been implied from cross-reactivity studies. (3, 4, 5)

Stemphylium botryosum spores release allergen before germination. The extent to which human exposure occurs to allergens eluted from inhaled spores or from hyphae that germinate after deposition in the respiratory tract is unknown. (6)

Potential Cross-Reactivity

Shared allergenic fractions and antigenic determinants have been shown to be present in Alternaria and Stemphylium, in particular an Alt a 1-like protein in the latter. (7, 8)

Partial cross-reactivity and/or shared antigens among several fungal species, including Alternaria tenuis, Stemphylium sp., Curvularia sp., and Aspergillus fumigatus, has been reported. (9) Several studies have reported cross-reactivity between A. alternata, Stemphylium and Curvularia. (10) Studies have shown cross-reactivity with Alternaria tenuis, showing shared antigens with Stemphylium, Spondylocladium, Curvularia, and Helminthosporium. (11)

Clinical Experience

IgE-mediated reactions

Anecdotal evidence suggests that S. herbarum may induce symptoms of asthma and hypersensitivity pneumonitis in sensitised individuals; however, few studies have been reported to date for S. herbarum, and evidence is gathered from the closely-related species S. botryosum and studies of uncharacterised Stemphylium. (12, 13) It is possible that the allergy occurs more frequently than has been reported, as Stemphylium (together with Alternaria) is considered one of the most important mould allergens in the United States. (7) In two groups of Swedish patients, Stemphylium was found to be a frequent sensitizing agent. (13)

In an early study that queried whether immediate respiratory allergy to Stemphylium existed, 39 children with positive cutaneous and/or serum-specific IgE for Stemphylium were examined. Provocation tests were positive in 19 patients (14 boys and 4 girls, 10 to 16 years old) with a respiratory sensitivity: 6/10 by passive anterior rhinomanometry and 13/15 by bronchial tests. Clinical symptoms were asthma and intermittent rhinitis (14/19), predominantly from June to August. Specific hyposensitisation was conducted in 14 children (for 3 years in 10 cases). (14)

From a large Phadia repository of human blood serum, a subset was compiled to include the maximal numbers of individual blood sera, which had been tested consistently across the largest panel of fungal allergen preparations. Of those individuals with a positive test of at least >0.35 kUA/L comprising 668 unique samples (devoid of clinical history), 367 were shown to have raised IgE to S. herbarum. (15) Of 121 Finnish suspected mould-allergic children with asthma, 40.5% were positive for a mould screen. Stemphylium was positive in 22%. (16)

In a study of 1311 asthmatics with atopy and positive skin reaction to fungal spores in Thessaloniki, Greece, 421 (32%) were positive to a mould panel. Positive skin reaction to Alternaria species was observed in 177 patients (13.5%), in 98 (7.4%) to Cladosporium, 65 (5%) to Aspergillus, 45 (3.4%) to Fusarium and 36 (2.7%) to Rhizopus. Stemphylium represented less than 1% of the atmospheric collections. (17)

A retrospective evaluation of skin-prick test results in 75 consecutive patients from a tertiary referral medical centre in Texas reported that of the 67 evaluable patients, 58 (86.6%) had a positive skin test to at least 1 antigen. The most common positive skin tests were in response to cockroach, Dermatophygoides farinae, Bermuda grass, false ragweed, mesquite, Stemphylium, Curvularia, short ragweed, and Timothy grass. (18)

Quincke's edema due to Alternaria and Stemphylium has been described. (19)

Allergic bronchopulmonary aspergillosis due to the closely-related species member Stemphylium lanuginosum has been reported. (20)

Other reactions

None reported.


Compiled by Dr Harris Steinman.


  1. Câmara MP, O'Neill NR, van Berkum P. Phylogeny of Stemphylium spp. based on ITS and glyceraldehyde-3-phosphate dehydrogenase gene sequences. Mycologia. 2002;94(4):660-72.
  2. McGinnis, MR. Laboratory handbook of medical mycology. Academic Press, London, UK.
  3. Hong SG, Cramer RA, Lawrence CB, Pryor BM. Alt a 1 allergen homologs from Alternaria and related taxa: analysis of phylogenetic content and secondary structure. Fungal Genet Biol 2005;42(2):119-29.
  4. Asturias JA, Arilla MC, Ibarrola I, Eraso E, Gonzalez-Rioja R, Martinez A. A sensitive two-site enzyme-linked immunosorbent assay for measurement of the major Alternaria alternata allergen Alt a 1. Ann Allergy Asthma Immunol 2003;90(5):464-5.
  5. Saenz-de-Santamaria M, Postigo I, Gutierrez-Rodriguez A, Cardona G, Guisantes JA, Asturias J, Martinez J. The major allergen of Alternaria alternata (Alt a 1) is expressed in other members of the Pleosporaceae family. Mycoses 2006;49(2):91-5.
  6. Green BJ, Mitakakis TZ, Tovey ER. Allergen detection from 11 fungal species before and after germination. J Allergy Clin Immunol 2003;111(2):285-9.
  7. Agarwal MK, Jones RT, Yunginger J W. Shared allergenic and antigenic determinants in Alternaria and Stemphylium extracts. J Allergy Clin Immunol 1982;70(6):437-44.
  8. Schmechel D, Green BJ, Blachere FM, Janotka E, Beezhold DH. Analytical bias of cross-reactive polyclonal antibodies for environmental immunoassays of Alternaria alternata. J Allergy Clin Immunol 2008;121(3):763-8.
  9. Schumacher MJ, Farr RS, McMlatchy JK, Minden P. Primary interaction between antibody and components of Alternaria. II. Antibodies in sera from normal, allergic, and immunoglobulin-deficient children. J Allergy Clin Immunol 1975;56(1):54-63.
  10. Wijnands LM, Deisz WD, Van Leusden FM. Marker antigens to assess exposure to molds and their allergens. II. Alternaria alternata. Allergy 2000;55(9):856-64.
  11. Bonilla Soto O, Rose NR, Arbesman CE. Allergenic molds: Antigenic and allergenic properties of Alternaria tenuis. J Allergy 1961;32:246-70.
  12. Prince HE, Talbott G, Browning WH, Holman J, Weiner A, Morrow MB, Youngman RA. Comparative skin tests with two Stemphylium species. Ann Allergy 1971;29(10):531-4.
  13. Karlsson-Borga A, Jonsson P, Rolfsen W. Specific IgE antibodies to 16 widespread mold genera in patients with suspected mold allergy. Ann Allergy 1989;63:521-6.
  14. Lelong M, Henard J, Wattre P, Duprey J, Thelliez P, Miersman R. Does immediate-type respiratory allergy occur regarding Stemphylium? Evaluation of 39 challenge tests. [French] Allerg Immunol (Paris) 1986;18(8):21, 23, 25-6.
  15. Soeria-Atmadja D, Onell A, Borga A. IgE sensitization to fungi mirrors fungal phylogenetic systematics. J Allergy Clin Immunol 2010;125(6):1379-86.
  16. Koivikko A, Viander M, Lanner A. Use of the extended Phadebas RAST panel in the diagnosis of mould allergy in asthmatic children. Allergy 1991;46:85-91.
  17. Gioulekas D, Damialis A, Papakosta D, Spieksma F, Giouleka P, Patakas D. Allergenic fungi spore records (15 years) and sensitization in patients with respiratory allergy in Thessaloniki-Greece. J Investig Allergol Clin Immunol 2004;14(3):225-31.
  18. Calhoun KH. Patterns of mold sensitivity in the subtropical Gulf Coast. Otolaryngol Head Neck Surg 2004;130(3):306-11.
  19. Gaudibert R. Quincke's oedema due to Alternaria and Stemphylium. [French] Rev Fr Allergol 1971;11(1):75-7.
  20. Lahoute C, Tonnel AB, Fournier E, Ramon P, Voisin C. Bronchopulmonary pathology with hypereosinophilia of fungal origin (excluding allergic bronchopulmonary aspergillosis. [French] Poumon Coeur 1983;39(2):87-93.


As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.