OVERVIEW

What is prurigo?

Prurigo is a general term for a group of acute or chronic inflammatory skin diseases, primarily characterized by dome-shaped papules and nodules, often accompanied by intense itching.

SYMPTOMS

What are the classifications of prurigo? What are their manifestations?

Prurigo can be divided into acute prurigo, chronic prurigo, and non-specific prurigo-like rashes that appear on the skin during systemic diseases.

• Acute prurigo: Also known as acute simple prurigo or papular urticaria. It manifests as red wheal-like papules, slightly spindle-shaped, with central papules and blisters, 1–2 cm in diameter, often clustered but rarely merging.
• Chronic prurigo: Can be classified into adult prurigo, childhood prurigo, and nodular prurigo.
  • Adult prurigo, also called chronic simple prurigo, chronic papular urticaria, ordinary prurigo, or papular fixed urticaria, commonly occurs on the trunk and limbs. The initial lesions are skin-colored or light red papules or nodules, ranging from millet to soybean size, with possible pinpoint blisters at the top, accompanied by intense itching. Scratching leads to surrounding edema-like erythema, urticarial papules, or blood crusts. The rashes are clustered but never merge.
  • Childhood prurigo, also known as early-onset prurigo or Hebra’s prurigo, mainly affects infants aged 1–3 years, typically on the extensor surfaces of the limbs. Clinically, it presents as recurrent papules or papulovesicles, leaving behind light red, brown-yellow, or skin-colored small nodules.
  • Nodular prurigo, also called verrucous persistent urticaria, verrucous fixed urticaria, or nodular lichen, manifests as verrucous nodular lesions, often distributed on the limbs, especially the extensor surfaces of the lower legs, with severe itching. It usually begins at mosquito bite sites as papules or papulovesicles, gradually developing into firm nodules the size of soybeans or larger, scattered and isolated, accompanied by intense itching.
• Symptomatic prurigo refers to non-specific prurigo-like rashes that appear during certain diseases, including prurigo of pregnancy, lymphoma-associated prurigo, leukemia-associated prurigo, etc.

CAUSES

What are the causes of prurigo?

The exact causes of prurigo are not yet fully understood, but may be related to the following factors:

• Genetic predisposition to allergies
• Arthropod bites
• Endocrine disorders
• Intestinal dysfunction
• Immune factors
• Neuropsychiatric factors
• Infectious factors

Who is prone to prurigo?

Adult prurigo and nodular prurigo are more common in adult women, while acute prurigo and childhood prurigo are more likely to occur in children with allergic constitutions.

DIAGNOSIS

What tests are needed to diagnose prurigo?

• Physical examination:

  • Visual inspection: Observe the location, size, shape, number, color, arrangement, and distribution of the rash.
  • Palpation: Assess whether the rash texture is firm or soft; whether it adheres to surrounding tissues; if there is tenderness; whether there is infiltration or atrophy of the skin lesion; if skin temperature is normal; if there are sensory abnormalities in the rash; and whether lymph nodes around the rash are enlarged.

• Special tests:

  • Patch test: Helps determine the cause of prurigo.
  • Histopathological and immunopathological examinations: Aid in confirming the diagnosis and differential diagnosis of prurigo. Histopathology of prurigo may show hyperkeratosis, acanthosis, and perivascular inflammatory cell infiltration.

TREATMENT

Which department should I see for prurigo?

Dermatology.

Can prurigo be cured? Will it recur?

Acute prurigo can usually be cured after 2-3 weeks of treatment, while chronic prurigo requires a longer treatment period.

Prurigo is easy to diagnose but difficult to treat and prone to recurrence. Patients need to maintain good sleep and dietary habits, avoid insect bites, and prevent repeated episodes of prurigo.

What are the common topical medications for treating prurigo?

• Antipruritics: such as calamine lotion;
• Corticosteroids: anti-inflammatory, anti-proliferative, and antipruritic;
• Calcineurin inhibitors: 1% pimecrolimus can significantly improve itching;
• Vitamin D3 analogs: tacalcitol has a significant improvement effect on prurigo.

What are the common oral medications for treating prurigo?

• Antihistamines: the basic treatment for prurigo;
• Sedative-hypnotics: help improve sleep;
• Corticosteroids: for severe cases, long-term use has many side effects, usually prescribed for short-term use;
• Immunosuppressants: including cyclosporine, colchicine, and tripterygium glycosides, with anti-inflammatory effects;
• Antileprosy drugs: commonly used are thalidomide and lenalidomide, with sedative, antipruritic, and anti-inflammatory effects;
• Retinoids: for hard skin lesions;
• Vitamin C and calcium: adjunctive therapy for prurigo, helps relieve itching.

What are the physical treatment methods for prurigo?

• Liquid nitrogen cryotherapy: low temperature acts on prurigo lesions, causing necrosis and shedding for therapeutic purposes.
• CO2 laser therapy: CO2 laser is far-infrared, precisely targeting the treatment area.
• Ultraviolet radiation: improves immunity, reduces Langerhans cells, decreases antigen presentation, and induces T-cell apoptosis.

DIET & LIFESTYLE

The Psychological Impact of Prurigo on Patients

Prurigo not only affects the skin's appearance but also causes intense itching, severely impairing patients' quality of life. Additionally, due to its recurrent and stubborn nature, patients are prone to developing negative emotions such as anxiety and depression. Psychological disorders can also be a contributing factor for some patients.

Therefore, proactive psychological intervention is crucial for improving treatment efficacy and promoting recovery.

How to Manage Persistent Itching and Scratching During Prurigo Treatment?

The itching caused by prurigo is often severe, and patients should avoid scratching.

Wearing gloves while sleeping or keeping nails short can help prevent worsening of rashes due to scratching. Treatments such as local injections, fire needle therapy, or oral sedative and antipruritic medications may also be used.

Can Moisturizers Be Used During Prurigo Treatment?

Yes.

PREVENTION

How to Prevent Prurigo?

The most important way to prevent prurigo is to identify and eliminate causative factors. This includes preventing insect bites, adjusting dietary habits, maintaining a regular routine, and practicing good hygiene.

• Patients with underlying conditions should actively treat their primary diseases;
• Those with allergic constitutions should avoid exposure to allergens as much as possible;
• Patients affected by psychological factors should receive counseling to relieve tension and anxiety.