An airborne dermatitis is characterised by the occurrence of the dermatitis on areas exposed to the air, which often makes it difficult to differentiate from a photodermatitis, and often by symmetry (e

AIRBORNE DERMATOSIS

Prof. An Goossens

Department of Dermatology (Contact Allergy Unit)

University Hospital

Katholieke Universiteit Leuven

Belgium

Introduction

Acute and chronic dermatoses of the exposed parts of the body and especially the face are sometimes caused by substances that are first released into the atmosphere and then settle on the exposed skin. This can occur in both professional and non-professional contexts. Such allergens may be present in the air as vapours, gasses, droplets, or solid particles (1-5).

1. The skin symptoms

The skin reactions caused by an airborne agent are multiple (1-4): airborne irritant and allergic contact dermatitis, phototoxic and photo-allergic reactions, (photo) contact urticaria, acne, exfoliated dermatitis, fixed drug eruption, hyper- and depigmentation, lichenoid eruptions, lymphomatoid contact dermatitis, paraestesia, pellagra-like dermatitis, purpura, pustular reactions, telangiectases, and erythema multiforme-like eruptions. A particular product can also cause several different reactions. In this article, we are primarily concerned with allergic reactions to airborne agents.

2. The nature of the airborne contactants

The harmful substances can occur in both professional and non-professional contexts, and the ways they enter the environment can vary considerably: vapours (volatile substances), droplets, or solid particles (1).

3. The location of the lesions

The most common sites for contact dermatitis caused by an airborne agent are the parts of the body that are directly exposed to the air: the face, neck, upper part of the chest, hands, wrists, and underarms.

Differentiating an airborne dermatitis from a photo-dermatitis may pose problems. However, allergic reactions on the following sites strongly suggest an airborne dermatitis as opposed to a photo-dermatosis (even though the latter may extend to shadowed areas):

· covered parts of the body, such as the major body folds, the genital region, but also the lower legs in men, as materials may be trapped under clothing;

· anatomically shadowed portions of the body:

- the eyelids

- the area behind the ears

- the scalp that is covered by hair

- the area under the chin.

The upper eyelids are particularly susceptible to airborne allergens and irritants and sometimes they are the only sites affected, and conjunctivitis may also occur. Occasionally, the lesions may take a more generalized form (1).

4. Diagnosis and differential diagnosis

Airborne allergens or irritants are suggested if the symptomatic complaints occur on particular parts of the body as mentioned previously, and when the symptoms clear when the patient changes environments. Patch testing should be performed with the suspected chemicals. Light tests and photo-patch tests can be useful for excluding a light factor in the pathogenesis of the lesions. The situation is, of course, more difficult for airborne irritants.

The differential diagnoses of airborne contact dermatitis must include contact allergic reactions caused by directly applied agents, by occasional contacts with allergens, by transfer of the allergens (“ectopic”) dermatitis, connubial or consort dermatitis, an id-like spread of a dermatitis elsewhere on the body, systemic eczematous contact dermatitis-type reactions, and photo-induced dermatosis. Other eczematous skin conditions, particularly atopic dermatitis, but also seborrheic dermatitis must be considered.

5. The airborne irritants and allergens

The nature of the airborne allergens vary and may concern:

· vegetable and wood allergens

· plastics, rubber and glues

· metals

· industrial, household, laboratory and pharmaceutical chemicals

· agricultural chemicals (insecticides, pesticides, animal feed additives)

· cosmetics

· solvents

Extensive lists of causal agents have been published in the literature (1-5).

6. Conclusion

Dermatologists and occupational physicians ( occupationally-induced reactions are still by far the most common!) have to deal more often with airborne allergens and irritants than the literature would seem to indicate, but the awareness has grown over the years (3, 4). Airborne irritants are certainly more common than allergic reactions, although they are more difficult to demonstrate.

Recognizing the characteristic nature of the reactions can greatly facilitate the diagnosis. Such reactions could be strongly suspected when symmetric lesions occur on the exposed body parts (sometimes even on occluded areas!), and especially the eyes and the face in general, when the patient denies having applied any topical agents and when the symptoms clear when the patient changes environments.

References

1. Dooms-Goossens AE, Debusschere KM, Gevers DM, Dupré KM, Degreef H, Loncke JP, Snauwaert JE. Contact dermatitis caused by airborne agents. J Am Acad Dermatol 1986; 15: 1-10.

2. Lachapelle JM. Industrial airborne irritant or allergic contact dermatitis. Contact Dermatitis 1986; 14: 137-145.

3. Dooms-Goossens A, Deleu H. Airborne contact dermatitis: an update. Contact Dermatitis 1991; 25: 211-217.

4. Huygens S, Goossens A. An update on airborne contact dermatitis. Contact Dermatitis 2001; 44: 1-6.

5. Goossens A, Huygens S. Dermatosos aerotransportadas profesionales. In: Dermatología profesional. Eds. Conde-Salazar Gómez L, Ancona-Alayón A. Grupo Aula Médica, Madrid, 2004, pp. 289-300.