Chapter 5: The Skin, Hair, and Nails

Anatomy and Physiology Major function of skin is to keep body in homeostasis Heaviest single organ in body – 16% of body weight Three layers – Epidermis – Dermis – Subcutaneous tissue

Anatomy and Physiology Hair, nails and sebaceous and sweat glands are appendages of skin Hair – Vellus hair – short, fine, less pigmentation – Terminal hair – coarser, pigmented (scalp/eyebrows) Nails – Protect distal ends of fingers/toes Sebaceous glands – present all surfaces except palms/soles Sweat glands – help control body temperature

Changes with age: Textbook: pages Skin wrinkles, lax and loses turgor Decrease dermis vascularity Thin, fragile, loose Spots presence Nails changed; thicker, change colour Hair changed: loose colour, number decreased, get smaller,

Colour pigments Melanin Carotene Oxyhemoglobin Deoxyhemoglobin

The Health History Common or Concerning Symptoms – Hair loss – Rash – Moles Ask the patient – “Have you noticed any changes in your skin?...your hair?...?” – “Have you noticed any moles that have changed size, shape, color or sensation?” – “Any new moles?”

Health Promotion and Counseling Clinicians play an important role in educating patients – Early detection of suspicious moles – Protective measures for skin care – Hazards of excessive sun exposure Skin cancers are most common cancers in the U.S.

Skin Cancers Basal Cell Carcinoma – 80% of skin cancers – Shiny, translucent, grow slowly; rarely metastasize Squamous Cell Carcinoma – 16% skin cancer – Crusted, scaly, ulcerated; can metastasize Melanoma – 4% skin cancer – Rapidly increasing in frequency – Spread rapidly

Risk Factors for Melanoma ≥ 50 common moles ≥ 1-4 atypical or unusual moles Red or light hair macular brown or tan spots (usually on sun exposed areas) Heavy sun exposure Light eye or skin color (especially freckles/burns easily) Family history of melanoma

ABCDE: Screening Moles for Possible Melanoma A for asymmetry B or irregular borders, especially ragged, notched or blurred C for variation or change in color, especially blue or black D for diameter ≥ 6mm or different from others, especially changing, itching or bleeding E for elevation or enlargement

Preventive Strategies Reduce sun exposure – Especially midday Ultraviolet B rays (UV-B), most common cause of skin cancer are most intense Use sunscreens

Techniques of Examination Examination of the skin, hair and nails begins with the General Survey of the patient Make sure the patient wears a gown – Drape appropriately to facilitate close inspection of hair, anterior and posterior surfaces of body, palms/soles and webspaces Inspect entire skin surface in good light – Preferably natural light (artificial light that resembles) Artificial light often distorts colors

Techniques of Examination Inspect and palpate skin Note characteristics of: – Color – Moisture – Temperature – Texture – Mobility and Turgor – Lesions

Techniques of Examination Color – Patients often notice change in color before physician – ask them – Look for increased pigmentation, loss of pigmentation – Look for redness, pallor, cyanosis and yellowing Red color of oxyhemoglobin best assessed at fingertips, lips and mucous membranes – In dark-skinned people palms and soles For central cyanosis look in lips, oral mucosa and tongue Jaundice - sclera

Techniques of Examination Moisture – Dryness, sweating and oiliness Temperature – Use back of fingertips – Identify warmth or coolness of skin Texture – Roughness or smoothness Mobility and Turgor – Lift fold of skin – Note ease with which it lifts up (mobility) and speed with which it returns to place (turgor)

Techniques of Examination Lesions – Note characteristics Anatomic location and distribution Patterns and shapes Type of lesion (macules, papules, nevi, vesicle) Color

Techniques of Examination Skin Lesions in Context – Whenever you see a skin lesion try to look it up in a well-illustrated textbook of dermatology – Type of lesions, location and distribution, along with history and physical will help you arrive at a dermatologic diagnosis

Evaluating the Bedbound Patient People confined to bed are particularly susceptible to skin damage and ulceration – Pressure sores result when sustained compression obliterated arteriolar and capillary blood flow to the skin Assess these patients by carefully inspecting skin that overlies sacrum, buttocks, greater trochanters, knees and heels Roll patient onto one side to see sacrum and buttocks

Techniques of Examination Hair – Inspect and palpate – Note quantity, distribution and texture Nails – Inspect and palpate fingernails/toenails – Note color and shape – Note lesions Longitudinal bands of pigment may be a normal finding in people with darker skin

Recording the Physical Examination Initially you may use sentences to describe findings; later you will use phrases Examples: – “Color good. Skin warm and moist. Nails without clubbing or cyanosis. No suspicious nevi. No rash, petechiae or ecchymoses.” – “Marked facial pallor, with circumoral cyanosis. Palms cold and moist. Cyanosis in nailbeds of fingers and toes. One raised blue-black nevus, 1x2cm, with irregular border on right forearm. No rash.”

Tuberculin Skin Test is used for: Detecting tuberculosis (TB) infection. (Which result from Mycobacterium Tuberculosis) Tuberculin Purified Protein Derivative (PPD) is a diagnostic agent. It works by causing a mild, delayed allergic reaction in patients infected with TB or who have had a past infection, which allows for detection of TB.

Route: ID, usually in the inner aspect of forearm Needle gauge ; ml of PPD Reading of test: hours Diameter of indurations 5 mm or more ; in patients with positive HIV, have fibrotic changes in CXR with previous TB 10 mm or more is considered significant in patients with chronic diseases, injection drug users, residents in high risk settings 15 mm or more in patients with no risk factors for TB Negative test; no TB

Scratch Test for Allergens

Allergy skin testing is widely used to diagnose allergic conditions such as: Hay fever Allergic asthma Dermatitis (eczema) Food allergies Penicillin allergy Bee sting allergy Skin testing can be used for people of all ages, including infants and older adults.

Indication for Scratch Test for Allergens Determining allergic response to various antigens to confirm sensitivity to an antigen

During an allergy skin test, patient skin is exposed directly to allergy-causing substances (allergens) and then is observed for signs of a local allergic reaction. Contraindicated if the patient about has anaphylaxis, a life-threatening allergic reaction, or have had a serious reaction to a previous allergy test

How to perform the test In adults, the test is done on the forearm; in children it’s done on the upper back. (The child disrobes from the waist up and lies on his or her stomach). The doctor uses a needle to make small light scratches in the skin under each drop of the substance that may cause allergy, to help the skin absorb the fluid. The scratches aren’t deep enough to cause bleeding. Each drop contains proteins from a separate allergen (a substance that triggers allergy symptoms). The doctor notes where each drop of fluid was placed, either by keeping a chart or by writing a code on the area of skin being tested.

Challenges while doing the procedure! Patients need to stay still long enough (usually about 20 minutes) to give the skin time to react. The skin might tickle or itch during this time, but patients should not be allowed to scratch it. The doctor will examine each needle scratch for redness or swelling. the injection site is measured to look for growth of wheal, a small swelling of the skin. (considered positive test).

Interpretation of reaction Negative; wheal soft with minimal reaction 1+; (wheal) 5-8 mm with minimal erythema 2+; 7-10 mm associated erythema 3+; 9-15 mm associated erythema 4+; 12+ mm with diffuse erythema