Summary

In the Solanaceae family, the genus Capsicum includes C. annuum with common names chili pepper, paprika/sweet pepper, bell pepper, cayenne pepper and jalapeños.

Extensive IgE cross-reactivity among members of C. annuum is anticipated due to their close botanical relationship.

Allergy to Capsicum species is rare. Symptoms can occur after ingestion or inhalation of spice dust.

Route of Exposure

C. annuum is the primary species of genus Capsicum with more than 200 common names in use. The most common include chili pepper, paprika (sweet varieties), bell pepper, cayenne pepper and Jalapeños (Zhigila 2014).

Probably native to the tropics, these peppers produced flavourings that became known in the West through the spice trade. They are now grown mainly in China, Japan, Malaya, the Caribbean, Mexico, Hawaii, the Middle East, and Spain. Chili peppers tend to be eaten in very small amounts as spices or condiments, due to their strong flavours; as opposed to Sweet pepper, which is usually used as a vegetable.

Allergen exposure can occur by ingestion, skin contact or inhalation.

Clinical Relevance

Allergy to Capsicum species is rare. Symptoms can occur after ingestion or inhalation of spice dust. An extensive IgE cross-reactivity between members of C. annuum is expected, e.g. between chili pepper and sweet pepper (Takei 2022).

In a French series of 202 labial food challenges performed in 142 children with suspected food allergy, 156 were positive. The most common foods provoking reactions were egg white (75 cases), peanut (60 cases), mustard (23 cases), cow's milk (13 cases), and cod (8 cases). One child was positive to chili pepper (Rance 1997).

An Indian study of 24 children (aged 3 to 15 years) with documented deterioration in control of their perennial asthma – the purpose of which was to evaluate the possible effect of a specific elimination diet on symptoms – reported that specific IgE was raised to chili in 3 children (12.5%) (Agarkhedkar 2005).

Chili pepper has been implicated as a cause of eosinophilic esophagitis. In a study of 16 men and 7 women aged 18-57, nineteen had serum IgE specific for one or more food-associated allergens (median, 5 foods), with wheat, tomato, carrot, and onion identified most commonly. Sensitisation to chili pepper was documented in 2 cases (9%) (Roy-Ghanta 2008).

A severe asthma attack in a patient with premenstrual asthma was attributed to being triggered by chili pepper (Dikensoy 2001) and an anaphylactic reaction to pickled chili pepper was reported by (Galleani 2023).

‘Hunan hand’ is a contact dermatitis resulting from the direct handling of chili peppers containing capsaicin (Williams 1995) and erythema multiforme-like contact dermatitis has been reported (Raccagni 1995).

Molecular Aspects

Allergen Description

No allergens from chili pepper are described in the International Union of Immunological Societies Allergen Nomenclature ( http://www.allergen.org ).

However, the following allergens have been characterised from C. annuum sweet pepper (http://www.allergen.org), and chili pepper may contain similar allergens resulting in a high degree of IgE cross-reactivity between chili and sweet pepper.

Cap a 1, a thaumatin-like protein (Hoffmann-Sommergruber 2001)

Cap a 2, a profilin (Jensen-Jarolim 1998. Ebner 1998)

Cap a 7, Gibberellin-regulated protein (Takei 2022)

Other allergens detected include a Bet v 1 homologue, (Jensen-Jarolim 1998), an ascorbic acid oxidase and a 1,3-beta-glucanase (Wagner 2004) and a chitinase (Lee 2006).

In a study that demonstrated IgE reactivity to multiple spice allergens in workers exposed to high levels of inhalable spice dust, allergens of approximately 40 and 52 kDa were detected in chili pepper (Van der Walt 2010). Chili pepper IgE-binding proteins between 60 – 100 kDa was detected in (Galleani 2023).

Potential Cross Reactivity

Due to their close botanical relationship (Zhigila 2014, Olatunji 2018), extensive IgE cross-reactivity is expected among members of C. annuum, such as between chili pepper and paprika/sweet pepper (Takei 2022), and cayenne pepper (Airaksinen 2015).

Cross-reactivity to other plants containing the panallergens profilin and Bet v 1 could be expected to occur frequently. Patients with allergy to pepper and associated pollinosis show a high frequency of IgE reactivity to profilin (Wagner 2001).

Reviewed by Dr. Magnus Borres, March 2025