Itchy skin

Itchy Skin (Pruritus)

Overview
Itchy skin, also known as pruritus, is a common symptom that can occur due to a wide variety of causes. It may be localized (affecting a small area) or generalized (affecting the whole body). Persistent itching can lead to scratching, which may cause skin damage, infections, and a reduced quality of life. Pruritus is not a disease but rather a manifestation of an underlying condition, ranging from dermatological problems to systemic diseases.

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Causes

1. Dermatological conditions

   • Eczema (atopic dermatitis)

   • Psoriasis

   • Contact dermatitis (allergic or irritant reaction)

   • Fungal skin infections (ringworm, candidiasis)

   • Scabies or lice infestations

   • Urticaria (hives)

2. Systemic diseases

   • Liver disease (cholestasis, hepatitis, cirrhosis)

   • Kidney failure (uremia-related pruritus)

   • Thyroid disorders (hyperthyroidism, hypothyroidism)

   • Diabetes mellitus

   • Iron deficiency anaemia

   • Certain cancers (lymphoma, leukemia)

3. Medication-related

   • Opioids (e.g., morphine)

   • ACE inhibitors (e.g., lisinopril)

   • Statins

   • Antimalarials (chloroquine, hydroxychloroquine)

   • Antibiotics (penicillins, sulfonamides)

4. Physiological/other causes

   • Pregnancy (intrahepatic cholestasis of pregnancy, hormonal changes)

   • Dry skin (xerosis), especially in older adults

   • Allergies (food, insect bites, environmental allergens)

   • Psychological factors (anxiety, stress)

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Diagnosis

• History & examination: Onset, duration, pattern, associated symptoms (rash, jaundice, weight loss, fever).

• Laboratory tests: Liver function tests, kidney function, thyroid panel, blood glucose, complete blood count.

• Skin tests/biopsies: If dermatological disease is suspected.

• Allergy testing: In cases of suspected hypersensitivity.

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Treatment
Treatment depends on the underlying cause. General approaches include:

1. Topical treatments

   • Emollients and moisturizers (urea, glycerin, paraffin-based creams).

   • Topical corticosteroids (hydrocortisone 1% cream, betamethasone valerate) for inflammatory causes like eczema or dermatitis.

   • Topical antihistamines (diphenhydramine cream, but use with caution due to sensitization risk).

   • Calamine lotion or menthol-based creams for cooling relief.

2. Oral medications

   • Antihistamines:

     • Non-sedating: Cetirizine 10 mg daily, Loratadine 10 mg daily, Fexofenadine 180 mg daily.

     • Sedating: Hydroxyzine 25–50 mg at night, Diphenhydramine 25–50 mg as needed.

   • Corticosteroids: Prednisolone (short course, dose individualized) in severe inflammatory or autoimmune causes.

   • Gabapentin or pregabalin: For neuropathic itch.

   • Cholestyramine: For liver-related pruritus.

   • Mirtazapine (15–30 mg nightly) or SSRIs (paroxetine, sertraline) in refractory cases linked with systemic disease or psychological components.

3. Lifestyle and supportive measures

   • Avoid hot baths and harsh soaps.

   • Keep skin moisturized.

   • Wear loose cotton clothing.

   • Use mild, fragrance-free detergents.

   • Maintain a cool, humid environment to reduce skin dryness.

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Precautions

• Avoid excessive scratching to prevent skin infections.

• If itching persists for more than 2 weeks, or if it is associated with systemic symptoms (jaundice, weight loss, fever, night sweats), seek medical evaluation.

• Pregnant women with severe itching should see a doctor to rule out intrahepatic cholestasis.

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Drug Interactions

• Antihistamines may interact with alcohol, sedatives, or other CNS depressants, increasing drowsiness.

• Corticosteroids may interact with NSAIDs (increasing risk of GI bleeding), immunosuppressants, and certain antifungals.

• Cholestyramine may reduce absorption of fat-soluble vitamins and other drugs (warfarin, digoxin, thyroxine).

• Gabapentin/pregabalin may enhance sedation if combined with opioids or alcohol.