• If possible, identify the stimulus by taking a detailed history and examination, including:
• Occupational, recreational, and medical history, including family history of atopic dermatitis.
• The anatomical distribution of the rash.
• The amount of contact with the irritant or allergen.
• History of exposure to irritants, for example wet work or friction.
• Duration of contact.
• Time from contact to first presentation.
• Evolution of symptoms, for example one episode or recurrent episodes; does the skin clear completely between episodes?
• Establish whether the pattern of distribution of the dermatitis suggests contact with a particular allergen or irritant.
• Consider referral to a recognized centre for patch testing to exclude allergic dermatitis.
• Assess for any indication of secondary infection, for example rapid worsening of dermatitis, tenderness, increased erythema, heat, or discharge.

In depth

• Advise the person to avoid contact with the stimulus.
• Apply an emollient first-line to cool the skin and restore the skin barrier.
• Treat localized acute dermatitis with a topical corticosteroid.
• Prescribe a potency appropriate to the severity and location of the dermatitis (see Prescribing topical corticosteroids).
• Consider a systemic corticosteroid if there is significant impairment of function, such as in eczema on the hands.
• Consider treating extensive acute dermatitis (> 20% of total skin surface involved) with a systemic corticosteroid (e.g. prednisolone 0.5–1 mg/kg/day, given for 5–7 days and then tapered over 2–3 weeks according to response).
• Recommend frequent, liberal use of an emollient to maintain skin hydration and improve barrier repair.
• CKS does not recommend the use of antihistamines for relieving pruritus associated with acute contact dermatitis.

In depth

• Advise people that preventing further episodes of contact dermatitis relies on avoidance of the causative stimulus.
• If complete avoidance is not possible, advise the person on the use of measures aimed at preventing or minimizing contact with affected areas of skin, for example:
• Rinsing with water or washing with soap or, preferably, a soap substitute as soon as possible after contact (overuse of skin-cleaning agents can aggravate contact dermatitis).
• Substituting products that contain identified allergens or irritants with other products that do not contain them.
• Reducing the duration and frequency of contact with an irritant.
• Using protective clothing. Most irritant contact dermatitis involves the hands, and protective gloves are the mainstay of protection.
• Consider appropriate use of a barrier cream. Barrier creams may help to prevent irritant contact dermatitis, but their use as sole protection against contact with allergens or irritants is not recommended.
• Advise the use of emollient soap substitutes.
• Recommend frequent application of emollients.

In depth

• If measures to avoid the stimulus do not resolve dermatitis:
• Reassess the diagnosis.
• Reassess the identity of possible allergens and irritants.
• Refer to a recognized centre for patch testing if not already done.
• Exclude ongoing exposure to irritants or allergens:
• Check compliance with avoidance measures.
• If compliance is good, step up avoidance measures where possible.
• Consider using a more potent topical corticosteroid if response to initial treatment is poor.
• Consider a contact allergy from topical medication (including allergy to topical corticosteroids) if dermatitis fails to respond or deteriorates with use:
• Confirm the suspicion by applying the product on skin that is unaffected by dermatitis and observing for a reaction.
• If allergy from a topical medication is suspected, refer for patch testing to try and identify which topical medication(s) the person is sensitized to.
• Refer to a dermatologist if:
• The person has chronic, recurring, or unrelenting eczematous or lichenified dermatitis despite avoidance measures and appropriate-strength topical corticosteroid treatment.
• There is a suspicion of contact dermatitis but no clear history of relevant exposure.
• Recalcitrant or chronic contact dermatitis does not respond to first-line steroid therapy.

In depth

• Suspect secondary infection if clinical signs of infection are present (e.g. rapid worsening of dermatitis with marked erythema, discharge, or increased pain). The person will often feel unwell or feverish.
• For visibly infected dermatitis, swab the skin and start oral antibiotics:
• Flucloxacillin or clarithromycin (if the person is allergic to penicillin) is recommended first-line.
• If visible infection fails to respond to a first-line antibiotic, microbiological investigations to ascertain sensitivities may be useful.

In depth

• The potency of the topical corticosteroid prescribed depends on the severity of the dermatitis, the size of the area affected, the location of the dermatitis, and whether it is acute or chronic:
• For acute, severe, localized contact dermatitis on the body or limbs, prescribe a potent topical corticosteroid (e.g. betamethasone valerate 0.1%).
• For chronic or more widespread dermatitis (but < 20% body surface area), potency may need to be reduced.
• In children, start treatment with a mildly potent topical corticosteroid (e.g. hydrocortisone 1%).
• For areas of thin skin (e.g. the face or genitals) and in flexures, prescribe a mildly potent topical corticosteroid.
• For areas of thick skin (e.g. palms or soles) and lichenified dermatitis, a potent topical corticosteroid will usually be needed, as penetration of topical corticosteroids is reduced, decreasing the effectiveness.
• The eyelids should be treated only with a mildly potent topical corticosteroid for a maximum of 5 days, taking care to avoid contact of the corticosteroid with the surface of the eye.
• Prescribe a topical corticosteroid in an appropriate formulation for the person and their condition:
• Ointments are recommended in preference to creams because they provide the strongest emollient effect.
• Creams may be preferred by some people, especially when used on visible areas, such as the face and hands:
• Creams are water-based and contain preservatives that can have irritant or allergen potential.
• Other formulations may be more suitable for specific areas of skin, such as the scalp, where liquids and foams will penetrate the hair better.

In depth

• When used correctly, topical corticosteroids rarely cause serious adverse effects.
• The likelihood of adverse effects is directly related to the potency and amount of topical corticosteroids used — a thin layer should be applied once or twice a day, adjusting the potency to control symptoms.
• Systemic adverse effects are rare but include adrenal suppression that can result in symptoms of Cushing's syndrome and in children, growth retardation.
• Local adverse effects are more common:
• Transient burning or stinging is most common and may necessitate changing the product.
• Of more concern is skin atrophy, which is particularly common in the skin of the antecubital or popliteal fossae.
• Hypertrichosis, telangiectasia (especially on cheeks), acne, and steroid-induced contact dermatitis may also occur.

In depth

• Advise the person to apply the corticosteroid in a thin layer to all the affected areas.
• Most products will be supplied with an information leaflet which will specify the number of finger-tip units needed to treat specific body areas. One finger-tip unit is the amount of ointment or cream expressed from a tube with a standard 5 mm diameter nozzle, applied from the distal crease to the tip of the index finger, and is sufficient to treat a skin area about twice that of the flat of the hand with the fingers together.
• For acute episodes of contact dermatitis, advise the person to:
• Apply the topical corticosteroid no more than twice a day. For many people, once-daily application will be sufficient, but this can be increased if response is inadequate.
• Continue treatment for 48 hours after the dermatitis has cleared (if it has not improved after 2 weeks, the person should return for further advice).

In depth

• The choice of emollient should be determined by:
• The dryness of the skin.
• The type of skin to which the emollient is to be applied.
• The individual's preference, determined by the product's tolerability and convenience of use.
• Dryness of skin:
• Less to moderately dry skin is most acceptably treated with a cream.
• Moderately dry to very dry skin requires a higher intensity of treatment with an ointment to restore the skin to normal.
• Weeping dermatitis is best treated with a water-soluble cream, as ointments will tend to slide off, becoming unacceptably messy.
• The tolerability and convenience of a product can only be determined by a trial of treatment:
• Creams are generally better tolerated but will need to be applied more frequently and generously to have the same effect as a single application of ointment.
• The individual will need to balance the tolerability of a product against the convenience of its use and its effectiveness.
• More than one type of product may be required. Different products may be preferred at different times, depending on the intensity of treatment required and the area of skin to be treated (e.g. a cream may be preferable for application to the hands).

In depth

• The most common adverse effect of emollients is irritation caused by sensitivity of the skin to an ingredient in the emollient.
• Skin reactions are usually irritant rather than allergic. The skin shows an immediate and dose-dependent inflammatory response:
• If a skin reaction occurs, stop use of the product and use a different emollient. If the person has had previous skin reactions to emollients, it may be prudent to test a small quantity before widespread application.
• Ingredients commonly implicated in skin reactions to emollients include perfumes and preservatives.
• If sensitivity to emollients is a known problem, the chance of a further reaction is reduced by prescribing a cream with few added ingredients or prescribing an ointment (these do not require preservatives and generally have fewer excipients).
• If the person has reacted to several products, consider referral for patch testing to confirm or exclude contact allergy and to identify the responsible allergen(s).
• The occlusive effect of ointments can cause folliculitis:
• Advise the person to apply the ointment in the direction of hair growth.
• If folliculitis occurs, stop use of the ointment (consider switching to a cream) and use an antibiotic if necessary.
• Emollients can present physical hazards:
• Paraffin-containing products are highly flammable and should not be used near naked flames or whilst smoking.
• Bath emollients can pose a slip hazard.

In depth

• Advise the person to use the emollient liberally and frequently:
• The frequency of application will vary depending on the person's condition and circumstances, but for very dry skin, application of an emollient every 2–3 hours should be considered appropriate.
• To facilitate frequent application, the person should consider keeping separate packs of emollients at work or school.
• It may be more convenient to use better tolerated products (creams and lotions) during the day and ointments at night.
• Advise the person about the effective application of emollients. Emollients should be applied by smoothing them into the skin along the line of hair growth, rather than rubbing them in:
• Creams and lotions are better for red, inflamed areas of skin.
• Ointments are suitable for areas of dry skin that are not inflamed.
• Advise the person to wait several minutes after application of an emollient before applying a topical corticosteroid.

In depth