Occupational skin disease

American Family Physician,  Sept 15, 2002  by W.F. Peate

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Work-related skin diseases account for approximately 50 percent of occupational illnesses and are responsible for an estimated 25 percent of all lost workdays. These dermatoses are often underreported because their association with the workplace is not recognized. (1)

Occupational skin diseases affect workers of all ages in a wide variety of work settings. Industries in which workers are at highest risk include manufacturing, food production, construction, machine tool operation, printing, metal plating, leather work, engine service, and forestry. (2,3)

General Principles of Diagnosis

Because of the prevalence of occupational exposures that can cause or exacerbate skin disorders, it is advisable to screen all patients with skin disease for a work-related cause. If occupational skin disease is suspected, questions should be asked about the exact time relationship between the skin condition (i.e., onset, improvement, and recurrence) and the work exposure, including the effects of time off and return to work. An in-depth occupational history should cover the following points:

1. General work conditions (e.g., heat, humidity) and specific activities in the patient's present job that involve skin contact with potential hazards. Note that Material Safety Data Sheets are more informative for large acute exposures than for the low-level chronic exposures that are so common with skin conditions.

2. Physical, chemical, and biologic agents (chemical and trade names) to which the patient is or may be exposed.

3. Presence of skin diseases in fellow workers.

4. Control measures to minimize or prevent exposure in the workplace, including personal and occupational hygiene (e.g., handwashing instructions and facilities, showers, laundry service) and the availability of gloves, aprons, shields, and enclosures.

5. Compensation the patient received for skin disease in a previous job.

6. Other exposures, including soaps, detergents, household cleaning agents, materials used in hobbies (e.g., resins, paints, solvents), and topical medications, especially those containing sensitizing agents such as neomycin (e.g., Neosporin).

The depth of questioning should reflect the morphologic presentation of the skin disorder. The physician should look for eczema, hives, asthma, hay fever, clothing or food allergy, psoriasis, acne, oily skin, miliaria (i.e., "prickly heat," with many tiny vesicles near openings of sweat and sebaceous glands), contact allergies (e.g., reactions to metal objects, cosmetics, home cleansers), fungal infections (e.g., athlete's foot, ringworm), family history of atopy or psoriasis, and systematic diseases that may have skin manifestations (e.g., diabetes mellitus, peripheral vascular disease).

The history of the illness and the occupational history may reveal a close association between the skin condition and a specific work exposure known to produce such skin effects. The appearance of the condition may also suggest the cause. For example, a glove-pattern distribution of vesicular lesions on the hands strongly indicates a contact dermatitis.

It is not unusual to discover an underlying skin disease that is exacerbated by work exposures. However, multiple occupational and nonoccupational exposures may be identified, no clear time relationship between the skin lesions and the work history may be found, or the skin lesions may be difficult to classify.

General Principles of Treatment

For therapeutic purposes, contact dermatitis can be classified as acute (weepy, edematous, vesicular, blistered) or chronic (dry, cracked, scaly, thickened). Therapeutic measures can almost always provide some relief, but cure depends on identification of the offending agent and cessation of exposure.

ACUTE DERMATITIS

Wet Dressings. Absorbent material (e.g., cotton dressings) moistened with cool water or Burow's solution (aluminum acetate diluted 1:40 in water) should be applied to the affected area four to six times a day. The effects of this treatment include bacteriostasis, gentle debridement, debris removal, and evaporative cooling (which lessens pruritus).

Steroids. Topical steroids have no effect on acute vesicular reactions, but they may be applied once vesicles have resolved. Systematic steroid therapy is indicated when lesions are widespread, vesicular, and edematous or bullous. Short courses of prednisone, in a dosage of 40 to 60 mg per day for five to seven days, are usually satisfactory and do not require tapering. Secondary infections should be treated. Systemic steroids should be used cautiously in patients with diabetes mellitus, psychotic disorders, uncontrolled hypertension, or infections such as tuberculosis or herpes.

Systemic Antihistamines. Diphenhydramine (e.g., Benadryl), in a dosage of 25 to 50 mg three or four times daily, or hydroxyzine hydrochloride (Atarax), in a dosage of 25 mg three or four times daily, provides an antipruritic effect. Because of the sedating effects of these drugs, patients should be advised against operating machinery or vehicles. Doxepin (Sinequan), in a dosage of one to three 10-mg capsules taken at night as needed, is effective, but patients should be monitored for anticholinergic effects. A 5 percent doxepin cream (Zonalon) is also effective. Topical antihistamines should be avoided because of their potential sensitizing action.