URTICARIA

Papular Urticaria

An acute, sub-acute or chronic inflammation of the skin, caused by endogenous or exogenous agents. Urticaria is an
itchy skin rash.

Causes

  • Endogenous: familial, also associated with other allergic diseases
  • Exogenous: agents include sunlight, chemicals, certain foods, insect bites

Clinical features

  • Inflammation of skin: transient itching hives and wheals
  • Papular urticaria: vesicles, redness, oedema, oozing in site of insect bites

Differential diagnosis

  • Fungal and bacterial infections of the skin
  • Helminth infestations

Investigations

  • No satisfactory investigations for skin allergy
  • Blood: haemogram to demonstrate eosinophilia
  • Stool: microscopy to exclude worms

MANAGEMENT

  • Establish the cause and treat accordingly. Identify what the patient is allergic to.
  • Give an analgesic e.g. paracetamol for any pain or discomfort as necessary
  • Avoid acetylsalicylic acid
  • Give an antihistamine to relieve itching; chlorphenamine 4 mg every 8 hours
    Child: 1-2 mg per dose
  • Or promethazine 25 mg at night. Increase to every 12 hours if necessary
    Child: 1 mg/kg daily in 1-2 divided doses

If severe/unresponsive

  • Prednisolone 1 mg/kg orally once a day for 3-5 days

Prevention

  • Avoid contact with known allergens
  • Treat helminth infections