Eczemas - Allergic & Nonallergic

The diagnosis of eczematous skin conditions can be difficult for a number of reasons, including identification of a cause and when, where and how the causative factor is encountered. 

Occupational Skin Diseases
Occupational skin diseases are considered as a special class of dermatologic conditions for only one reason - they are caused by encounters with substances related to a person’s job or occupation. Otherwise, the skin diseases related to occupation are the same diseases acquired elsewhere. Diagnosis of an occupational skin disease may require some detective work by both patient and dermatologist - for example, associating when a skin condition first appeared and when it worsens to job activities and encounters with potential skin irritants or allergens. A skin condition associated with occupation may be worsened at home by encounters with other irritants such as strong soaps and detergents. 

The most frequent occupational eczema or eczema-like conditions are:

• Irritant contact dermatitis

• Allergic contact dermatitis

• Contact urticaria (hives)

• Skin infections

• Others, including "prickly heat" and acne
  

Irritant Contact Dermatitis
The majority of occupational skin disease is irritant contact dermatitis affecting the commonly exposed areas of skin on the hands, forearms, and face. Severity of the dermatitis ranges from red, chapped skin to blistering and skin ulcers. Itching is a common symptom that often promotes continuous, skin-damaging scratching.

Many factors may be involved in (1) the development of irritant contact dermatitis, (2) abrupt or slow onset of the condition, (3) severity of the condition, and (4) relative resistance to treatment. 

Atopy - a genetic predisposition to exaggerated responses to trigger factors - may be a significant factor in disease severity and resistance to treatment in atopic individuals. Environmental influences on disease can include heat, humidity, friction, and the nature of the irritant substance (solid, liquid or gas). 

The number of potential irritants is very large and on-the-job contact may be with one or more:

• Acids

• Adhesives and glues

• Alkalis

• Aromatic chemicals

• Bacteria

• Cement

• Chemical salts

• Ethylene oxide and other gases

• Foods

• Fungi

• Glass fibers

• Metals - silver, gold, arsenic, beryllium, mercury, and others

• Oils and greases

• Plants (stems, leaves and extracts)

• Sawdust

• Soaps and detergents

• Solvents

• Tar and asphalt
  

Whereas contact with high concentrations of these agents for prolonged time periods can cause eczema in most people, persons with atopy may react to brief contact with low concentrations of the agents.

These photos show typical presentations of occupational irritant contact dermatitis:


Irritant contact dermatitis due to glass fibers.



Irritant contact dermatitis in a taxidermist due to contact with adhesives used in the occupation.

(Photos used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

The most effective treatment for irritant contact dermatitis is identification and avoidance of the irritant substance. Modification of exposure, protection, and worker education are essential steps in clearing this form of occupational dermatitis. Skin symptoms, including itching, can be treated by a dermatologist. A person with occupational irritant contact dermatitis should avoid using strong soaps and detergents at home, and should follow a program of skin care recommended by a dermatologist.

Allergic Contact Dermatitis
Allergic contact dermatitis is discussed in detail in the second section of this Update. Allergic contact dermatitis (ACD) can pose a greater problem for the patient than irritant contact dermatitis. The allergen should be identified, substituted, or avoided and protected against by using appropriate gear, such as gloves or facemasks. Under these circumstances, most workers can continue in their jobs, only rarely, after careful evaluation may they need to change occupations. The list of potential occupational allergens is very long, and includes metals, organic and aromatic chemicals, plants and plant extracts.

Contact Urticaria
Contact urticaria (hives) can be allergic or nonallergic, combined allergic and nonallergic, and combined allergic eczematous and urticarial (eczema plus hives). It is difficult for a patient to recognize which allergic or nonallergic pathways are at work in an outbreak of hives. The red, raised, usually intensely itchy lesions called hives occur in the dermis (middle layer of skin under the epidermis). A more severe process called angioedema occurs in the dermis and subcutaneous tissue and can be life-threatening due to respiratory arrest and circulatory collapse.

Persons with atopic dermatitis may be more susceptible to allergic contact urticaria - for example, from contact with latex in rubber gloves used by healthcare workers. Contact urticaria should be evaluated by a dermatologist to identify the substances(s) causing the condition, and treated to reduce swelling and control itching.

Skin Infections
Persons who work in health care, veterinary medicine, agriculture and food processing may come into contact with infectious agents that cause skin conditions. Bacterial and fungal skin infections may resemble eczema, but the treatment is entirely different and the incorrect treatment may have serious consequences. Skin conditions that may be infections should be examined and treated promptly by a dermatologist.

Acne
Heavy industrial oils, greasy stage makeup, cosmetics, cooking oils and chlorinated chemicals may be comedogenic (causing blackheads and whiteheads that plug sebaceous follicles). Tight headgear (helmets, etc.), and gear straps (military gear, etc.) may be comedogenic in athletes, soldiers, etc. (Link to AcneNet for more information on causes and treatment of acne). 

Other Occupational Skin Conditions

• Frictional dermatitis is caused by handling of tools, heavy papers, fabrics, etc.

• Miliaria is a heat-related condition sometimes called "prickly heat".
  

Allergic Contact Dermatitis
Allergic contact dermatitis (ACD) is a common and often puzzling skin condition. The allergens involved are frequently of the type called haptens - simple chemicals that must bond with a protein to form a complete antigen (a molecule that can cause an immune response). Other allergens involved in ACD are more complex substances than haptens. A typical hapten-type allergen involved in ACD is nickel, as might be found in jewelry. ACD due to nickel allergy is shown in this photo:

(This and other photos in this discussion of ACD are used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides and the Sulzberger Institute for Dermatologic Education)

ACD due to more complex substances is shown in the next series of photos:


ACD due to allergic reaction to adhesives in a shoe.


ACD due to chemicals in shampoo.


ACD due to rubber.


ACD due to latex in hospital gloves.


ACD due to formaldehyde residue in new clothing fabric.


ACD due to a fragrance used on the skin.


ACD due to the topical antibacterial bacitracin.


ACD due to topical vitamin E cream.

Poison ivy is a frequent cause of allergic contact dermatitis.

It is not know if ACD is genetically related. Age is a factor - older adults' immunologic responses become dampened and they are less likely to have contact sensitization than younger persons.

The appearance of ACD can vary depending on its location and how long it persists. A common ACD eruption consists of inflamed, reddened areas on the skin, papules (solid elevated bumps on the skin), with or without blisters of greater or lesser size. There may be swelling under the skin (edema), flaking and cracking of skin. Typical areas of the body for ACD are:

• Face, ears and neck (cosmetics, skin and hair care products, jewelry and frequent causes);

• Hands (latex and rubber-based products, chemicals, leaves and stems of plants, etc.)

• Feet (rubber-based shoe liners, adhesives in shoes, dyes in socks, etc.)

• Systemic (ACD of a localized area becomes ACD of the entire body upon re-exposure to the allergen)
  

Treatment of ACD includes:

• Identification of the allergen by patch testing;

• Avoidance of the allergen;

• Substitution of the allergen;

• Treatment of dermatologic symptoms by a dermatologist may include - emollients for skin dryness, topically applied anti-pruritics and oral antihistamines for itching, steroids for anti-inflammation, corticosteroids used topically and systemically to reduce inflammation, and ultraviolet radiation to "down-regulate" immune responsiveness in the skin.
   

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