Skin Rash Assessment

When to arrange an assessment

• A rash that has lasted more than a couple of weeks without settling
• A rash that keeps returning in the same place or in the same circumstances
• Itch that is disturbing sleep or daily activity
• A rash that started after a new medication, product, workplace exposure or travel
• A rash that is not responding to treatment already tried

Possible causes and contributing factors

• Contact reactions, from either an irritant or an allergy to something touching the skin
• Eczema and other forms of dermatitis
• Fungal, bacterial and viral infections
• Inflammatory conditions such as psoriasis or lichen planus
• Urticaria (hives), which may be triggered or may have no identifiable trigger
• Medication reactions, which can appear days to weeks after starting a drug
• Rashes reflecting a general medical or autoimmune condition

Because these overlap in appearance, the diagnosis often depends more on pattern and history than on how any single patch looks.

What happens during the consultation

You will be asked when the rash began, how it started and spread, whether it itches, burns or hurts, whether it comes and goes, and what makes it better or worse. New medications, products, occupational and hobby exposures, travel, contacts with similar rashes and your general health are all relevant.

Examination usually involves more than the area you are worried about, because distribution across the body is often the most useful clue. Nails, scalp and mouth may be checked where relevant.

Assessment and possible investigations

• Skin scrapings or swabs where a fungal or bacterial infection is suspected
• Blood tests where a systemic cause or a drug reaction is being considered
• A small skin biopsy where the diagnosis remains unclear
• Referral for patch testing where an allergic contact cause is suspected

Treatment and management planning

Management follows the likely diagnosis: removing or avoiding a trigger, restoring the skin barrier, treating infection where present, or reducing inflammation. Where the diagnosis is uncertain, a treatment trial with planned review is sometimes reasonable, and the review point is agreed in advance so a rash is not treated indefinitely without a diagnosis.

Suitability, limitations and referral

A rash cannot be diagnosed online, by email or from a photograph alone, and this website does not attempt to do so. Where a rash is widespread, recurrent without explanation, associated with systemic symptoms, or does not respond as expected, referral to a dermatologist, immunologist or another specialist is discussed, and your usual GP may be involved.

Preparing for your appointment

• Photograph the rash when it is at its worst, especially if it comes and goes
• Bring every current medication, including anything started in the last three months
• Bring the products applied to your skin, or photographs of their ingredient lists
• Wear clothing that allows the affected areas to be examined easily
• Note any workplace, hobby or travel exposures around the time it started