Pruritus A manifestation of systemic disease

Pruritus A manifestation of systemic disease: 

Pruritus A manifestation of systemic disease Dr : Rabie Fahmy Zahran. Tropical M. Consultant. Damietta Fever Hospital. Egypt. rabiezahran@gawab.com 0124114646

Pruritus: 

Pruritus An unpleasant localized or generalized sensation on the skin , mucus membranes or conjunctivae which the patient unconsciously attempts to relieve by scratching or rubbing. It is a common manifestation of many dermatological conditions , but may also results from systemic diseases. rabiezahran@gawab.com 0124114646

Diversity of Causes and Presentation: 

Diversity of Causes and Presentation Causes may be : Trivial to Life threatening ( mosquito bite ) (malignancy) *Localized itching rarely caused by systemic disease. rabiezahran@gawab.com 0124114646

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*up to 50% of cases with generalized itching without obvious dermatological cause have systemic disease. rabiezahran@gawab.com 0124114646

Poorly Understood & Managed: 

Poorly Understood & Managed Relies on similar components of the pain system: receptors , neurotransmitters , spinal pathways and centers in the brain Stimulating pain can relief itching Treating pain with some analgesics relieves itching, others trigger itching Pruritus is a common side-effect of opioid administration, sometimes worse than the pain rabiezahran@gawab.com 0124114646

Pruritogenic Stimuli: 

Pruritogenic Stimuli Pressure Low-intensity electrical or punctate stimuli. Histamine: acts directly on free nerve endings in skin rabiezahran@gawab.com 0124114646

Pain vs Itch Nerves: 

Pain vs Itch Nerves Itch transmitted from specialized pain receptors: a subclass of C- nociceptors Mechano -insensitive Histamine sensitive Nerve endings cluster around “itch points” which correspond to areas very sensitive to pruritogenic stimuli rabiezahran@gawab.com 0124114646

Itch pathways: 

Itch pathways Fibers originate @ dermal/epidermal jxn  Thin unmyelinated axons, lots of branching  Ipsilateral dorsal horn of spinal cord  Synapse with itch-specific secondary neurons Cross to opposite anterolateral spinothalamic tract to thalamus  Somatosensory cortex of postcentral gyrus SLOW transmission and BROAD receptor field rabiezahran@gawab.com 0124114646

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Itch Mediators: 

Itch Mediators Histamine. Prostaglandins. Leukotrienes. Serotonin. Acetylcholine. Substance P Proteases. Peptides. Enzymes. Cytokines. rabiezahran@gawab.com 0124114646

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*Itching is a common complaint that may reflect underlying systemic disease. *General practitioners are equipped to identify the more common cutaneous and non-cutaneous causes of itching. rabiezahran@gawab.com 0124114646

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* Dermatology consultation may be warranted if the diagnosis is unclear or the condition does not respond to treatment. rabiezahran@gawab.com 0124114646

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Evaluation of a patient complaining of itch rabiezahran@gawab.com 0124114646

The first step: 

The first step rabiezahran@gawab.com 0124114646

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The first step is to : Determine if it is caused by a skin condition or a systemic disease . The physician should attempt to identify primary skin lesions or any evidence of infestation. It is excellent not to miss the diagnosis of the Ten major dermatological causes of pruritus . rabiezahran@gawab.com 0124114646

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Ten major dermatological causes of pruritus Scabies. Dermatitis herpetiformis . Atopic dermatitis. Lichen simplex chronicus. Bullous pemphigoid. Drug hypersensitivity. Urticaria. Xerosis (winter itch). Mycosis fungoides. Psoriasis. rabiezahran@gawab.com 0124114646

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(1) Scabies skin exam. may reveals burrows . rabiezahran@gawab.com 0124114646

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(2) Dermatitis herpetiformis pruritic autoimmune blistering disorder associated with a gluten-sensitive enteropathy (GSE). characterized by grouped excoriations; erythematous , urticarial plaques; and papules with vesicles. Common sites: extensor surfaces of the elbows, knees, buttocks, and back. rabiezahran@gawab.com 0124114646

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(4) Atopic dermatitis pruritic disease of unknown origin . starts in early infancy (an adult-onset variant is recognized); it is characterized by pruritus, eczematous lesions,xerosis , thickening of the skin. may be associated with other atopic diseases ( eg , asthma, allergic rhinitis, urticaria , acute allergic reactions to foods). rabiezahran@gawab.com 0124114646

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(4) Lichen simplex chronicus rabiezahran@gawab.com 0124114646 pruritic plaques with thickening of the skin occurs on any location : *Scalp *Nape of neck *Extensor forearms and elbows *Vulva and scrotum . *Upper medial thighs, *knees, *lower legs, *ankles

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(5) Bullous pemphigoid chronic, autoimmune , subepidermal , blistering skin disease that rarely involves mucous membranes. characterized by the presence of immunoglobulin G ( IgG ) auto-antibodies precipitated by ultraviolet irradiation, x-ray therapy, and exposure to some drugs. Like: furosemide , ibuprofen and other nonsteroidal anti-inflammatory agents, captopril , penicillamine , and antibiotics. rabiezahran@gawab.com 0124114646

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(6) Drug hypersensitivity rabiezahran@gawab.com 0124114646

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(7) Urticaria rabiezahran@gawab.com 0124114646

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(6) Xerosis (winter itch) rabiezahran@gawab.com 0124114646

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(9) Mycosis fungoides rare form of T-cell lymphoma of the skin . the disease is typically slowly progressive and chronic. the skin becomes infiltrated with plaques and nodules that are composed of lymphocytes. rabiezahran@gawab.com 0124114646

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(10) Psoriasis chronic , relapsing , i nflammatory skin disorder with a strong genetic basis . The plaque type of psoriasis is the most common, rabiezahran@gawab.com 0124114646

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The second step rabiezahran@gawab.com 0124114646

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The second step is to proceed to : * general history . * physical exam : # the review of systems and a search for : + Adenopathy , + Organomegaly . + Icterus . *A complete medication list is especially important, as medications must be ruled out as a possible cause of itching with or without a rash. rabiezahran@gawab.com 0124114646

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# Medications that provok itching by causing cholestasis : * phenothiazines (antipsychotic ) , * tolbutamide (oral anti-diabetic ) , *erythromycin, *estrogen , * progestin . *testosterone. rabiezahran@gawab.com 0124114646

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# Other drugs that can cause itching include : -morphine, -cocaine, -Butorphanol (Stadol) a morphinan-type synthetic opioid analgesic , -aspirin, - quinidine . -vitamin B complex. NB . :Even if the patient has been taking the medication for years it may still cause itch . rabiezahran@gawab.com 0124114646

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Note is itch is generalized or localized: *Itching of internal disease tends to be fairly generalized and not associated with primary lesions . Some exceptions exist, including the localized Anogenital itching of diabetes mellitus . rabiezahran@gawab.com 0124114646

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Note sequence of events : * Itch precedes rash = suggestive of : + systemic disorder. + psychogenic pruritus. Rash precedes itch = suggestive of cutanious disease. Rash secondary to itching & scratching suggestive of : + atopic dermatitis. + some cases of psychogenic pruritus. rabiezahran@gawab.com 0124114646

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Note character of the sensation : * Itching = atopic dermatitis or other dermatological disease . * stinging , pricking burning = psychogenic pruritus rabiezahran@gawab.com 0124114646

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*Secondary changes from rubbing and scratching may be present. It is important not to mistake them for primary skin disease and make a mis -diagnosis of Aquagenic pruritus (itching provoked by bathing) may occur with : * xerosis . *polycythaemia vera . *Hodgkin’s disease. * mastocytosis . rabiezahran@gawab.com 0124114646

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third step rabiezahran@gawab.com 0124114646

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If no cause is identified after a thorough history and physical exam, the third step in evaluation includes a search for occult disease. rabiezahran@gawab.com 0124114646

What Occult systemic disease which might cause Pruritus .: 

What Occult systemic disease which might cause Pruritus . rabiezahran@gawab.com 0124114646

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Five important systemic causes of itching (1) Hepatobiliary . (2) Renal. (3) Endocrine. (4) Haematological . (5) Malignancies. rabiezahran@gawab.com 0124114646

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1-Hepato-biliary causes 1) Primary Biliary cirrhosis. 2) Biliary obstruction. 3)Cholestasis during pregnancy. rabiezahran@gawab.com 0124114646

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1-Hepato-biliary: *The pathophysiology of itch in hepatobiliary disorders is not clear . *Attrib to bile salts in serum and tissues. * Endogenous opioids may play a causative role. *Itching may be the presenting complaint of drug-induced hepatic cholestasis (e.g. oral contraceptives ) or malignancy that causes biliary obstruction . *There may be a predilection for the hands and feet . rabiezahran@gawab.com 0124114646

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rabiezahran@gawab.com 0124114646 1-Hepato-biliary pruritus may precede the development of jaundice by months, and is the presenting symptom in half of the patients. Treatment : reverse cholestasis , liver transplant Also helpful: *oral guar gum (dietary fiber) *binds bile acids; cholestyramine ; * rifampin ! (inhibits bile uptake), * opioid antagonists, codeine. * ondansetron ( zoferan )= serotonin receptor antagonist . Not helpful: scratching

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2-Renal Chronic renal failure (even on dialysis) rabiezahran@gawab.com 0124114646 Itching is rarely the presenting complaint in renal disease. Often the diagnosis of renal insufficiency is established before itching develops. Attributed to accumulation of : histamine ( mast cells) , serotonin Ca, Phos , Mg, Al, vit A also implicated . Ultraviolet B phototherapy Inhibits histamine release & proliferation of dermal mast cells. Antihistamines are not effective

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3-ENDOCRINE DISORDERS *Hyperthyroidism , *hypothyroidism , *diabetes mellitus. * carcinoid syndrome. All may be associated with pruritus. Both hyper- and hypothyroidism can present with itch. If hyperthyroidism is discovered, treating it results in clearance of itch, Use of emollients for dry skin in hypothyroidism leads to improvement. Localized anogenital pruritus occurs in diabetic patients and may be caused by mucocutaneous candidiasis rabiezahran@gawab.com 0124114646

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4-HAEMATOLOGICAL DISORDERS (1) Polycythaemia vera often presents with aquagenic pruritus. The itch begins after emerging from a bath or shower and lasts for 15–60 minutes . No visible skin changes are present . Pruritus results from increased histamine levels released from increased basophils and mast cells. Patients with aquagenic pruritus should be followed periodically for development of polycythaemia vera because the symptoms may precede diagnosis by months . Pruritus and iron deficiency may occur in patients with polycythaemia vera & correction of the iron deficiency may result in improvement. rabiezahran@gawab.com 0124114646

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HAEMATOLOGICAL DISORDERS (2) Other Myeloproliferative disorders ( leukaemia,monoclonal gammopathy & multiple myeloma Lymphoma ) (3) iron deficiency anemia that is unassociated with polycythaemia vera, may be associated with pruritus rabiezahran@gawab.com 0124114646

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5-MALIGNANT NEOPLASMS The association of malignancy and generalized itching is quite rare of all malignancies : 1: Hodgkin’s disease : more frequently presents with Pruritus, which may precede the diagnosis by months. The severe& often burning itch of Hodgkin’s disease responds only to treatment of the underlying lymphoma. rabiezahran@gawab.com 0124114646

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rabiezahran@gawab.com 0124114646 MALIGNANT NEOPLASMS 2: Cutanious T-cell lymphoma : (e.g. mycosis fungoides ). 3:Visceral cancers : - adenocarcinoma. -squamous cell cancers of various organs. 3: CNS . tumors . 4: multiple myeloma .

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INFECTION Patients with infectious diseases, most notably: * parasitic. *HIV infection , can present with pruritus without easily recognized primary skin lesions. The itch of HIV may be secondary to co-morbid conditions such as: *scabies, * seborrhoea . * candidiasis . * folliculitis . *lymphoma . but it may also result from the direct effects of the virus . rabiezahran@gawab.com 0124114646

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PSYCHOGENIC ITCHING *Psychogenic pruritus is diagnosed by exclusion . *It is especially important to consider and exclude scabies and pediculosis . *Some patients may have delusions of parasitosis or neurotic excoriations. *These patients complain of the sensation of insects crawling across or emerging from the skin . *Delusions of parasitosis may respond to pimozide ( Antipsychotic) . rabiezahran@gawab.com 0124114646

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Laboratory testing is guided by the patient’s history and physical findings. Often the evaluation will begin with simple and inexpensive tests . rabiezahran@gawab.com 0124114646

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Laboratory investigation Done for pruritic patient who does not have a primary dermatological disease. Routine screening tests : *Serum glucose. *Complete blood count with differential. *Liver function tests. *Renal function tests (blood urea nitrogen, creatinine . *Urinalysis. *Thyroid function tests. *Iron studies. *Stool for occult blood. *Chest X-ray. rabiezahran@gawab.com 0124114646

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Additional testing *Serum protein electrophoresis. *ESR. *Anti-mitochondrial antibodies. *Stool for ova and parasites. * Papanicolaou smear (cervical smear to detect premalignant cervix ) . *HIV testing. *Imaging studies (CT scan, ultrasonography , mammography). rabiezahran@gawab.com 0124114646

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TREATMENT. rabiezahran@gawab.com 0124114646

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TREATMENT: * Identify & diagnose the specific cause & try to treat . *Factors known to make itching worse should be reduced. *Dry skin may be improved by: = changing to milder soap, = minimising exposure to soap, =limiting bathing, =avoiding hot water = applying emollients and humidifying dry environments . rabiezahran@gawab.com 0124114646

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TREATMENT: * Stress can reduce the itch threshold and an effort should be made to address it. *The sensation of itching is increased if the skin is warm, and measures to keep the skin cool can be undertaken. * Topical preparations for itch should begin with moisturising emollients and menthol preparations. *Topical pramoxine creams or lotions may help. *Topical antihistamines are generally not recommended as they may result in contact dermatitis. *Once a diagnosis is established, topical steroids may be used to treat steroid-sensitive conditions. rabiezahran@gawab.com 0124114646

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Thank you rabiezahran@gawab.com 0124114646