Red Spots on Skin: Causes, Red Flags & When to See a Doctor

Red dots (petechiae, macules, papules) can range from benign to life-threatening. Always consider context.

Common Causes by Category

Allergic / Hypersensitivity

• Food/drug allergies → urticaria (hives), morbilliform rash
• Insect bites → papular urticaria
• Contact dermatitis

Infectious

• Viral: measles, rubella, roseola, enteroviruses, COVID-19
• Bacterial: scarlet fever (sandpaper rash), meningococcemia (petechiae/purpura), secondary syphilis
• Fungal: tinea corporis

Inflammatory / Autoimmune

• Eczema, psoriasis, lichen planus
• Vasculitis (palpable purpura)
• Lupus (malar rash, vasculitis)

Vascular / Hematologic

• Petechiae/purpura: thrombocytopenia, coagulation defects, vasculitis
• Cherry angiomas (benign, age-related)

Environmental

• Sunburn, heat rash (miliaria)

Red Flags: Seek Immediate Care

• Non-blanching petechiae/purpura + fever → meningococcemia, sepsis
• Rapid spread, pain, blistering → necrotizing fasciitis, SSSS
• Associated: difficulty breathing, confusion, hypotension
• New rash on anticoagulants

Any unexplained widespread rash, especially with systemic symptoms, needs urgent medical evaluation.