Common Skin Infections: Impetigo, Cellulitis and Hives

Auckland GP clinics see a steady stream of skin complaints every week, ranging from mild rashes that settle on their own to rapidly spreading infections that need urgent antibiotic treatment. Three of the most common presentations are impetigo, cellulitis, and hives. Although they often appear together in patient searches, the three conditions have very different causes and treatments. This guide explains what each one looks like, what causes it, when to see a GP, and how each is managed.

Quick note before we start. Impetigo and cellulitis are bacterial skin infections. Hives are an allergic or reactive skin response rather than a true infection. They are grouped here because they often look alarming, are commonly confused, and can occasionally overlap.

Impetigo: school sores

Impetigo, often called school sores in New Zealand, is a highly contagious bacterial skin infection caused by Staphylococcus aureus or Streptococcus pyogenes. It is most common in children aged 2 to 5 but can affect any age.

Symptoms of impetigo

• Red sores or blisters, most often on the face around the nose and mouth, on the hands, or on the knees
• Sores that quickly burst and leave a honey coloured golden crust
• Mild itching, sometimes mild soreness
• Easy spread by scratching, touching, or sharing towels, bedding, or clothing
• Usually no fever or feeling unwell

How impetigo spreads

Impetigo thrives in warm, humid weather and in close contact settings such as early childhood centres, schools, and households. Small cuts, insect bites, eczema, or scratches give the bacteria an entry point. In New Zealand, impetigo rates are highest in Maori, Pacific, and younger age groups, and warm northern months see a seasonal peak.

How a GP treats impetigo

• Gentle cleaning of the area with warm water, and soaking crusts off with a clean wet cloth
• For small localised sores, a topical antibiotic ointment (such as fusidic acid or mupirocin) for five to seven days
• For widespread or severe impetigo, oral antibiotics such as cefalexin or flucloxacillin
• Covering sores with a dressing to reduce the spread
• Keeping children home from school or care until sores have crusted over, or have been on antibiotics for 24 hours

Cellulitis: deeper skin infection

Cellulitis is a deeper bacterial infection of the skin and the tissues just below it, most often caused by streptococcus or staphylococcus bacteria entering through a break in the skin. Unlike impetigo, cellulitis can make you feel unwell and needs prompt treatment.

Symptoms of cellulitis

• A warm, red, swollen area of skin that spreads over hours to days
• Tenderness and pain on touch
• Skin that may look tight or shiny
• Red streaks extending from the area
• Fever, chills, or feeling generally unwell
• Swollen nearby lymph nodes
• Most common on the lower legs, but can occur anywhere

Who is at higher risk

• People with diabetes
• People with poor circulation or lymphoedema
• People with chronic skin conditions such as eczema, tinea pedis (athlete’s foot), or leg ulcers
• People with insect bites, cuts, or surgical wounds
• Immunosuppressed people

Why cellulitis needs prompt GP review. Cellulitis can spread quickly and occasionally progress to bloodstream infection (septicaemia) or deeper tissue infection (necrotising fasciitis). Early treatment shortens the illness and reduces the risk of hospital admission. Call your GP the same day if you notice a spreading red area with warmth, tenderness, and any fever or feeling unwell.

How a GP treats cellulitis

• Examination and marking of the edge of the redness so progress can be tracked
• A course of oral antibiotics, most often flucloxacillin or cefalexin for 7 to 10 days
• Rest and elevation of the affected limb
• Simple pain relief with paracetamol
• Review in 24 to 48 hours to check the redness has stopped advancing
• Some people need intravenous antibiotics in hospital when infection is severe, spreading despite oral treatment, or involving the face

Hives: an allergic or reactive skin response

Hives, also called urticaria, are raised itchy welts on the skin that appear suddenly and usually disappear within 24 hours, although new ones may keep appearing. Hives are not an infection. They are the skin’s reaction to a trigger that causes mast cells to release histamine.

Symptoms of hives

• Raised, pink or pale welts that range from small spots to large patches
• Intense itching
• Welts that move around the body, with each individual welt fading within 24 hours
• Sometimes swelling of lips, eyelids, or hands (angioedema)
• Acute hives last less than six weeks. Chronic hives last more than six weeks

Common triggers

• Viral illness, especially in children
• Foods such as shellfish, nuts, eggs, dairy, or strawberries
• Medications such as aspirin, nonsteroidal anti inflammatories, or antibiotics
• Insect bites or stings
• Physical triggers: cold, heat, pressure, exercise
• In chronic hives, a specific trigger is often never identified

When hives need urgent care. Call 111 or go to the emergency department if hives come with swelling of the tongue, lips, or throat; difficulty breathing, wheezing, or noisy breathing; feeling faint or lightheaded; or a widespread rash with other symptoms that come on suddenly after a new food, sting, or medication. This may be anaphylaxis, which needs urgent adrenaline.

How a GP treats hives

• Identifying and removing the trigger, where possible
• Non-drowsy antihistamines such as loratadine, cetirizine, or fexofenadine as first line
• Higher doses or combinations of antihistamines for chronic hives
• A short course of oral steroids for severe cases
• Referral to an allergy or dermatology specialist when hives are chronic, severe, or come with angioedema

Quick comparison

When to see a GP

Book a GP appointment the same day if:

• You have spreading redness, warmth, and pain in the skin
• You feel unwell, feverish, or have a rapid heartbeat alongside a skin change
• Impetigo is spreading despite home cleaning or after 48 hours of topical treatment
• Hives have been present for more than a few days, come with swelling, or keep recurring
• You have diabetes, are pregnant, or are immunosuppressed, and notice any skin infection

Seek urgent care at ED or call 111 for:

- Breathing difficulty, swelling of lips or throat, or collapse

- Severe spreading infection with very high fever, confusion, or a rapidly expanding dark or purple area

- Skin that is intensely painful out of proportion to appearance (possible deeper infection)

How a GP diagnoses skin infections

At CityMed, skin assessments typically include:

• A full history: when the rash or redness started, any recent injury, insect bite, new medication, food, or travel
• Examination of the affected area with measurement and sometimes photography for comparison at review
• Swabs of crust or blister fluid for impetigo when atypical or recurrent
• Blood tests when severe cellulitis is suspected
• Allergy testing referral for recurrent hives

Prevention

• Wash cuts, scrapes, and insect bites promptly and cover them while healing
• Treat eczema and athlete’s foot early, since these give bacteria an entry point
• Keep fingernails short, especially in children, to reduce scratching
• Wash hands, towels, and bedding regularly during an outbreak of impetigo in the household
• Keep a written list of any known allergies or medication reactions and share it with your GP

Frequently asked questions

Can adults get impetigo?

Yes. Although impetigo is most common in young children, adults can catch it too, especially through close contact in sports or shared bedding with an affected family member.

Is cellulitis contagious?

Cellulitis itself is not contagious because it sits under the skin. However, the bacteria that cause it can spread through broken skin, so good wound care matters in the household.

Will hives go away on their own?

Many cases of acute hives settle within a few days. Antihistamines help relieve itching. Hives lasting more than six weeks are considered chronic and should be reviewed by a GP.

What should I do if I am allergic to penicillin and have cellulitis?

Tell your GP about all known drug allergies. Alternatives such as erythromycin or clindamycin can be used safely in most cases.

Need a skin assessment in Auckland?

CityMed Medical Centre offers GP appointments in Auckland CBD for skin infections, rashes, and allergic skin conditions.

If you are worried about a spreading skin infection, call our reception or book online at citymed.co.nz.