CASE REPORT

Forty-year-old female, Caucasian patient, biologist, born and resident in São Paulo, SP. Four years before she came to the dermatology unit with hand eczematous dermatitis, when she was submitted to epicutaneous tests, which proved to be negative. The diagnosis of contact dermatitis by primary hand irritation was made, treated with topical corticosteroids and emollients, in addition to the recommendation of wearing gloves with fabric lining.

She came back to the outpatient center four years later complaining of pruritus and erythema on the back of the hands, present for two weeks. She reported that three months before she had had dyspnea after putting on latex gloves and required emergency care, medicated for bronchospasm.

The clinical history also revealed complaint of vulvar discharge after contact with condom and gynecological examination, in addition to lip edema when blowing up party balloons.

Dermatological examination showed the presence of eczematous dermatitis on the back of both hands, without palmar impairment.

We made the diagnostic hypothesis of allergic contact dermatitis, associated with contact urticaria, and the patient was submitted to new contact tests.

The contact test was performed using the Brazilian standard battery of tests (FDA – Allergenic/RJ – Brazil), including readings after 48 and 96 hours. The test showed positive response for thiuram (Figure 1). It also showed immediate reaction to rubber in the open test using glove fragment (Figure 2). Serum specific IgE dosage for latex (RAST –Radioallergosorbent test) was increased (14 KU/l), given that values over 3.5 KU/l are considered relevant for latex allergy.

Based on such data, the diagnosis of contact urticaria to latex (associated with respiratory symptoms) and contact allergic dermatitis to thiuram group was confirmed.

The exchange of gloves and instructions to avoid possible contact with latex sufficed to maintain the disease under control.

DISCUSSION

Natural latex is an emulsion derived from a tree, Hevea brasiliensis, popularly known as rubber tree. The emulsion comprises a complex intracellular product (cis-1,4 polyisoprene) and a series of proteins, many of them characterized as allergens (Hev b1 to Hev b11). Rubber manufacturing process includes addition of chemicals, such as carbamates and thiurams, which convey the characteristics of elasticity and longevity.

Rubber in the form of gloves can cause different types of reactions in subjects that wear them, such as contact dermatitis by primary irritation, contact allergic dermatitis to chemical additives and contact urticaria. The latter, associated with respiratory symptoms, is triggered by contact with natural latex proteins, through solution of continuity of skin, respiratory system or mucosa.

As of 1980, the need to protect against infectious-contagious diseases requires the use of latex gloves as mandatory and constant among healthcare professionals, which has brought about a new occupational risk - contact urticaria.

The frequency of latex reactions in developed countries has increased, taking to the creation of a series of recommendations and preventive measures. Some of them, such as the creation of study committees about latex, special surgical centers and alternative material artifacts, resulted in later decrease in number of severe reactions ^{1, 2, 3}. The prevalence of sensitivity to latex in the general population is 1%, but among healthcare professionals it ranges from 3% to 14% ¹. The main source of reactions to latex is related to contact with gloves, and frequency of exposure is more important than duration to induce sensitivity ^{4, 5, 6}.

Glove talc acts as carrier of latex proteins taking them into the respiratory system, thus, people occupationally exposed to rubber gloves with talc have increased risk of developing rhinoconjunctivitis and asthma . Latex proteins are absorbed slowly after air exposure and the symptoms develop approximately 30 minutes after contact. Powdered gloves release particles with latex protein capable of triggering respiratory symptoms through IgE mediated mechanisms. ⁷

Despite the relative frequency of these cases among healthcare professions, this is the first case observed by the authors, after confirming the presence of two entities in the same subject.

There are some risk factors for the development of latex allergy, such as for example: being a healthcare professional and rubber industry worker; subjects submitted to multiple surgeries to correct congenital anomalies; frequent mucosa exposure (dental procedures, use of urine collectors or tubes); presence of allergic and irritating contact dermatitis, in addition to atopy .

There are foods that can trigger a cross-reaction with latex, such as for example banana, kiwi, papaya, peach and peanuts – it happens due to the presence of proteins similar to those in latex ⁸.

In the described case, the patient had as risk factors her professional activity, presence of primary irritation by contact dermatitis, and later, contact allergic dermatitis caused by rubber additives. The latter is characterized by the presence of eczematous dermatitis on the back of her hands, fingers, wrists and forearms ⁹. Thiuram group is the main sensitizer present in rubber gloves, used for hospital, home and industrial applications ^{10, 11, 12}.

The association between contact allergic dermatitis and contact urticaria in the same subject is a difficult to diagnose and infrequent event, but some literature reports showed this association, especially among healthcare professionals. In one of such studies, among 55 hospital workers, there were 33 (61%) with primary irritant contact dermatitis, 17 (31%) with contact allergic dermatitis (CAD) and 14 (27%) with contact urticaria (CU). In that group, six workers (11%) had both rubber CAD and latex CU, concomitantly ¹⁰.

Some measures adopted by manufacturers have contributed to reducing the number of both reactions. Concerning contact urticaria, gloves manufactured with fewer proteins, talc-free gloves and the use of other materials such as vinyl, nitril, chloroprene or tactylon, would contribute to reducing the sensitization rates ¹. Recently, some observations made about thiuram sensitization showed signs of decrease in Denmark, where recommendations made by European committees were adopted by glove manufacturers, replacing this agent by carbamate (dibutyldithiocarbamate), with lower sensitizing effect ¹³.

The present case report showed the diagnostic difficulty of the association of those two entities.

REFERENCES