Learn about common skin conditions, allergic reactions, eczema, and healthy skin care.

Allergic Skin Conditions

• Why Do I Have a Skin Rash? Common Causes, Symptoms & Treatment

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Skin Care

• Why Do I Have Blisters, Sores or Crusts on My Skin? Common Skin Infections Explained
• Why Is My Skin Dry, Itchy, Red or Scaly?

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Looking for Something Else?

Browse all of our evidence-based health guides in the Health Library (A–Z) or return to the Homepage to explore another health topic.

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How Can You Tell the Difference?

Condition	Pain	Itching	Blisters	Pus	Honey-Colored Crust	One Side Only	Main Cause
Cold sore	Mild	Mild	✅	Rare	❌	❌	HSV
Chickenpox	Mild	Severe	✅	Rare	❌	❌	VZV
Shingles	Severe	Moderate	✅	Rare	❌	✅	Reactivated VZV
Impetigo	Mild	Mild	Sometimes	Sometimes	✅ Typical	❌	Bacteria
Folliculitis	Mild	Mild	❌	Small pustules	❌	❌	Bacteria
Boil	Moderate–severe	Rare	❌	✅ Typical	❌	❌	Bacteria
Cellulitis	Moderate	Rare	❌	Rare	❌	❌	Bacteria

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What Could the Spot Be?

Appearance	Possible Cause	Usually Contagious?	Needs Assessment?
Flat brown spot after years of sun	Age spot	❌	If changing
Small light-brown spots	Freckles	❌	If unusual/changing
Stable symmetrical mole	Benign mole	❌	Routine monitoring
Raised, waxy “stuck-on” growth	Seborrheic keratosis	❌	If changing or uncertain
Rough sun-damaged patch	Actinic keratosis	❌	Yes—should be assessed
Changing irregular pigmented lesion	Possible melanoma	❌	Prompt assessment
Persistent crusting/bleeding sore	Possible skin cancer	❌	Prompt assessment