What should you know about a Repatha rash?

A rash appearing after an injection may be related to a medicine reaction, but timing alone cannot prove the cause. The rash could instead reflect contact dermatitis from a product, atopic dermatitis, heat rash, intertrigo or an infection such as ringworm or scabies. Psoriasis can also flare independently. Note the first day, injection site, spread, itch, pain, scaling and any new soaps, adhesives or medicines.

A clinician may compare the rash with photographs, examine the skin and decide whether another diagnosis better explains it. Do not assume every eruption is an allergy, and do not dismiss a rapidly worsening one.

Keep the area clean and avoid scratching, fragranced products and tight clothing. Take clear photographs and record injection dates, the site used and other exposures. Contact the prescriber before stopping, delaying or replacing Repatha; they can weigh the skin symptoms against the reason it was prescribed. Do not apply a prescription steroid or antifungal cream without advice, because the wrong treatment can obscure the diagnosis or irritate infected skin.

Call emergency services for trouble breathing, throat or tongue swelling, faintness or widespread hives after an injection. Obtain urgent medical advice for blistering, peeling skin, painful mouth or eye involvement, fever, facial swelling or a rash that spreads quickly. A local itchy patch without these features still deserves review if it persists, recurs after injections or interferes with sleep.

Ask whether the pattern fits a drug rash or another condition, whether you should use the next scheduled dose and which soothing treatment is safe. Bring the product packaging, photographs, injection schedule and a list of new skin products or medicines.