Hydration of the skin is necessary for maintaining a healthy barrier, which is resistant to external influences. Dehydration of the skin may occur consequent to many agents but most important of these is the contact with soap and water – especially if the water is hot. Nowadays, seafarers will normally soap and wash in a hot shower before going to work and again after the work. Consequently, the loss of lipids and water results in the skin becoming dry, especially in wintertime when the indoor air-humidity is low. The use of soap should be limited and mild products used. Cool water should be preferred to hot. Atopic subjects are particularly prone to dry skin and the presence of skin dryness may predispose to irritative dermatitis. A moisturizing cream will restore the skin in most cases. If the dryness is severe, rehydrating can best be achieved by applying a urea-containing cream.
Contact dermatitis, urticaria
Contact dermatitis is a non-contagious inflammation of the skin, characterized chiefly by redness, itching, and the outbreak of lesions that may discharge serous matter (acute dermatitis) and eventually become encrusted and scaly (chronic dermatitis). It represents a tissue reaction that is characteristic to many skin disorders. The term eczema may be used as a synonym for contact dermatitis as well as for atopic dermatitis. In the current context dermatitis and eczema have identical meanings.
Contact dermatitis is a large group of skin diseases that may be work-related and/or interfere with work. They may occur consequent to skin exposure to allergenic substances, or – in particular – skin contact with irritating or corrosive factors, or a combination of the two. Various types of contact dermatitis are also frequent among seafarers.
Due to the rather stereotypical character of skin reactions, allergic and irritative (also known as toxic) contact dermatitis tend to look alike. Consequently, it is not always easy to distinguish the two types of contact dermatitis. Both are itchy and both can be viewed in an acute phase with redness and frequently vesicle formation and oozing (Figure 2-3), and in a chronic phase characterized by hyperkeratosis and the development of fissures (Figure 4).
Figure 2. Acute contact dermatitis.
Figure 3. Acute contact dermatitis.
Figure 4. Chronic hand dermatitis.
Minor differences between the two types of contact dermatitis may at times be of assistance at assessment. Irritative contact dermatitis can only occur where there has been an irritant exposure. Conversely, an allergic reaction may also be located beyond the contact area. Work-related contact dermatitis is mainly localized on the hands, since the hands would be the prime contact with the causative agent in most work situations. However, hands contaminated by irritants or allergens may also spread the agent to other skin areas, typically by touching the face. In addition, facial contact dermatitis can be caused by splashes of work materials or from an airborne agent such as gas, vapour or a solid/liquid aerosol (dust or droplets).
The generally accepted gold standard for an allergic contact dermatitis is the detection by patch test of a type IV allergic reaction (Figure 5). By extension, an allergic contact dermatitis tends to be excluded and to be interpreted as toxic if the patient’s skin does not respond to patch tests. But there are several sources of error. It is not possible to examine for an infinite number of potential allergens. Typically, the standard patch test includes approximately 20 allergens, but may be extended by selecting additional substances of relevance to which the patient may have been exposed. But even then an allergy may not be recognized, for example because the relevant substance is not identified among exposures and therefore is not tested for. In addition, a positive reaction to the patch test needs not to be due to an allergic reaction. Despite dilution, patch testing with many substances will almost inevitably lead to an irritative reaction that may be misinterpreted as allergic. Furthermore, a demonstrated allergy does not necessarily represent the cause of the dermatitis. A subject who is already allergic to nickel, for instance, can obviously contract an allergy to a new substance that may not have been tested for, and will also not necessarily be protected from irritative reactions. Finally, with very potent allergens the testing procedure itself may result in sensitization. Therefore, following patch testing one can speculate whether a positive reaction was is in fact due to a previous exposure to the allergen, or whether the diagnostic investigation itself has resulted in sensitization. A positive reaction, therefore, does neither necessarily mean that the dermatitis was of an allergic nature and caused by a specific substance nor does a negative reaction justify the conclusion that the dermatitis was irritative.
Figure 5. Patch test.
It is not normally a task for the occupational or maritime physician to perform patch testing, but rather to provide information on the exposures of potential relevance and to suggest the relevant contents of the test to the involved dermatologist. Therefore, the exposure story is important, and the practitioner in maritime medicine should recognize the potentially harmful exposures in the maritime setting in general and specific exposures that relate to certain tasks in particular.
At times, toxic and allergic dermatitis may co-exist. For example a machinist may develop allergic sensitisation to an additive in a mineral oil product that has already caused irritant dermatitis. In the absence of knowledge about the exposures and their relevance one cannot plan patch testing or assess the significance of any positive and negative outcomes of patch testing.
To conclude, confirmation of a case of a dermatitis as irritative demands not only that an allergic component has been excluded but also that an irritative exposure has been demonstrated.
Urticaria (hives) is a rash with characteristic pale red, raised, itchy elevated areas of the skin (wheals). This reaction is related to angioedema, which occasionally – when located in the mouth or pharynx - may be a medical emergency. Hives may have allergic or non-allergic causes. Acute urticaria lasting less than six weeks is usually the result of an allergic trigger. Acute viral infection is common cause of acute urticaria. Chronic urticaria lasting longer than six weeks is rarely allergic. Most chronic urticaria is idiopathic and may have an autoimmune cause.
Urticaria (Figure 7) may also be allergic or non-allergic. Allergic contact urticaria (Type 1 allergy) may be related to contact with or ingestion of certain – in particular organic – substances such as a variety of foods including fish (Figure 8). Allergic contact urticaria may also be caused by toxins, e.g. from insect bites or infections. Type 1 allergy may be demonstrated by prick tests or by measurement of specific Ig E in serum.
Non-allergic urticaria may have many causes: Cholinergic urticaria is common after exercise, sweating, or any activity that leads to a warming of the core body temperature such as warm or hot baths or showers. Dermatographic urticaria (dermatographism or "skin writing") is very common and marked by the appearance of weals or welts on the skin as a result of scratching or firm stroking of the skin. Temperature extremes may cause heat and cold urticaria, and sunlight and water exposure may also cause urticaria. Exercise urticaria is a condition with hives, itchiness, shortage of breath and low blood pressure 5 to 30 minutes after the inception of exercise. These symptoms can progress to exercise-induced anaphylaxis, shock and even sudden death.
In practice, it is often difficult to identify the causal mechanisms for allergic as well as non-allergic urticaria, and it is also difficult to distinguish between them. Antihistamines usually provide rapid relief but, depending on its location, angioedema may demand more aggressive treatment with steroids and adrenaline.
Protein contact dermatitis refers to an allergic skin reaction caused by contact with proteinaceous material. An acute urticarial or vesicular eruption develops minutes after contact with one of four groups of the causative protein: plant, animal, flour, and proteolytic enzymes. Immediate prick- or scratch test results are usually positive while patch tests are often negative. Anecdotally, risk factors for the development of protein contact dermatitis include a history of atopy, chronic irritant dermatitis, and an exposure to one of these protein allergens. Treatment involves avoidance of the particular allergen and symptomatic relief may be provided with short-term corticosteroids, immune-modulatory agents, or antihistamines.
Examples of irritative exposures in the maritime setting include detergents in the galley, lubricants and cooling fluids in the engine room, transported chemicals and oil products, drilling mud on oil or gass platforms, and other substances that can affect and destroy the properties of the keratin layer of the skin. Interestingly, repetitive and prolonged exposure to water can also frequently contribute to dry and irritated skin. On fishing vessels, contact with fish may in itself cause dermatitis. The skin-irritating properties of fish increases with the post-mortem age of the fish.9 This property may constitute a problem for fishermen, in particular when handling fish for fishmeal production. Other irritative effects may be thermal, actinic or physical, e.g. persistent friction on the skin. Dry irritated skin may also be induced by exposure to chemicals in powder form.
Many allergic reactions have been reported in seafarers and fishermen.8 While most of these are the same as allergic contact dermatitis or contact urticaria seen in other occupations with similar exposures, a few are characteristic to the maritime population – especially the fishermen. Dogger Bank itch reported from fishermen in European waters is a disabling allergic contact dermatitis that is occasionally associated with photosensitivity and is caused by a metabolite produced by species of a marine Bryozoa (Figure 6).10-12 While steroids seem to be frequently unable to control the condition, cyclosporine has been reported as effective.13 Several reports have described allergic reactions to cuttlefish in fishermen.14,15 An extensive literature study reported occupational protein contact dermatitis in workers exposed to various types of seafood (crustaceans, molluscs, bony fish, etc,) in 3% to 11% of the exposed workers. Only few of these studies, however, dealt with fishermen. Disruption of the intact skin barrier seems to be an important added risk factor.16 Fishermen may develop urticarial reactions to anisakis (a parasitic nematode in fish)17 and protein contact dermatitis following the use of maggots of a flesh fly as bait.18
In offshore oil and gas exploitation, exposure to drilling mud may cause irritant dermatitis. Drilling mud is a complex oil- or water-based mixture that is recirculated via mud tanks and serves to remove rock cuttings, to cool and lubricate the bit, and to maintain a pressure in the hole to prevent influx of gas and crude oil. The composition of drilling mud has changed over time and is now much less toxic than previously.19 In addition to irritant contact dermatitis, exposure to drilling mud has been reported to cause sensitization to polyamide (diethylenetriamine, triethylenetetramine),20 white spirit and alpha olefin21 in offshore workers.
Figure 6. Dogger Bank itch.
Figure 7. Urticaria.
Figure 8. Allergic contact urticaria caused by exposure to fish.
Atopy is a hereditary condition with constitutional dry skin, which is particularly common in children and young people and frequently accompanied by airway allergy. The skin of atopic subjects is less resistant to external exposures and particularly prone to irritative contact dermatitis. In turn, atopic subjects have a slightly less risk of allergic contact dermatitis. But as the presence of an irritant contact dermatitis will increase the possibilities for allergenic substances to penetrate the skin, both types of dermatitis may be present simultaneously.
In atopic children and in youth, atopic dermatitis frequently manifests in the flexures such as the knees and elbows (Figure 9), while hand dermatitis is the main problem in adult atopics. Atopic seafarers and fishermen are prone to develop irritative dermatitis with exposure to water, detergents, solvents etc. in addition to an increased risk of allergic contact urticaria to proteins such as latex from gloves and various foodstuffs.
Figure 9. Flexural atopic dermatitis.
There is some evidence that the prognosis of skin disorders in young atopic subjects may be influenced by advice with regard to their future occupation. However, this type of pre-placement advice is currently not systematically implemented.
Treatment. Patients with contact dermatitis should be treated effectively. Topical steroids are indicated whether the dermatitis is irritative or allergic. They come in different strengths and may have considerable side effects. Cream is suitable for most conditions but ointment may be better with a chronic dermatitis accompanied by extreme dryness. There is a tendency among the public to be needlessly worried about the administration of topical steroid hormone because of the recognized side effects of these preparations. Patients with dermatitis should, however, understand that the adverse consequences of refraining from treatment might well exceed those of treatment. The potency of local steroid treatment should not be larger than necessary, but on the other hand sufficient for achieving quick recovery. Normally, one would require steroids of intermediate potency for topical application. In the face, however, only mild steroid such as hydrocortisone should be used. The intensive treatment should be continued for a few weeks after the dermatitis has disappeared, then the application intervals can be gradually decreased. It should be recognized that the skin remains vulnerable for several months after the dermatitis has subsided even though the skin looks completely normal. During this time, it is essential that the skin’s moisture and lipid content is kept intact by continuous treatment with a humidifying cream. Therefore, care and prevention of relapse require patience and persisting care on all fronts, both when working on board and when at home ashore.
Obviously, it is important to reduce (for irritation) or eliminate (for allergies) the stimuli that triggered the dermatitis. Should this be a harmful exposure at work, the implication is not necessarily that the seafarer should be removed from the workplace or from the triggering task. A harmful technology may be substituted with a less harmful process or product, e.g. epoxy paint may be replaced by another type of paint, or an offending food product may be replaced in the galley. Frequently, less aggressive hand cleansing and the introduction of regular skin care with a humidifying agent may suffice.
Skin protection. A common and appropriate means of primary as well as secondary prevention will be to protect the skin by the use of gloves that should be suitable for the particular work. Issues to consider include cut resistance, penetration characteristics, and grip. Gloves should be kept intact and clean, and particular emphasis should be given to their inside. Similar to other personal protective equipment, the use of gloves should always be subsidiary to other preventive actions. Gloves can be unpleasant to use and may at times in themselves pose a security risk or cause skin disease. On the other hand, in spite of the acknowledged side effects of protective gloves much work on board does require their use as a primary preventive means – not least as protection to cuts and other injuries.
Allergic hand dermatitis from the use of gloves may be due to sensitization from chrome, used for tanning leather gloves, or to additives in the rubber used for gloves – e.g. mercaptobenzothiazole.22 A type 1 response with sensitization to latex, which is present in rubber gloves, is a common cause of contact urticaria. In addition, merely the occlusion of the skin by the use of gloves for several hours may harm the skin. In subjects with a tendency to hyperhidrosis or dyshydrosis, these conditions may worsen considerably by the wearing of gloves. Inner cotton gloves may reduce this problem and should be used in most situations where gloves are needed. Inner cotton gloves should be regularly washed or replaced.
Ideally, gloves should last long enough for the work to be done taking into account the exposure. The reality is, however, that gloves will eventually be degraded and sooner or later penetrated, and consequently that the protection by gloves may well be a relative one. Sometimes, cheap disposable gloves that are changed regularly may be preferred to gloves that are used for a longer time. At sea, however, most tasks that require the protection of the hands, necessitates the use of gloves meant for heavy duty. The manufacturer should be able to provide information about the quality and resistance to various agents, so that the right gloves can be selected and then changed well before penetration. Information may also be found on the Internet.
When gloves are not suitable for the work, protective “barrier” creams that are suitable for the exposure may provide some protection of the skin23 but should not be used for preventing penetration of an agent through the skin. It is important to know that some types are suitable for oils and solvents and others for water and detergents. Good general hand hygiene should be promoted, and an appropriate moisturizer should be available for dry skin.
Other types of dermatitis
Seborrhoeic dermatitis is caused by seborrhea, a common but mostly harmless pathologic overproduction of sebum. Subsequent infection and inflammation may lead to dry or greasy peeling of the scalp (often related to dandruff), eyebrows, and face, and sometimes trunk (Figure 10). The condition is related to presence of the widely present yeast Malassezia furfur as well as to genetic, environmental, hormonal, and immunological states. It may be aggravated by factors such as poor general health, psychological stress, fatigue, and change of season. Consequently, a flare-up may well occur at sea. A practical approach to treatment may be combinations of an anti-dandruff shampoo, an antifungal agent and a topical steroid.
Figure 10. Seborrhoic dermatitis.
Stasis eczema (gravitational) resulting from insufficient venous return from the legs is mostly associated with varicose veins (Figure 11). Compressive stockings or elastic dressing may prevent the stasis, and topical steroid will reduce the dermatitis. Ulcers may complicate the condition. Most important in these conditions is to avoid oedema by the use of compression (stockings or compressive bandage) and to combat bacterial infection.
Figure 11. Stasis eczema.
Psoriasis is a common chronic and frequently hereditary chronic skin disease caused by an excessively rapid growth of keratocytes. The disease usually presents with red, scaly patches that can be present at all locations but most commonly on the knees and elbows. Psoriatic plaques may be frequently located on in the scalp, on the palms of hands and the soles, or on the genitals (Figure 12). The affection of finger- and toenails may be mistaken for a fungal infestation (Figure 13). The disease may be recurrent or persistent. Persons with psoriasis are more likely to miss work for health-related reasons and their productivity and functional level is impaired.24,25 Seafarers are likely to be in the same magnitude of risk as other workers. Symptoms can be controlled by topical steroid, and UV light and salty water is beneficial.
Figure 12. Psoriatic plaques on elbows.
Figure 13. Nail affection in psoriasis
In up to 30% of patients, psoriasis is complicated by an inflammation in joints, and in particular axially along the spine and pelvic joints (Psoriatic arthritis). This complication may be serious and debilitating and requires specialist treatment by rheumatologists.
The so-called Köbner phenomenon is a cutaneous response seen in certain dermatoses such as psoriasis. It is manifested by the appearance on uninvolved skin of lesions typical of the skin disease at the site of trauma, on scars, or at points where clothing produces pressure. Workers with psoriasis frequently have psoriatric responses to an irritant or other noxious exposure that particularly involve the hands.
Figure 14. Köbner phenomenon in a patient with psoriasis.
Acne vulgaris (commonly called acne) is a common skin disease, characterized by areas of skin with multiple non-inflammatory follicular papules or comedones and by inflammatory papules, pustules, and nodules in its more severe forms. Acne vulgaris mostly affects the areas of skin with the densest population of sebaceous follicles such as the face, the upper part of the chest, and the back (Figure 15). Severe acne may be inflammatory. Acne lesions are caused by androgen stimulation in the pilosebaceous units.
Figure 15. Acne.
Acne affects more than 96% of teenagers, but often continues into adulthood. In adolescence, acne is usually caused by an increase in male sex hormones, which both genders accrue during puberty. Acne mostly diminishes over time and tends to disappear or decrease in the early twenties. Some individuals will carry this condition well into their thirties, forties and beyond.
The treatments for acne aim to normalize shedding into the pore to prevent blockage, to kill Propionibacterium acnei, to reduce inflammation, and to provide hormonal manipulation.
Treatments include benzoyl peroxide, antibiotics, retinoids, antiseborrhoic medications, salicylic acid, alpha-hydroxy acid, azelaic acid, nicotinamide, and keratolytic soaps. It should be noted that adverse ocular side effects to isotretionin include impaired vision and night adaptation. Reversible decreased colour vision is a probable side effect.26 These side effects may be an issue with watch-keeping.
Bullae and blisters
Bullae are fluid containing blisters larger than 5 mm in diameter (Figure 16). Bullous skin diseases may arise as autoimmune phenomena or due to external influence, e.g. second degree burns. Smaller blisters may form when the skin has been damaged by friction or rubbing, heat, cold or chemical exposure, but may also be due to infections such as herpes or varicella (Figure 17). So-called id-reactions proved by blistering may commonly accompany fungal infections such as tinea pedis or other dermatophyte. Fluid collecting between the epidermis and the layers below cushions the tissue underneath, protecs it from further damage and allows it to heal. Some blisters accompany infections and may be contagious.
Figure 16. Bullae.
Figure 17. Blisters in varicella.