Understanding Skin and Nail Conditions: A Comprehensive Overview
1. Melanocytes:
• Originate from the neural crest.
• Found in the basal layer of keratinocytes.
• Large clear cytoplasm.
• Dendritic processes reaching the basal layer, spinous, and granulocytes.
• Melanosomes: melanin.
• Melanoepidermic unit: 1 melanocyte to 36 keratinocytes.
• Number is constant, independent of race or gender, but varies by body areas.
• Pigmentation depends on the size and distribution of melanin granules in keratinocytes.
• Affects skin, hair, and eyes.
• There are 2 types of melanin: eumelanin (black-brown, large, oval melanosomes) and pheomelanin (red-yellow, small, round melanosomes). White hair does not produce melanin; albinos produce only a little melanin, primarily pheomelanin.
2. Hypodermis:
• Subcutaneous tissue, adipose tissue.
• Composed of adipocytes or lipocytes.
• The cells produce and store fat.
• Appearance of signet ring cells with a peripheral kernel.
• The thickness of the lobes varies by body region, being higher in the abdomen, for example.
• Functions: protective, thermal, and caloric reserves.
3. Dyshidrotic Eczema:
Small vesicular elements and hard.
• Bilateral and symmetrical.
• Itching.
• Location: hands and feet, lateral surfaces of the fingers, palms, and soles. Also on the back of the fingers.
• The vesicles can grow and become blisters.
• Recurrent outbreaks.
• Can hamper mobility.
• Etiology:
– Atopic dermatitis.
– Psychic stress factors.
– Foods or medication.
– Relation with eccrine sweat glands (nickel).
• Treatment:
– Etiological or symptomatic (systemic antipruritics, sedatives, antihistamines, topical corticosteroids, or emollients, corticosteroids, or keratolytics).
4. Juvenile Plantar Dermatitis:
Localized form of atopic dermatitis in the feet, often with dry skin. Appears between 3 and 14 years without sex predominance.
It usually occurs on the plantar surface of the toes and heel, also on the back of the fingers and/or affecting the entire plantar surface. Bilateral and symmetrical.
The factors that facilitate its emergence are: maceration, friction, use of athletic shoes, and fiber socks. There is a decline in winter and summer due to pools.
Clinical: erythema, keratosis, peeling, and cracking. Itching leads to scratching, which facilitates staphylococcal infection.
5. Erosive Lichen Planus:
• Erosions and very painful.
• Crusting blisters may precede or not.
• More common on the palms but sometimes occurs on the soles.
• Variable extension.
• Associated with nail lesions: onycholysis, anonychia, and bacterial superinfection.
• Evolution by outbreaks. Chronic course.
• Predominance in women and the elderly.
• Treatment: oral antihistamines, oral corticosteroids and/or topical, topical immunomodulators, oral retinoids, cyclosporine A, and sometimes surgery.
6. Acute Simple Prurigo:
• Papulovesicular dermatosis.
• Type IV hypersensitivity to insects and arthropods.
• Very itchy.
• Occurs in spring/summer, affecting children and adults.
• The elementary lesion is a papule with a hat or seropapule of Tommasdi. Erythematous papule with a tiny base, urticarial, and a blister on top. Sometimes blisters occur.
• Scratching produces the rupture of vesicles, crusts, and superinfection.
• Located on the face, extremities, and exposed areas. Generally respects genitals but may spread.
• Etiopathogenesis involves an individual with atopic constitution, bite, or contact with insects and arthropods (hypersensitivity reaction type IV).
• Treatment: disinfect clothing, furniture, and pets; use insect repellent; antihistamines; topical antiseptics; topical corticosteroids; oral and topical antibiotics.
7. Erythema Nodosum:
• Distribution by sex and age varies according to etiology.
• More common in middle-aged women.
• Location: anterior and lateral surfaces of the legs, back of the feet, thighs, and buttocks. Rare in arms.
• Clinical:
– Hot-erythematous nodules, prominent, painful, and ill-defined that do not ulcerate.
– Sometimes surrounded by a peripheral scaly area.
– They can coalesce into plaques.
– Present a violet to yellow-brown color, disappearing without scarring (contusiform dermatitis).
– Resolution in 4-6 weeks.
• Etiology:
– Infections: chlamydia, strep, tuberculosis, leprosy, yersinia, salmonella, and viruses such as hepatitis or infectious mononucleosis.
– Sarcoidosis.
– Inflammatory diseases: ulcerative colitis and Crohn’s disease.
– Medications: antibiotics, sulfonamides, anxiolytics, and oral contraceptives.
– Pregnancy.
– Neoplasms: lymphomas and leukemias.
– Idiopathic.
• Treatment:
– Etiological treatment.
– Rest.
– NSAIDs.
– Oral corticosteroids.
– Immunosuppressants.
– Potassium iodide.
8. Palmoplantar Psoriasis:
Type Barber. It is the most common pustular form. The pustules are embedded in the epidermis. Plaques are erythematous, circinate, pustular, and scaly. Itchy, painful, and cracking. Almost always bilateral and symmetrical. In the hands, it appears in the thenar or hypothenar areas, and in the feet, it appears in the arch, heel, and inner edge. Evolution by recurrent outbreaks (pustules, crusts, scales).
• Treatment:
– General: Omedas.
– Local: keratolytics (salicylic acid 5-20%, 10-30% urea), retinoids (retinoic acid), corticosteroids, vitamin D derivatives (calcipotriene).
– Systemic: phototherapy, heliotherapy, UVB phototherapy, retinoids, cytostatics, immunosuppressants, steroids, and biologic therapies.
9. Black or Pseudocromohidrosis Plantar:
• Irregular blue-black plates on the posterior or posterolateral heel (one or both).
• No decks or palpable.
• Painless.
• Appears in youth and adolescents.
• Etiology: sports with sudden stops and turns, heel strike with the ground (tennis, paddle tennis, basketball, etc.).
• Purple angiopathic traumatic origin (dermal capillaries rupture, with extravasation of red blood cells).
• Self-resolving.
• Treatment is rest.
• Differential diagnosis with acral lentiginous melanoma (usually unilateral).
10. Vesicular or Dishidrotic Tinea Pedis:
• Very itchy.
• Erythematous plaque of different sizes with abundant tense vesicles.
• When dried, it becomes crusty and scaly.
• Blisters may appear.
• The contents may become pus (pustules).
• Affects the plantar arch and the lateral surfaces of the fingers.
• Treatment: oral antifungals.
11. Interdigital Tinea Pedis or Athlete’s Foot:
• Infection by dermatophytes.
• The main predisposing factor is the use of closed shoes.
• Affects subsequent interdigital spaces, especially the 4th and flexion creases.
• Erythema in the space.
• Fissures and itching at the bottom of the fold.
• Areas of flaking and white maceration.
• Extends to the rest of the interdigital spaces, back of the fingers, pads, and foot.
• Frequently associated with tinea pedis nail and interdigital tinea pedis.
• Treatment: oral antifungals.
12. Common Wart:
Human papillomavirus types 1, 2, 3, 4, 7, 10, 26, and 28.
• Vegetations usually small and multiple, keratotic, pink, autoinoculable, and contagious.
• The virus enters through continuity solutions in the skin and mucous membranes, requiring an erosion mechanism for infection, either directly or indirectly.
• More common in children and open areas.
• Personal susceptibility exists.
• Spontaneous regression occurs over years.
• Do not penetrate the dermis; they are growths of skin that develop and tend to disappear after years.
• Often periungual.
13. Plantar Wart:
Human papillomavirus types 1, 2, 4, 60, 63, and 65.
• Contagion by indirect means (clothing, floor, etc.).
• Appears on the feet.
• Wet surfaces in bathing or swimming pools facilitate transmission.
• Minor trauma or maceration of the area is needed for papillomavirus inoculation.
• Incubation period ranges from weeks to months.
• Increased incidence in autumn.
• More common in children and youth.
• Very painful: a sign of the pitch and pinch.
• Can be single or multiple.
• A small delamination has brownish-black spots due to dilation and thrombosis of blood vessels and dermal papillae.
• In the center of the wart, no dermatoglyphics are present.
• Growth is in depth (endophytic).
• Rounded, well-defined, hard, embedded in the skin, and surrounded by a dermatological ring.
• Usually appears in pressure areas and regions of support.
14. Foveolar Keratolysis:
• Non-inflammatory corneal infection.
• Produced by Corynebacterium species.
• Appears as small crateiform depressions (punch) of 1-5 mm. They are round and surface and may extend to form a plate of different sizes.
• Appears in areas of more support and also in areas of friction such as interdigital spaces.
• Predisposition to moist heat.
• Associated with hyperhidrosis.
• Whitish elements.
• Treatment:
– Prevent maceration.
– Topical antiseptics.
– Topical antibiotics.
15. True Impetigo:
• Common in children and during summer.
• Very contagious.
• Subcutaneous ampoules.
• Throat or staphylococcal infection.
• Vesicoampullas surface are formed, leading to pustules and crusts with meliceric secretion.
• Healing occurs without scars.
• Clinical forms: giant phlyctenular impetigo, ecthyma, and blistering dactylitis.
16. Erysipelas:
• Involvement of the epidermis, dermis, and hypodermis.
• Feverish syndrome.
• Red, edematous, warm, and painful plate.
• Progressive growth in the periphery.
• Blisters on the surface.
• Satellite adenopathies.
• Involvement in adults: legs and face.
• Involvement in children: torso and face.
• Repeated outbreaks: lymphatic obstruction and lymphedema.
• Treatment with topical antiseptics, drainage of pus, and oral, topical, or parenteral antibiotics.
17. Necrobiosis Lipoidica Diabeticorum:
• Erythematous papule that slowly enlarges.
• Red outer plate and high, flattened at the center, atrophic and yellow.
• Residual atrophy and pigmentation.
• Bilateral and symmetrical.
• Appears on the legs, pretibial region, and dorsum of the feet.
• Asymptomatic. Sometimes it appears with itching and burning.
• May ulcerate. Painful.
• Can precede diabetes.
• Appears in both types of diabetes, more frequent in type I.
• More common in women aged 30 years.
• Pathogenesis involves diabetic microangiopathy, vasculitis, and collagen antibody-mediated abnormalities or degeneration.
18. Perforating Plantar Mal:
• Neuropathic ulceration.
• Sensory neuropathy.
• Punch-like appearance. Deep and painless.
• Appears on physiological or pathological support.
• Sometimes preceded by serohemorrhagic blister or hemorrhagic callus.
• Single or multiple (unilateral or bilateral).
• More common in adult males.
• Etiology: diabetes (most common), syringomyelia, leprosy, syphilis, arteritis, neuritis, etc.
• Clinical: painless ulcer and persistent non-inflammatory, anesthetic located in areas subject to friction and pressure on soles. It begins with a keratotic element, granular grayish or circumscribed in its center, forming a rounded punch ulcer. Slow-onset and progressive irregularity, especially in depth. Secondary infections with cellulitis and lymphangitis may occur. Osteomyelitis is also a possibility.
• Treatment: etiological, oral vasodilators.
• Treatment: surgical debridement, topical antiseptics, and local/systemic antibiotics, creams, healing, hydrocolloid dressings, and local care to avoid pressure and friction.
19. Classic Kaposi Sarcoma:
• More common in males (10:1), aged 50-70 years, Jewish, Mediterranean descent. Family history is not necessary, but there is a genetic component.
• Slow evolution over years. 10% mortality.
• Asymptomatic.
• Begins in the lower legs (malleoli and plantar surface).
• Bilateral.
• Macules and plaques reddish, purple, or brown nodules form later.
• Superficial desquamation.
• Can erode and ulcerate.
• MMII edema (lymphedema).
• Multifocal.
• Progression is caudocephalic (feet, legs, trunk, and upper limbs).
• Late systemic involvement (conjunctiva, oral mucosa, digestive tract, and others).
20. Nail-Patella Syndrome:
• Embryopathy with absence, reduction, or change in shape of the nail matrix.
• The severity of the defect decreases from the 1st to the 5th finger.
• Anonychia of 1 finger (most common).
• Morphology of nails: short, narrow, and fragile (dystrophic nail).
• The lunula may be lacking or triangular.
21. Paronychia:
Inflammatory process of the nail folds.
• Etiology: staphylococci, Enterobacteriaceae, and herpes viruses. Infection after trauma, punctures, onychophagia, manicure, or pedicure. Onychocryptosis can be associated.
• Clinical:
– Nail fold erythematous, edematous, and painful.
– Purulent collection exists under the fold or below the nail plate.
– Compression of the fold can cause pus to exit from the periungual groove.
– Other healing can be observed with alteration of the nail plate due to temporary damage to the nail matrix.
• Treatment: topical antiseptics and topical/oral antibiotics. Incision and drainage of purulent material to avoid damage to the matrix. If herpes is present, topical acyclovir is used.
• If chronic, it affects hands, Candida albicans, while the fold is edematous and erythematous. There is fibrosis in a crown or proximal rim, painful to pressure, and sometimes green or brown coloration of the nail plate. There is surface damage to the nail plate due to chronic pain in the matrix.
22. Koilonichia:
• Derives from the Greek word for spoon, a concave ladle.
• Nail is concave, soft, fine, but not keratinized at the edges.
• More often involves the hands.
• Pathogenesis: the distal matrix is lower than the proximal or angulation of the nail matrix secondary to connective tissue disorders.
• Types:
– Congenital: hereditary, associated with other ectodermal defects.
– Acquired or idiopathic: traumatic and occupational (work with petroleum products, acids, and alkalis), nutritional deficiency for iron, vitamins, and conditions affecting the cardiovascular, renal, thyroid systems, and dermatological conditions such as psoriasis, lichen planus, alopecia areata, or scleroderma.
23. Hjorth Pustules:
• Injuries to distal finger pads, particularly in onychopathies.
• Frequent in children younger than 10 years.
• Slight predominance in females.
• Affects fingers and toes, more common in the 1st fingers.
• Family history.
• Clinical:
– Erythema, dryness, fine flaking of the pad and periungual area.
– Absence of pustules.
– Nails thickened, distorted, dull, and sometimes with subungual dotted and transverse grooves.
– The impairment persists for months or years, usually disappearing after puberty.
– Dermatological findings: acanthosis, papillomatosis, parakeratosis, dermal inflammatory infiltrate with exocytosis, and spongiosis. Table of atypical chronic eczema or psoriasis. Minimal form of atopic dermatitis and psoriasis.
• Treatment: unsatisfactory, consisting of topical corticosteroids, emollients, and protective measures.
24. Pachyonychia:
• Congenital thickening of the nail where the nail bed is also thickened.
• Syndrome of Jadassohn-Lewandowsky (1906).
• Autosomal dominant inheritance.
• Appearance at birth or childhood, with few instances appearing late (18-20 years).
• Associated with other disorders of keratinization (palmoplantar keratoderma and follicular leukokeratosis, oral and palmar-plantar hyperhidrosis).
• There are 4 clinical types.
• Affects the entire nail.
• Nails are yellow-brown at birth.
• Progressive thickening of the nail plate.
• Nails may break (they are painful).
25. Impetigo:
• Streptococcal skin infection.
• More common in children and during summer.
• Very contagious.
• Subcorneal ampoules that break easily.
• Vesiculobullous surface forms, accompanied by pustules and scabs with purulent secretion.
• Yellow drainage is purulent material.
• Healing occurs without scarring.
• Impetiginized dermatoses occur in superinfected areas.
• Clinical forms: giant phlyctenular impetigo, estimates, and blistering distal dactylitis (affects the distal surface of the fingertip due to perionychia).
26. Leuconychia:
• A target.
• There are 3 types:
1. True (womb) may be total, subtotal, and partial. It is punctate, transverse, and longitudinal.
2. Apparent (fingernail) involves subungual tissue, with normal lamina.
3. Pseudoleuconychia: external source, or onychoschisis, onychomycosis.
27. Distal Lateral Subungual Onychomycosis:
The most common type. Appears in toenails. The etiological agents are dermatophytes (Trichophyton rubrum). The invasion begins with the distal crease and hyponychium, sometimes near the lateral sulcus. The clinical features include: thickening of the nail (distal), proximal advancement of the infection (onycholysis), and the nail becomes detached and opaque (yellowing or brown).
28. Proximal Subungual Onychomycosis:
Appears in fingernails and feet, typically in the 1st finger. The invasion begins on the dorsal surface of the proximal fold and eponychium (nail matrix-ventral surface of the nail plate). There is a whitish stain in the area of the lunula, which moves towards the free edge. Sometimes it starts in waves, creating a zebra pattern in very intense onychomadesis. In patients with AIDS, the rapid development of proximal subungual onychomycosis is a marker of disease.
29. White Surface Onychomycosis:
Almost exclusively affects toenails. Leukonychia Trichophyticus. The invasion begins on the dorsal surface of the nail. Small white macules, opaque, with irregular contours in islets. They may converge and affect the entire nail plate. The affected nail surface is rough, uneven, and crumbly.
30. Total Dystrophic Onychomycosis:
Complete dystrophy of the nail plate. It is the final stage of the progression of the above without proper treatment. The nail plate breaks up and crumbles until it disappears. The nail bed is thickened with keratotic debris from the nail. In AIDS patients, the onset is rapid, following proximal subungual onychomycosis.
31. Melanocytic Nevus:
• Melanocytic nevus of the nail matrix results in a linear longitudinal pigmentation of the lamina, brown-black color maintained.
• Can slowly increase in size and color.
• More frequent and acquired, although congenital cases exist.
• Differential diagnosis with subungual melanoma and other melanonychia.
• Treatment: in adults, surgery (removal of the nail and then the nevus) and in children with congenital cases, expectant management and regular reviews (to see if it grows or changes color) and/or surgical intervention.
32. Diabetic Dermopathy:
• Dermatosis most frequently associated with diabetes.
• No prognostic value of duration or severity.
• Macules are small, asymptomatic, round or oval, with cut edges and surface peeling.
• Evolution shows mild central depression and brown pigmentation (hemosiderin deposition).
• Etiology: microangiopathy. More common in women after age 50. Located on the external malleolus, forearm, and anterior and lateral surfaces of the legs.
33. Lichen Planus of the Nailfold:
• Affects 10% of patients.
• Can affect one, several, or all nails.
• Appears alone or with cutaneous or mucosal lesions.
• The nail presents with longitudinal grooves, longitudinal fissuring, thinning of the lamina, taquioniquia, onychorrhexis, and onychomadesis.
• The prognosis depends on the degree of impact on the matrix, the intensity of inflammation, and residual scarring. Focal or complete destruction of the matrix.
34. Yellow Nail Syndrome:
• Due to respiratory disorders.
• Related to nail disorders and respiratory lymphedema (pleural effusions, sinusitis, bronchitis, and bronchiectasis).
• Lymphedema (ankle edema), also in the hands and face. Atresia, hypoplasia, and varicose dilation of lymphatic vessels.
• Nails grow slowly and are hypercurved, thickened, and yellowish throughout the nail plate.
• The cuticles are weak and may have onycholysis.
• Affects all nails and toes (all 20 nails).
• Treatment: oral vitamin E and intralesional corticosteroids.
35. Glomus Tumor:
• Vascular tumor, circumscribed, hemispheric, smooth, pink or violet, spontaneously painful to pressure and temperature changes.
• Typical location is subungual, giving a bluish tone to the nail plate.
• As it grows, it can break the nail plate.
• MRI is recommended for diagnosis.
• Treatment: surgical removal.
• Surrounded by a dense connective capsule.
36. Demonstrations of Foot Infections:
A) Syphilis: syphilids palmar-plantar (nails syphilitic) are erythematous papules with a yellowish color, sometimes surrounded by scaling. They are indicative of syphilis (diagnostic). When pressed, they cause pain, and the disc penetrates the skin thickness.
B) Reiter’s Syndrome: causes of sacroiliac arthritis in the lower limbs, leading to blennorrhagic keratoderma, crusty, scaly, and circinate. Causes onychodystrophies.
37. Diabetic Bullous Dermatitis:
• Appears in longstanding diabetic patients with multiple complications.
• Usually asymptomatic but sometimes presents with mild pain.
• Located on the back of the foot, ankles, thighs, and legs.
• May recur.
• Higher proportion in males (2:1).
• Age between 17-84 years.
• Microangiopathy.
• Types:
1. Spontaneous and non-scarring: clear, sterile, superficial, and appears on non-sore skin. Heals without residual scarring.
2. Hemorrhagic and scarring: deeper, bleeding, with dermo-epidermal separation, and tend to cause skin necrosis and residual scars.
38. Pyogenic Granulomas:
• Small pink or yellow lesions.
• Appear on the lateral and posterior heel.
• Serious herniations through connective trabeculae.
• Are perceptible and disappear when lying down.
• Can be painful.
• Treatment: rest.
39. Carcinoma Warts:
• The least aggressive form of squamous cell carcinoma.
• Etiology: different types of papillomavirus.
• Types:
1. Florid oral papillomatosis.
2. Giant condylomatosis.
3. Cuniculatum carcinoma.
• Cuniculatum carcinoma is a form of verrucous carcinoma of the foot. The prognosis is generally good, and growth is slow. It is well-circumscribed and has a papillomatous surface. Subsequent serological tests are needed for males over age 50. It is caused by papillomavirus types 1, 4, 6, 11, 16, and 18. Called cuniculatum because it resembles a rabbit with burrows when viewed under a microscope. Exophytic masses are found on the soles of the feet or fingers. It can also exhibit endophytic growth.
40. Skin Melanoma:
• Severe skin neoplasm.
• Highly invasive and metastatic.
• Dominance in U.S. Caucasians, Australians, or Europeans.
• Cases are doubling every 10-15 years.
• Most common cancer in white men aged 35-44 years.
• In Spain, cases have increased tenfold in the last 20 years.
• Etiopathogenic factors:
– Environmental: sun exposure, sunburn, UVA rays, etc.
– Personal factors: white skin, fair skin, pigmented precursor lesions (atypical nevi), congenital factors, etc.
– Other factors: continuous trauma, etc. (acral lentiginous melanoma).
• Clinical: blackish-brown macule with irregular contours. Irregular peripheral growth with very dark areas and some very light, bluish, or reddish areas, which can reach a relatively large size. The surface can be keratotic, leading to ulceration and bleeding in later stages. It may be amelanotic in 20% of cases.
41. Physical Therapeutics in Dermatology:
1. Radiotherapy: used in benign dermatoses after other treatments fail. It is effective for squamous cell carcinomas and sarcomas but not in melanoma and basal cell carcinoma.
2. Dermabrasion: scraping and smoothing. It does not reach the hypodermis. It is done with a little depression around scars, tattoos, and extensive benign lesions.
3. Electrosurgery: using alternating current for cutting, coagulation, and desiccation.
4. Cryosurgery: application of intense cold (e.g., liquid nitrogen) does not require anesthesia. It is done on an outpatient basis. Fast and economical with satisfactory cosmetic results. Disadvantages: it is painful and cannot be used for anatomical pathology studies.
5. Phototherapy: using UV (short, medium, or long).
6. Laser therapy: monochromatic light energy. There are medical lasers (anti-inflammatory and healing) and surgical lasers (destroy skin by heat).
7. Iontophoresis: using alternating electrical current with contact electrodes allows for drug administration. Not used in patients with pacemakers and metal prostheses, with caution in pregnancy and arrhythmias. Side effects: paresthesia, erythema, vesiculation, and small burns.
42. Subungual Melanoma:
• Represents 2-3% of white consultations.
• Late diagnosis.
• Poor prognosis.
• Very aggressive, with a strong tendency for early lymph node metastases.
• Presents with the same frequency in hands and feet, more common in the 1st finger.
• Etiology: trauma.
• Clinical: macula/s linear blackened, irregular with progressive and rapid growth (longitudinal melanonychia). The entire nail can turn black. Invades across the bed and the proximal and lateral folds (Hutchinson’s sign, melanic whitlow). Distortion or partial or complete destruction of the nail plate. There may be pigmentation of the pad. A vegetans element is a blue-green hue. Ulceration and bleeding may occur.
• Difficult to distinguish from subungual nevus in early stages.
• Possibility of malignant transformation of melanocytic nevi into melanoma.
• Amelanotic subungual melanoma is more difficult to diagnose and has a worse prognosis, presenting as paronychia, with a vegetans element, bleeding, uplifting, and destruction of the nail plate.
• Treatment: surgical excision with safety margins, complete amputation at the metatarsophalangeal or partial distal interphalangeal level. Treatment includes interferon and adjuvant chemotherapy for metastases.
43. Factors Affecting Nail Growth Rate:
1. Physiological factors:
– Fast: hand fingers, long fingers, dominant hand, daytime, pregnancy, youth, summer heat, male.
– Slow: toe fingers, short fingers, non-dominant hand, nighttime, first days of life, senescence, cold winter, female.
2. Pathological factors:
– Fast: microtrauma, onychophagia, onycholysis, psoriasis, periungual inflammation, arteriovenous shunts, hyperthyroidism.
– Slow: immobilization, fever, systemic diseases, food shortages, immunosuppressants, hypothyroidism, and yellow nail syndrome.
44. Functions of the Nails:
1. Sensory: nerve endings provide sensation.
2. Oppressive: grip objects.
3. Protective: safeguard vascular and nerve structures in the nail bed. Prevents heel lift.
4. Scratching: mechanism of defense against external aggression, used for itching.
5. Cosmetic: well-groomed nails for decoration.
45. Phases of Nail Embryology:
1. Plate phase.
2. Fibrillation phase.
3. Granular phase.
4. Flaky phase.
5. Final nail phase.
46. The Foot in Leprosy:
• M. leprae.
• Leprosy unspecified, tuberculoid leprosy, lepromatous leprosy, and borderline leprosy.
• M. leprae has a preference for affecting peripheral parts and acral areas. The foot is one of its favorites.
• Even after curing, significant deformities and sequelae can occur.
• Lesions include macules, nodules, infiltrations, and ulcers.
• Can cause plantar mal perforans, neuronal injury (sensory disturbances, motor), and musculoskeletal injuries (most common in late diagnosis).
47. Pustular Acrodermatitis Continua of Hallopeau:
• Appears in the distal finger pads.
• Outbreaks of erythematous scaly lesions and pustules.
• Can move proximally.
• Causes damage to the nail matrix with significant onychodystrophies, which can lead to anonychia.
• Atrophy of the distal phalanx.
• Chronic course.
• Treatment:
– General: Omedas.
– Local: keratolytics (salicylic acid 5-20%, 10-30% urea), retinoids (retinoic acid), corticosteroids, vitamin D derivatives (calcipotriene).
– Systemic: phototherapy, heliotherapy, UVB phototherapy, retinoids, cytostatics, immunosuppressants, steroids, and biologic therapies.
48. Plantar Keratosis Foveolar-Sulcatum:
49. Tumors:
50. Acute Paronychia:
• Etiology:
– Staphylococci
– Streptococci
– Enterobacteriaceae
– Herpes virus (herpetic whitlow)
• Clinical:
– Nail fold erythematous, edematous, and painful.
– Purulent collection under the fold and even under the nail plate.
– Compression of the fold can cause pus to exit from the periungual groove.
– Trauma: punctures, onychophagia, manicure, or pedicure.
– In feet, associated with onychocryptosis.
• Healing can show other changes in the nail plate due to temporary damage to the nail matrix. Herpes simplex virus can cause herpetic whitlow.
• Treatment:
– Topical antiseptics.
– Topical antibiotics.
– Oral antibiotics.
– Incision and drainage of purulent material to avoid permanent damage to the nail matrix.
– Herpetic whitlow: oral or topical acyclovir.
51. Reiter’s Syndrome:
• Clinical and histological features are typical of psoriasiform lesions.
• The onychopathies are also of the psoriasis type.
• More intense in HIV patients.
52. Psoriasis of the Nailfold:
• Treatment:
– Unsatisfactory.
– Photochemotherapy.
– Oral cyclosporine or methotrexate.
– Topical: corticosteroids, retinoids, vitamin D derivatives, and topical immunomodulators.
53. Subungual Hematoma:
Nail lesions are more frequent in acute nail treatments and are very painful. Also occurs due to repeated microtrauma, in this case, painful. Less common in bleeding disorders. It can affect one or more fingers. The clinical features will depend on the location and intensity of the causal trauma; if on the matrix, it will take several days to appear, while if on the nail bed, it is observed immediately. Variation of color occurs. In large bruises, there is a possibility of underlying phalanx fractures, which should be ruled out radiographically. With nail growth, the hematoma may resolve.