“Allergy” is often used as a catch-all for any itchy rash. That is understandable, but it can hide important differences. Eczema can be chronic and dry. Contact dermatitis is linked to something touching the skin. Urticaria produces transient raised wheals. Fungal disease can itch too. The shape, duration and location matter.
Ask how long each individual spot lasts
Hives often appear and fade within hours, with new ones coming elsewhere. Eczema patches tend to persist longer and may become dry, thickened or cracked. Contact dermatitis often follows a distribution linked to jewellery, cosmetics, hair dye, footwear or occupational exposure.
The temptation to keep escalating steroid strength
Topical corticosteroids are valuable eczema medicines when correctly chosen. Problems arise when diagnosis, potency, site and duration are ignored. Face, eyelids and skin folds need particular care. If a rash keeps returning the moment treatment stops, revisit the diagnosis and triggers rather than simply using stronger cream.
Bring your exposures to the appointment
Photos of cosmetics, hair colour, perfume, occupational chemicals and new products can be useful. If you have a recurring hand rash, describe work, glove use and wet work. A good history can sometimes be more useful than a long allergy panel.
Seek urgent medical care for breathing difficulty, swelling of the tongue or throat, widespread blistering, or a rapidly worsening rash with fever.
Related clinic page: General Dermatology