Reviewed January 2015

We have a police detective who used to sneeze and get itchy eyes with exposure to marijuana (smoked or not-smoked). After her pregnancy, she now develops gen'l pruritus followed by rapid progression to hypotension with loss of consciousness. Since a skin test extract is not available, do you know how one can be prepared? Or of a specialized lab that could run a specific IgE? Her tryptase is normal, total IgE is 159, and has a history of mild SAR to ragweed and trees that is controlled with loratadine. Other than avoidance, are there any treatment options? She doesn't plan on being exposed to marijuana, but in her line of work, it happens.


Thank you for your recent inquiry.

Actually, Cannibis (marijuana) allergy has been reported a number of times in the literature, and skin test protocols as well as research in vitro tests have been used to demonstrate that reactions can be IgE-mediated. For your convenience, I have copied several abstracts below which have presented cases of marijuana allergy and which present skin test proceedures.

You could actually use raw marijuana leaf to create an extract if you wished to pursue documentation that her reaction is IgE-mediated. I could not, however, find any commercially available in vitro tests for Cannibis.

It is unknown whether a protective, daily administered pretreatment protocol would be helpful to her. If you did so, I would consider starting a non-sedating antihistamine along with montelukast on a daily basis, and supply her with an automatic epinephrine injector and an albuterol inhaler for as needed use. However, as you noted, the best therapy is clearly avoidance.

Thank you again for your inquiry and we hope this response is helpful to you.

West J Med 1983 (June); 183(6):829-831.
Allergic Skin Test Reactivity to Marijuana in the Southwest
Geraldine L. Freeman, MD
In a general allergy consultation practice in Arizona and western New Mexico, 129 patients were tested for immediate hypersensitivity skin test reactivity to marijuana pollen and tobacco leaf, as well as to a battery of other antigens. In all, 90 patients were diagnosed as allergic (atopic) and, of these, 63 (70 percent) were found to be skin test reactive to marijuana pollen and 18 (20 percent) to tobacco leaf. The incidence of skin test reactivity to marijuana was not significantly different for persons living at low, middle or high elevations throughout the Southwest. Marijuana sensitivity occurred in patients who were, in general, also sensitive to a variety of other airborne plant pollens. There was no close correlation, however, between sensitivity to marijuana pollen and sensitivity to pollens from elm, mulberry, hop and stinging nettle, which are botanically related to marijuana. The data suggest that marijuana pollen may be a relatively common airborne pollen pollutant in the Southwest, allergic persons being sensitized through inhalation. If this is confirmed by further studies, then clinical investigation of marijuana hyposensitization (immunotherapy) may be warranted. This is in contrast to tobacco allergy for which simple avoidance is recommended

The Journal of Allergy and Clinical Immunology
Volume 119, Issue 1, Supplement , Page S273, January 2007
Allergy to Marijuana: Case report
S. Perez-Bustamante, M. Vazquez de la torre, A. Villanueva
Rationale: Allergic reactions to marijuana (Cannabis sativa) is rare. Contact urticaria is the most common presentation. No cutaneous allergy has ever been reported following marijuana inhalation.
Methods: We described a 21-year-old man who referred, in the last two years, several episodes of papular lessions, itching and generalized erythema associated in some cases with palebral angioedema after smoking a considerable amount of marijuana. These episodes dissapeared in hours with antihistamines. He tolerated to smoke 2 cigarettes of marijuana without any symptoms.

An extract of marijuana leaves was prepared in phosphate buffer. Prick-prick was performed with marijuana leaves and extract. Serum specific marijuana IgE levels were measured by ELISA. The molecular mass of the IgE binding proteins was determinated by SDS-PAGE IgE-Inmunoblotting.

Results: Prick-prick test resulted positive to leaves and extract of marijuana. Specific IgE to marijuana was positive: absorbance OD490: 0,710 kU/L (control: 0.100). The apparent molecular weight of the allergens present in marijuana extract measured 69, 38, 26 and 10 kD. The patient reduced the number of marijuana cigarettes to two and since then he is asymptomatic.
Conclusions: We present a dose-dependent urticarial reaction to marijuana smoke exposure, in a nonatopic patient. Specific IgE mechanism is suggested by a positive prick test and IgE determination.

IgE-Mediated Hypersensitivity Reactions to Cannabis in Laboratory Personnel
T. Herzinger, P. Schöpf, B. Przybilla, F. Ruëff
International Archives of Allergy and Immunology, Vol. 156, No. 4, 2011
Background: There have been sporadic reports of hypersensitivity reactions to plants of the Cannabinaceae family (hemp and hops), but it has remained unclear whether these reactions are immunologic or nonimmunologic in nature.
Objective: We examined the IgE-binding and histamine-releasing properties of hashish and marijuana extracts by CAP-FEIA and a basophil histamine release test.
Methods: Two workers at a forensic laboratory suffered from nasal congestion, rhinitis, sneezing and asthmatic symptoms upon occupational contact with hashish or marijuana, which they had handled frequently for 25 and 16 years, respectively. Neither patient had a history of atopic disease. Serum was analyzed for specific IgE antibodies to hashish or marijuana extract by research prototype ImmunoCAP, and histamine release from basophils upon exposure to hashish or marijuana extracts was assessed. Results were matched to those of 4 nonatopic and 10 atopic control subjects with no known history of recreational or occupational exposure to marijuana or hashish.
Results: Patient 1 had specific IgE to both hashish and marijuana (CAP class 2), and patient 2 to marijuana only (CAP class 2). Controls proved negative for specific IgE except for 2 atopic individuals with CAP class 1 to marijuana and 1 other atopic individual with CAP class 1 to hashish. Stimulation of basophils with hashish or marijuana extracts elicited histamine release from basophils of both patients and 4 atopic control subjects.
Conclusions: Our results suggest an IgE-related pathomechanism for hypersensitivity reactions to marijuana or hashish.

Allergol Immunopathol (Madr). 2011 Sep;39(5):271-9. Epub 2011 Jan 26.
Allergic hypersensitivity to cannabis in patients with allergy and illicit drug users.
Armentia A, Castrodeza J, Ruiz-Muñoz P, Martínez-Quesada J, Postigo I, Herrero M, Gonzalez-Sagrado M, de Luis D, Martín-Armentia B, Guisantes JA.
Allergy Unit, Rio Hortega University Hospital, Valladolid, Spain.
Background: Cannabis is the illicit drug most widely used by young people in high-income countries. Allergy symptoms have only occasionally been reported as one of the adverse health effects of cannabis use.
Objectives: To study IgE-mediated response to cannabis in drug users, atopic patients, and healthy controls.
Methods: Asthmatic patients sensitised to pollen, and all patients sensitised to tobacco, tomato and latex, considered as cross-reacting allergens, were selected from a data base of 21,582 patients. Drug users attending a drug-rehabilitation clinic were also included. Controls were 200 non-atopic blood donors. Specific IgE determination, prick tests and specific challenge with cannabis extracts were performed in patients and controls.
Results: Overall, 340 patients, mean age 26.9±10.7 years, were included. Males (61.4%) were the most sensitised to cannabis (p<0.001). All cannabis-sensitised patients were alcohol users. Eighteen (72%) of the patients allergic to tomato were sensitised to cannabis, but a positive specific challenge to cannabis was highest in patients sensitised to tobacco (13/21, 61.9%), (p<0.001). Pollen allergy was not a risk factor for cannabis sensitisation. Prick tests and IgE for cannabis had a good sensitivity (92 and 88.1%, respectively) and specificity (87.1 and 96%) for cannabis sensitisation.
Conclusions: Cannabis may be an important allergen in young people. Patients previously sensitised to tobacco or tomato are at risk. Cannabis prick tests and IgE were useful in detecting sensitisation

Int Arch Allergy Immunol. 2008;146(3):195-202. Epub 2008 Feb 11.
Sensitization and allergy to Cannabis sativa leaves in a population of tomato (Lycopersicon esculentum)-sensitized patients.
de Larramendi CH, Carnés J, García-Abujeta JL, García-Endrino A, Muñoz-Palomino E, Huertas AJ, Fernández-Caldas E, Ferrer A.
Unidad de Alergia, Hospital Marina Baixa, Villajoyosa (Alicante) and Centro de Especialidades Foietes, Benidorm, Spain.
Background: Cases of allergy to Cannabis sativa have occasionally been reported, but both the allergenic profile and eventual cross-reactivity pattern remain unknown.
Objective: To analyze the allergenic profile of a population of patients from Spain sensitized to C. sativa and to characterize the C. sativa leaf extract.
Methods: A total of 32 subjects were enrolled in the study: group A, 10 individuals sensitized to tomato, reporting reactions by contact or inhalation to Cannabis; group B, 14 individuals sensitized to tomato, without reactions to Cannabis; group C, 8 individuals not sensitized to tomato and without reactions to Cannabis. Sensitivity to Cannabis, tomato and peach peel, Platanus hybrida and Artemisia vulgaris pollen extracts was measured by skin tests and specific IgE. Individual immunoblots and inhibition experiments with a pool of sera were conducted.
Results: All tomato-sensitized subjects (and 1 negative) had positive skin tests to C. sativa leaves and hashish. Specific IgE to C. sativa and peach peel was more common than to tomato. Immunoblot experiments showed 2 prominent bands of 10 and 14 kDa and 2 weakly recognized bands of 30 and 45 kDa. Tomato, peach and A. vulgaris extracts inhibited most of the bands present in C. sativa. P. hybrida inhibited only the high-molecular-weight bands.
Conclusion: Sensitization to C. sativa with or without symptoms is frequent among patients in Spain sensitized to tomato. C. sativa leaves are a potential allergenic source and their allergens may cross-react with other allergenic sources from plants (fruit peels and pollen).

Phil Lieberman, M.D.

Close-up of pine tree branches in Winter Close-up of pine tree branches in Winter