What Is Itchy Skin A Sign Of?

Itching may be a sign of a skin problem or a more serious systemic disorder. Skin itching is also a side effect of some medications.

Itching is a common symptom experienced by all humans at some point in their lives. Itchy skin can be a symptom of many different conditions including 

• skin disorders (Dermatologic disorders),
• neurological problems (neuropathic itch),
• systemic illness,
• psychiatric conditions,
• infections, and
• Medications.

The medical term for itching is pruritus such as prurigo nodularis and lichen simplex chronicus.

Itching is a symptom of many types of disorders. Itching may occur in one localized area, or it may be generalized all over the body. Itching can range from mild to intense. 

Some symptoms that may accompany itchy skin include:

• Skin redness
• Dry skin
• Cracked skin
• Bumps or spots
• Blisters
• Rash
• Leathery or scaly skin
• Flaky skin or scalp
• Sensations of burning, pain, or sensory loss (in patients with neuropathic disease)

5 Main causes of itchy skin may include:

Dermatologic (skin) disorders

• Xerosis (areas of dry, scaly skin) 
• Eczematous dermatitis: inflammatory patches or plaques on the skin
• Atopic dermatitis: a chronic, itchy, inflammatory skin disorder
• Contact dermatitis: any skin itching or inflammation that results from contact between a substance and the skin
• Hives (urticaria)
• Papulosquamous disorders: include psoriasis, lichen planus, pityriasis rubra pilaris, and others 
• Skin infections and infestations: Common infectious causes include:
  • Dermatophyte infections such as tinea cruris, tinea pedis, tinea capitis
  • Folliculitis
  • Scabies mite infestation and pediculosis capitis, corporis, or pubis 
  • Other arthropod bites such as mosquitoes, ticks, black flies, horse and deer flies, sand flies, stable flies, biting midges, fleas, centipedes, and biting mites
• Secondary skin disorders: scratching or rubbing itchy skin can lead to skin conditions such as lichen simplex chronicus and prurigo nodularis
• Scars, particularly burn scars and keloids 

Systemic disorders 

• Allergies/allergic reactions
• Autoimmune blistering diseases, such as bullous pemphigoid and dermatitis herpetiformis, and other disorders, such as cutaneous mastocytosis
• Kidney (renal) disease
• Liver disease  
• Endocrine disease 
  • Thyroid disease
  • Diabetes
• Cancer
  • Hodgkin lymphoma and non-Hodgkin lymphoma
  • Mycosis fungoides
  • Polycythemia vera
  • Leukemias
  • Plasma cell blood disorders
  • Gastric carcinoid tumors

Infections

• Primary varicella-zoster virus infection (chicken pox)
• HIV infection 
• Systemic rheumatic disease 
• Dermatomyositis
• Systemic sclerosis (scleroderma)
• Primary Sjögren's syndrome 

Drug reactions 

• Systemic retinoid therapy
• As an associated feature of drug-induced phototoxicities, such as that which may follow doxycycline therapy
• Opiates
• Molecularly targeted and immunotherapeutic antineoplastic agents

Neurologic disorders (neuropathic itch) 

• Brachioradial pruritus
• Notalgia paresthetica
• Postherpetic neuralgia
• Multiple sclerosis 
• Small fiber neuropathies (disorders of small nerve fibers associated with autonomic and sensory symptoms) 
• Psychogenic itch: occurs with psychiatric illnesses or somatoform disorders
  • Psychogenic excoriation (also known as neurotic excoriation) - individuals excessively pick and scratch normal skin
  • Psychologic stress 
  • Delusional infestation 
• Illicit drug use involving opioids, cocaine, or amphetamines 
• Itching, like yawning, may also be contagious, causing people to feel the urge to scratch when they see another person scratching. 

Itchy skin is diagnosed with a history and physical examination of the skin. A healthcare provider will look for the presence of lesions on the skin, ask whether the itching is localized to one area or generalized all over the body, how long the itching lasts, and what triggers the itching, makes the itching worse, and also what might relieve the itching. 

A healthcare provider will usually start by looking for primary skin lesions, which suggest the itching may be caused by a skin disorder. If there are secondary skin lesions (such as scratches or abrasions, areas of darker skin, or skin thickening called lichenification) that may suggest the itching is caused by systemic, neurologic, or psychogenic factors.

If there are primary skin lesions present, diagnostic tests may include: 

• Skin biopsy 
• Potassium hydroxide preparation for cutaneous fungal infections

If primary skin lesions are absent, testing to diagnose underlying systemic illness may include:

• Complete blood count with differential to evaluate for evidence of certain cancers or iron deficiency
• Serum bilirubin, transaminases, and alkaline phosphatase to check for liver disease
• Thyroid-stimulating hormone to identify thyroid disorder 
• Blood urea nitrogen and creatinine to diagnose kidney (renal) disease
• Chest X-ray to evaluate for evidence of swollen lymph nodes
• HIV testing
• Immunofluorescence studies and enzyme-linked immunosorbent assay to detect bullous pemphigoid
• Stool testing for ova and parasites
• Hepatitis B and C serologies
• Serum protein electrophoresis and immunoelectrophoresis (if a plasma cell disorder is suspected)

In some cases, modifying the environment may help relieve itchy skin. If itching is localized, treatment may include topical medications. If itching is generalized, oral medications may be needed. 

Environmental modifications that may help prevent or relieve itching skin include:

• Moisturizing skin regularly
• Lotions that have calamine or menthol may provide additional relief
• Keep the environment cool. Lower the air conditioning, and use lukewarm (not hot) water to bath
• Avoid substances known to irritate the skin, including certain cleansing products or wool clothing
• Practice stress reduction techniques such as meditation, acupuncture, and yoga 
• Take measures to prevent scratching by covering itchy areas or keeping fingernails trimmed to a short length

Topical medications to treat localized itchy skin include:

• Topical corticosteroids 
• Topical capsaicin 
• Topical calcineurin inhibitors 
• Topical anesthetics 
• Topical antihistamines 
• Topical phosphodiesterase 4 inhibitors 

Systemic therapies to treat generalized itchy skin include:

• Antihistamines 
• Opioid receptor antagonists 
• Antidepressants 
• Anticonvulsants 
• Aprepitant 
• Thalidomide 
• Immunosuppressants  
• Biologic agents 
• Phototherapy