Dermatitis

Occupational dermatitis is a non-infectious inflammatory condition of the skin which results from external contact with chemical, biological or physical agents. It is a prescribed disease under the Social Security Act 1975, with the exception of dermatitic conditions caused by ionising particulate or electromagnetic radiation. The condition may in some cases cause only minor inconvenience. Occupational dermatitis is a reportable disease as part of RIDDOR .

The skin provides the body’s main defence against external irritants, providing a oily protective covering, it has the outer world on one side and the body on the other.

Organic solvents are able to dissolve away the greasy secretion on the skin so the natural protective mechanism is reduced (de-fatting). Any breaks or reduction in the thickness of the outer layer caused by friction, heat or excessive sweating, will also reduce resistance to attack from external irritants. The openings to the hair follicles and sebaceous glands provide another means of access for irritants to enter the skin structure, especially for fat soluble substances.

Estimates of the prevalence of occupational dermatitis in Great Britain – meaning the total number of people ill at any given time – may be derived from the Self-reported Work-related Illness (SWI) module of questions included annually in the national Labour Force Survey (LFS). Latest results estimated that in 2009/ 10, 22 000 people who worked in the last 12 months suffered had “skin problems” caused or made worse by work.

Forms of Dermatitis

Contact (irritant) dermatitis is a condition brought about by contact with substances (or conditions) called primary (cutaneous) irritants. Dermatitis occurs at the site of contact provided the irritants act for a sufficient time and in sufficient concentration. Direct attack on the outer layers of the skin causes tissue destruction and/or degreasing, allowing absorption into the “active” areas of the skin, where inflammatory conditions develop.

Irritants include:-
Greases
Mineral oils
Solvents, e.g. white spirit
Acetone
Strong alkali and acids
Cement
Physical agents: heat, cold, radiation, friction

An important point to note about dermatitis is that after removal of the operative from contact with the irritant, recovery generally occurs. Further exposure to the irritant can be tolerated provided extra precautions are taken to limit contact and exposure.

Contact dermatitis develops on the body where contact occurs. Main body areas are the hands, arms, face and neck.

Allergic dermatitis is caused by substances called cutaneous sensitisers. These substances do not always cause an inflammatory response on first contact but may take a week or more to develop. A more serious condition, immune (allergic) response, occurs in the metabolic reactions of the skin structure and develops within hours of contact with the sensitising material.

Sensitisers include:-
Rubber additives & latex
Nickel compounds
Hair dyes
Methanol solutions (formalin)
Wood dust: e.g. African teak
Resins used in plastic manufacture

Recovery from the dermatitic condition occurs when contact with the offending material is removed. However, in complete contrast to contact dermatitis, the sensitisation remains so that further contact with the substance evokes a severe dermatitic and immunological response. Only a small concentration of the substance is required to cause the recurring attack. In the chemical industry, operatives who have suffered this condition can react simply by being “down wind” from the particular plant where the material is being manufactured. Recurrent immune responses cause dermatitis to occur in areas of the body other than where the initial condition developed.

The immune reaction may cause symptoms such as massive swelling around the eyes and face, on the hands, arms and ankles. i.e. latex, rubber, flour dust, wood dust.

The consequences of contracting sensitisation dermatitis are obvious: the person must be removed from any contact with the offending material.

Many modern chemicals are able to evoke both irritant and sensitising responses. Compounds of chromium and arsenic can cause dermatitis which may progress further to give ulceration of the affected areas.

Mineral oils may cause dermatitis and something far more serious, namely cancer of the scrotum. This occurs mainly in workers who are exposed to mineral oils which, by the nature of the process they operate, cause their clothes to become heavily contaminated over the thigh region. Typically, mechanics who keep an oily rag in their pocket would be likely candidates for this type of cancer.

Wart-like lumps are produced which develop into painful sores; if the condition is allowed to develop the lesion will spread and cause objectionable odours from the decaying flesh around the ulcerated condition.

Without medical intervention. tumours will spread to the testicle and into the abdomen. For many. the condition has been fatal. During the time leading up to death. considerable weight loss and pain can occur.

If early diagnosis of the condition is made, then, as with other skin cancers, recovery from the condition becomes possible. Better still, the condition can be avoided if sufficient care is taken to “design out” conditions that allow a worker to become saturated with oil. When there is a possibility of oil contamination of the genital area, the workers must be made fully aware of the potential risk, and be provided with special personal hygiene facilities, i.e. regular use of clean working clothes and underwear, with special washing facilities.