About this condition
Allergic contact dermatitis is an immune-mediated skin reaction that develops after contact with a substance to which a person has become sensitised. It must be distinguished from common irritant dermatitis.
What you should know
Symptoms often affect hands, face, neck or other exposed sites. Reactions may be delayed, so the most recent product is not necessarily the cause. Metals, fragrances, preservatives and occupational substances may be relevant in some people.
When to seek medical advice
Redness, itching, dry or cracked skin, scaling and small blisters are possible. Repeated flares in the same areas, the timing of product use and workplace exposures are important details to record.
Important distinctions
Irritant dermatitis damages the skin barrier without requiring allergy, whereas allergic contact dermatitis follows immune sensitisation. The rashes can look similar, and a photograph alone cannot confidently distinguish them.
How assessment works
Diagnosis uses the history, exposure pattern and skin examination. Dermatology patch testing may be appropriate in selected patients to identify specific contact allergens; its mention here does not mean that testing is offered by this clinic.
Management and limitations
The main approach is avoiding a confirmed trigger when practical, protecting the skin barrier and clinician-guided treatment of inflammation. Repeatedly changing many creams without identifying the cause can make evaluation harder.
When emergency help is needed
Ordinary contact dermatitis rarely requires an ambulance. Rapidly spreading painful rash with fever, blisters or mucosal involvement requires urgent review; call 103 or 112 if tongue or throat swelling or breathing difficulty develops.
Related information
Allergic rhinitis; Urticaria (hives); Allergy to insect bites and stings.
Signs and symptoms
Redness, itching, dry or cracked skin, scaling and small blisters are possible. Repeated flares in the same areas, the timing of product use and workplace exposures are important details to record.
Diagnosis and tests
Diagnosis uses the history, exposure pattern and skin examination. Dermatology patch testing may be appropriate in selected patients to identify specific contact allergens; its mention here does not mean that testing is offered by this clinic.
Care and treatment approaches
The main approach is avoiding a confirmed trigger when practical, protecting the skin barrier and clinician-guided treatment of inflammation. Repeatedly changing many creams without identifying the cause can make evaluation harder.
When to seek urgent care
Ordinary contact dermatitis rarely requires an ambulance. Rapidly spreading painful rash with fever, blisters or mucosal involvement requires urgent review; call 103 or 112 if tongue or throat swelling or breathing difficulty develops.
Frequently asked questions
How is allergic dermatitis different from skin irritation?
Allergic dermatitis involves immune sensitisation; irritant dermatitis results from skin barrier damage without that allergy mechanism.
Does the rash always appear immediately after exposure?
No. Allergic contact reactions may be delayed, so a detailed timeline of exposure is useful.
Does everyone need patch testing?
No. Specialist testing is selected according to recurrent symptoms, history and clinical examination.
Important information
A medical consultation is needed for diagnosis and treatment recommendations.
Self-treatment can be harmful to your health.
