Summary
This article covers various dermatological disorders, including cutaneous mastocytosis, miliaria, dyshidrotic eczema, livedo reticularis, and albinism.
Miliaria
- Definition: transient, papular exanthem following exposure to heat
- Etiology: blockage of the eccrine sweat ducts in hot and/or humid environments
- Localization: : mainly on the trunk, neck, and intertriginous areas
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Treatment
- General measures to reduce sweating: wearing light, breathable fabrics, keeping the patient in a cool environment, removing occlusive bandages, etc.
- Topical steroids; (hydrocortisone, triamcinolone), topical antibiotics for pustular eruptions (clindamycin, erythromycin)
Types of miliaria | |||
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Miliaria crystallina | Miliaria rubra | Miliaria profunda | |
Epidemiology |
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Level of sweat duct blockage |
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Gianotti-Crosti syndrome
- Definition: maculopapular exanthem associated with viral infections, especially hepatitis B and Epstein-Barr virus (EBV)
- Epidemiology: age of onset is < 5 years [2]
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Clinical features
- Affects the face, buttocks, and extensor surfaces of the extremities
- Pruritus may occur
- Self-limiting, lasting between 10 days and 6 months [3]
- Treatment: symptomatic
Dyshidrotic eczema
- Definition: a condition characterized by a recurrent, acute blistering eczema of the palms and/or soles
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Etiology
- Unknown (believed to be multifactorial)
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Risk factors include:
- Atopic dermatitis
- Irritant contact dermatitis
- Allergic contact dermatitis (e.g., nickel, cobalt, balsam of Peru, perfumes)
- Dermatophyte infections
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Clinical features
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Acute, recurrent episodes of pruritic vesicular/bullous eruptions on the palms, lateral aspects of the fingers, and/or soles
- Warm weather exacerbates symptoms.
- The lesions are usually multiple and deep-seated.
- Severe cases include dystrophic nail changes (e.g., color changes, ridge formation)
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Acute, recurrent episodes of pruritic vesicular/bullous eruptions on the palms, lateral aspects of the fingers, and/or soles
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Diagnostics
- Usually a clinical diagnosis.
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Skin biopsy
- To rule out differential diagnoses (e.g., psoriasis) or in case of poor response to treatment.
- Findings include intraepidermal spongiotic vesicles/bullae without involvement of the eccrine sweat glands.
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Treatment
- Avoid triggers (e.g., allergens and irritants such as metals, perfumes, or cigarette smoking)
- Appropriate skin care (i.e., wash hands with lukewarm water and soap-free cleanser, apply emollients after drying hands adequately)
- Topical corticosteroids for mild cases that do not respond to general measures
- Oral corticosteroids for severe cases
- Consider adding PUVA or UVA treatment for patients with refractory disease.
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Complications
- Chronic hand dermatitis: lichenification, scaling, fissured patches and plaques
- Secondary infection (e.g., Staphylococcus aureus)
Erythema ab igne
- Description: reticular erythema with telangiectasias
- Etiology: paralysis of the deep vascular plexus of the skin caused due to chronic heat application (e.g., infrared radiation, hot water bottles)
- Pathophysiology: direct skin application of heat for extended periods of time → direct heat triggers increased melanin production → marbled, brownish hyperpigmentation
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Treatment [4]
- Discontinue offending heat source
- The condition usually resolves within months to years,
- Permanent hyperpigmentation or scarring may occur: can be treated with topical tretinoin or hydroquinone
- Topical 5-fluorouracil in the case of epithelial atypia
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Complications [4]
- Squamous cell carcinoma
- Merkel cell carcinoma: a rare, rapidly progressive neuroendocrine neoplasm that typically manifests as a painless, firm, nontender, red-blue nodule on the head or neck
Pitted keratolysis (keratoma plantare sulcatum)
- Definition: superficial bacterial skin infection with pit-like corneal defects on the soles of the feet accompanied by malodor and a burning sensation
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Epidemiology
- Occurs worldwide (especially in athletes, industrial workers, and soldiers)
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Risk factors include:
- Hot, humid weather
- Occlusive footwear
- Hyperhidrosis
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Etiology
- Caused by maceration and various bacteria
- Most often occurs in association with insufficiently breathable footwear
- Clinical features: bilateral and multifocal cerebriform skin maceration and superficial erosions
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Treatment [5]
- Regular changing of footwear and socks
- Topical antibiotics (e.g., erythromycin, clindamycin)
- Possibly botulinum toxin or iontophoresis to reduce local sweating
Localized lipodystrophy
- Description: localized degeneration of subcutaneous adipose tissue
- Etiology: iatrogenic (secondary to subcutaneous injections), certain drugs (e.g., ARVT), pressure-induced, or idiopathic
- Treatment: depends on the underlying cause
SAPHO syndrome
- Description: a rheumatological, spondylarthritic disease with simultaneous occurrence of synovitis, acne, pustulosis, hyperostosis, and osteitis
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Clinical features
- Skin: acne, palmoplantar pustulosis
- Musculoskeletal: synovitis, hyperostosis (particularly of the sternoclavicular joint, spine, and/or pelvis), and chronic recurrent osteitis
- Etiology: unknown
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Diagnostics
- Mainly a clinical diagnosis
- Imaging
- X-ray: evidence of hyperostosis
- Scintigraphy: enhancement in affected bones and joints
- MRI: visible inflammatory reaction (osteitis)
- Treatment: primarily symptomatic
Livedo reticularis
Types of livedo reticularis [6] | ||
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Physiological livedo (idiopathic livedo) | Pathological livedo (livedo racemosa) | |
Definition |
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Epidemiology/etiology |
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Pathophysiology |
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Clinical features |
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Treatment |
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Prognosis |
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Livedo reticularis that does not regress after application of warmth is indicative of an underlying vascular disease and requires treatment.
Albinism
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Definition: : congenital disorders of melanin synthesis resulting in hypopigmentation
- Partial albinism: a genetic condition characterized by the partial absence of melanin pigment from melanosomes in the body due to defects in the biosynthesis of melanin
- Total albinism: a genetic condition characterized by the total absence of melanin pigment from melanosomes in the body due to defects in the biosynthesis of melanin
- Epidemiology
- Classification
- Pathophysiology: dysfunctional tyrosinase activity or impaired transport of tyrosine and/or melanin → decreased or absent melanin production (melanocyte levels are normal)
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Clinical features
- Eyes
- Translucent, hypopigmented blue, gray, or green irises
- Photophobia, decreased visual acuity
- Strabismus, nystagmus, amblyopia
- Abnormalities of the optic nerve (e.g., hypoplasia, abnormal crossing of optic fibers at the optic chiasm)
- Skin and hair: milky white color, photosensitivity, sunburns
- Associated with increased risk of skin cancer
- Eyes
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Treatment: only supportive treatment, no curative treatment available
- Treatment of strabismus: eye-patching
- Avoidance of direct exposure to UV light and regular screening for skin cancer
- Wearing (prescription) sunglasses
- Nitisinone : used for the treatment of hereditary tyrosinemia type 1
Waardenburg syndrome
- Definition: a congenital pigmentation disorder due to abnormal migration of melanocytes during embryogenesis
- Etiology: an autosomal dominant inherited disorder
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Clinical features
- Patchy depigmentation of the hair and skin (e.g., poliosis)
- Pale blue eyes or heterochromia iridum
- Broad nasal root
- Congenital hearing loss
- Cleft lip and cleft palate
- Neural tube defects
- Associated with Hirschsprung disease
- Treatment: only supportive treatment, no curative treatment available
Angiosarcoma
- Definition: a rare, very aggressive vascular malignancy, arising from endothelial cells of blood or lymphatic vessels [7]
- Epidemiology: peak incidence age > 70 years [7]
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Etiology [7]
- Radiation (e.g., radiation therapy)
- Chronic lymphedema: especially in postmastectomy lymph node resection
- Chemicals: Vinyl chloride and arsenic are implicated in hepatic angiosarcoma.
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Clinical features [8][9]
- Location
- More common in sun-exposed areas
- Usually occur on the head, neck, and breast
- May involve the internal organs (e.g., hepatic angiosarcoma)
- Lesion
- Blue/purple-colored with a bruise-like appearance
- Later stage: hemorrhage or ulceration
- High variability in appearance
- Location
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Treatment [9]
- Complete resection with wide margins
- Resection may be complicated by the aggressive course of the disease and delayed diagnosis.
Tattoo-associated skin reactions
- Definition: skin reactions associated with the needle trauma caused by tattooing or the inks involved
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Types
- Infection transmitted by needle or acquired after tattooing through damaged skin (e.g., impetigo, erysipelas)
- Eczematous hypersensitivity reactions to tattoo ink (e.g., allergic contact dermatitis, photoallergic dermatitis)
- New skin disease (e.g., psoriasis, eczema, vitiligo)
- MRI burn due to tattoo ink containing metals (e.g., mercury, iron)
- Skin cancer due to carcinogenic substances in tattooing ink
- Clinical features, diagnosis, and treatment: according to diagnosis and symptoms (e.g., antibiotic treatment of erysipelas)
Hyperhidrosis
- Definition: a condition of localized or generalized excessive sweating
- Epidemiology: estimated to affect ∼ 5% in the US [10]
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Etiology
- Primary focal hyperhidrosis
- Secondary hyperhidrosis (e.g., due to hyperthyroidism, malignancy, obesity, or adverse effects of medication)
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Clinical features: excessive sweating that interferes with activities of daily living, frequent skin infections (e.g., tinea pedis)
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Primary focal hyperhidrosis
- Usually localized (e.g., underarms, forehead)
- Both sides of the body are affected.
- No sweating during sleep; sweating begins immediately after waking up.
- Secondary hyperhidrosis: generalized, may occur during sleep
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Primary focal hyperhidrosis
- Diagnostics: clinical diagnosis
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Treatment
- Antiperspirants (over-the-counter or prescription)
- Iontophoresis
- Anticholinergics
- Botulinum toxin injections
- Surgery (surgical removal of sweat glands or sympathectomy)
Embolia cutis medicamentosa
- Definition: An iatrogenic skin lesion caused by accidental injection of a drug into an artery [11][13][14]
- Pathophysiology: embolic vessel occlusion and reflexive vasospasm → skin necrosis
- Symptoms
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Treatment
- No specific treatment exists.
- In small lesions, conservative treatment with analgesics, topical antibiotics, and glucocorticoids can be used.
- In extensive lesions, surgical debridement can be required.
Cutaneous granulomas
Cutaneous granulomas are a group of conditions characterized by a chronic inflammatory skin response to a variety of stimuli, including metabolites, foreign bodies, and infection. For more information on the etiology, pathophysiology, and pathology of these conditions, see “Granulomatous inflammation.” [15]
Noninfectious cutaneous granulomas
Noninfectious cutaneous granulomas are often manifestations of systemic diseases, including diabetes, rheumatoid arthritis, and sarcoidosis.
Granuloma annulare
- Definition: a benign, palpable, ring-shaped nodule of unclear etiology that most commonly manifests on the extremities (especially the dorsal hands and feet)
- Epidemiology [16]
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Classification [17]
- Localized
- Generalized (sparing the head, neck, palms, and soles)
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Clinical features
- Varies from skin-colored to violaceous
- Lesions may appear hypopigmented or hyperpigmented in darker skin tones.
- Pruritus (associated with generalized granuloma annulare)
- Differential diagnosis: See “Overview of annular skin lesions” for details.
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Treatment
- Localized disease typically resolves without treatment; treatment is recommended according to patient preferences for cosmetic reasons, in persistent pruritus, or if prognosis is uncertain.
- Generalized granuloma annulare is more likely than localized lesions to require systemic therapy.
- First-line: topical corticosteroids (e.g., clobetasol propionate)
- Alternatives: intralesional corticosteroid injection (e.g., triamcinolone acetonide), calcineurin inhibitors (e.g., tacrolimus ointment), systemic steroid-sparing therapy (e.g., hydroxychloroquine, isotretinoin)
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Prognosis [18]
- Localized: self-limiting
- Generalized: chronic or relapsing
Necrobiosis lipoidica [19]
- Definition: a rare, chronic granulomatous disease of the skin associated with diabetes mellitus
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Epidemiology [20]
- Approx. 60% of patients with necrobiosis lipoidica have diabetes mellitus.
- ♀ > ♂
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Clinical features
- Usually asymptomatic
- Common sites: pretibial region
- Initially, a reddish-brown papule that progresses to a yellow-brown papule or plaque with visible telangiectasias
- Ulceration of the lesion may also occur following minor trauma
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Histopathology: necrobiotic palisading granuloma
- Lymphohistiocytic infiltration with plasma cells, foam cells, and giant cells
- Wall thickening and occlusion of small blood vessels
- Destruction of collagen fibers in the entire corium
- Treatment: Corticosteroids may be effective (e.g., intralesional corticosteroid injections)
Rheumatoid nodules
- Definition: inflammatory cutaneous or subcutaneous lesions found primarily at pressure points (e.g., extensor side of the forearm, bony prominences)
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Epidemiology [20]
- Most common extraarticular manifestation of rheumatoid arthritis (RA)
- Associated with seropositive rheumatoid arthritis and more severe joint involvement than in individuals with no nodules [21]
- Clinical features: nontender, firm, subcutaneous nodules
- Histopathology: central necrosis with surrounding palisading histiocytes and granulomatous tissue [20]
- Treatment: intralesional corticosteroid injection or excision only required if the nodule causes pain or impairs movement
- For more information, see “Rheumatoid arthritis.”
Lupus pernio
- Definition: a pathognomonic manifestation of cutaneous sarcoidosis appearing as violaceous plaques on areas commonly exposed to cold (e.g., nose, cheeks, ears)
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Associations [15]
- Sarcoidosis of the lungs (approx. 75%)
- Sarcoidosis of the upper respiratory tract (approx. 50%)
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Clinical features
- Extensive, indurated plaques that tend to scar
- Distribution similar to the butterfly rash seen in systemic lupus erythematosus
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Treatment [22]
- First-line: intralesional corticosteroid injection (e.g., triamcinolone acetonide)
- Second-line: systemic glucocorticosteroids (e.g., prednisolone), steroid-sparing therapy (e.g., antimalarials, methotrexate, tetracycline)
Foreign body granulomas
- Definition: noncaseating granulomatous inflammation of the cutaneous or subcutaneous tissues in response to the introduction of foreign materials
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Classification [23]
- Endogenous: due to endogenous material (e.g., hair fragments, cholesterol crystals, calcifications) identified by the immune system as foreign
- Exogenous: due to introduction of exogenous material (e.g., cosmetic fillers, sutures, fish spines)
- Stages
- Diagnostics: ultrasound, biopsy [24]
Infectious cutaneous granulomas
- Definition: any granuloma caused by a pathogen
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Examples
- Cutaneous tuberculosis: granulomatous inflammation with caseous necrosis caused by Mycobacterium tuberculosis
- Tuberculoid leprosy: hyperesthetic, hairless, skin lesions caused by Mycobacterium leprae
- Cutaneous leishmaniasis: the most common form of leishmaniasis, characterized by reddish macules and papules that may progress to ulcers