10th July 2023

Miscellaneous

Skin in Systemic Disease

Respiratory

Sarcoidosis

Skin manifestations are seen in a quarter of those with systemic sarcoid, sometimes in the absence of systemic disease. Cutaneous manifestations include erythema nodosum, lupus pernio (see image below), scar sarcoid and scarring alopecia.

Lupus pernio

Image Source: Wikimedia Commons (2011). Lupus pernio 01, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Lupus_pernio_01.jpg (Accessed on: 16 July 2022).

Tuberculosis

Tuberculosis is associated with scrofuloderma (breakdown of skin overlying TB focus), lupus vulgaris (50%), verrucosa cutis, scarring alopecia, and gumma.

Metabolic Disorders

The Porphyrias

The classic skin manifestations of porphyrias are blister formation, photosensitivity, scarring with milia and hypertrichosis.

Table 1: Types of porphyrias

Diabetes

Diabetes can often present with a wide range of cutaneous signs, such as necrobiosis lipoidica, granuloma annulare, diabetic rubeosis, diabetic dermopathy, candidiasis, vitiligo, and neuropathic foot ulcers.

• Diabetic dermopathy presents with dark red papules that eventually become atrophic and is associated with a long duration of diabetes mellitus.
• Necrobiosis lipoidica (waxy yellow lesions) mainly affects the shins and is associated with telangiectasia
• Granuloma annulare present as papules with central depression.

Acanthosis nigricans

Often described as dark, thick, velvety patches that present in skin folds, namely the underarms, neck, and groin. It often indicates an underlying health concern, such as internal malignancy, acromegaly, Cushing syndrome, obesity, insulin resistant diabetes or hypothyroidism. It can also be seen in those that take the oral contraceptive pill. Acanthosis nigricans can be familial.

Thyroid disease

Table 2: Thyroid disease and its cutaneous manifestations

Rheumatology

Rheumatoid arthritis

Specific cutaneous changes include:

• Rheumatoid nodules
• Vasculitis causing changes such as nail fold infarcts and ulcers
• Pyoderma gangrenosum

Dermatomyositis 

Skin manifestations include the classic heliotrope rash around the eyes, Gottron papules (red plaques on the extensor surfaces of finger joints), Gottron sign (erythema over knees and elbows), dilated nail fold capillaries, ragged cuticles, and nail fold infarcts. Please note that when a patient presents with dermatomyositis, this warrants an investigation for an underlying malignancy, namely bronchial, breast and ovarian.

Lupus Erythematosus

• Discoid lupus erythematosus is associated with scaly erythematous plaques with follicular plugging on sun-exposed areas of the skin. They tend to heal with scarring.
• Systemic lupus erythematosus (SLE) is commonly associated with cutaneous manifestations such as a malar rash (facial butterfly rash with purple hue), photosensitivity, vasculitis, Raynaud’s phenomenon, alopecia, and oropharyngeal ulceration.

Paraneoplastic Cutaneous Manifestations

Dermatological signs can be seen in various types of malignancy, with some being more common in certain types of neoplasia.

Table 3: Types of cutaneous manifestations in internal malignancies

Pyoderma Gangrenosum (PG)

PG presents clinically as painful, deep red necrotic ulcerating lesions with a violaceous border that mainly affects the lower extremities. Underlying medical disease is noted in approximately 50% of these patients, namely inflammatory bowel disease, rheumatoid arthritis, SLE and myeloid leukaemia. PG can characteristically cause peristomal complications in inflammatory bowel disease. Treatment involves oral steroid supplementation. PG is not typically associated with diabetes.

Table 4: Medical conditions associated with PG

Pyoderma gangrenosum 

Image Source: Wikimedia Commons (2008). Crohnie Pyoderma gangrenosum, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Crohnie_Pyoderma_gangrenosum.jpg (Accessed on: 16 July 2022).

Gastrointestinal disorders

Hepatology

Table 5: Cutaneous manifestations of liver disease

Malnutrition

Please refer to the topic ‘Nutrition’ in the Gastroenterology section for more detail.

Inherited Skin Disease

There are a multitude of genetic conditions that have associated skin manifestations (see table).

Table 6: Inherited conditions with dermatological manifestations.

Hair and Nail Disorders

Hair Disorders

Hypertrichosis and Hirsutism

Excessive hair growth can be androgen-independent (hypertrichosis) or androgen-dependent (hirsutism – excess hair growth in a male pattern that occurs in women).

Table 7: Causes of hypertrichosis and hirsutism

Treatment options can include physical hair removal or medication such as the combined oral contraceptive pill (that contains anti-androgenic cyproterone acetate), spironolactone, finasteride and topical eflornithine.

Scarring alopecia

Scarring alopecia is hair loss with destruction of hair follicles. Causes include ichthyosis, tuberculosis, syphilis, burns, radiotherapy, kerion, lichen planus, discoid lupus, morphoea, sarcoidosis and cicatricial pemphigoid.

Non scarring alopecia

Non scarring alopecia is hair loss with preservation of hair follicles. Alopecia areata often presents as the classic ‘exclamation mark’ hair. It is often associated with nail dystrophy, cataracts, and other autoimmune diseases such as vitiligo, autoimmune thyroid disease, pernicious anaemia, and Addison’s disease. 50% of patients have hair growth within 1 year. First line treatment includes topical corticosteroids.

Other causes of non-scarring alopecia include male pattern (androgenic) alopecia, hypopituitary state, thyroid disease, hypoparathyroidism, pregnancy, iron deficiency anaemia, telogen effluvium, trichotillomania, and chronic illness. Medications that can lead to non-scarring alopecia include retinoids, anticoagulants, anti-mitotic agents, oral contraceptive pill, carbimazole, thiouracil and lithium.

Trichotillomania

Also known as a hair pulling disorder leading to alopecia. It affects 4% of the general population and is more commonly seen in females. It is associated with obsessive-compulsive disorder and is triggered by stress and anxiety. There have been studies that have identified a genetic linkage.

Nail Disorders

Nail changes associated with skin disorders

• Psoriasis: nail changes include onycholysis, nail pitting, subungual hyperkeratosis, pustule, and occasional loss of the nail.
• Fungal: fungal infection signs include thickening of the nail, onycholysis and discolouration. Treatment: oral terbinafine.
• Bacterial: usually secondary to staphylococcal infections. Pseudomonas infections give the nail a green/black discolouration and are often treated with oral ciprofloxacin.
• Lichen planus: nail changes occur in up to 10% of patients. Changes include thinning of the nail plate and longitudinal linear depressions/ ridging. Occasionally patients present with pterygium.
• Alopecia areata: pitting, thickening, and ridging of the nail – known as sandpaper nail
• Dermatitis: coarse pits, cross ridging and onycholysis may be seen

Nail changes associated with systemic disease

• Koilonychia: thin, brittle spoon shaped/concave nails. Associated with iron deficiency anaemia.

Koilonychia 

Image Source: Wikimedia Commons (2018). Koilonychia iron deficiency anemia, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Koilonychia_iron_deficiency_anemia.jpg (Accessed on: 16 July 2022).

• Yellow nail syndrome: excessively curved, yellow nails. Often associated with recurrent pleural effusions, chronic bronchitis, bronchiectasis, congenital lymphedema, nephrotic syndrome, and hypothyroidism.
• Nail-patella syndrome: loss of the ulnar half of the nail, usually affecting the thumbnail. Associated with small patellae, bony spines over the posterior iliac crests, renal abnormalities, over extension of the joints and laxity of the skin.
• Beau’s lines: transverse depressions in the nail due to temporary arrest in growth. They usually occur after illness or infection.

Beau’s Lines 

Image Source: Wikimedia Commons (2014). Beau’s line on left, middle fingernail, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Beau%27s_line_on_left,_middle_fingernail.jpg (Accessed on: 16 July 2022).

Onycholysis

Onycholysis is when the nail plate separates/lifts away from the underlying nail bed. Causes include dermatological (psoriasis, dermatitis), infective (fungal), vascular (Raynaud’s), metabolic (hypo/euthyroid), and traumatic (such as through regular manicures).

Sebaceous and Sweat Gland Disorders

Please refer to the Dermatology topic ‘Inflammatory Disorders’, where the topics acne vulgaris and acne rosacea are covered.

Hyperhidrosis 

Hyperhidrosis is excessive sweating. Sweat is produced by the eccrine glands of the skin. There are two types of sweat glands – apocrine (open into hair follicles) and eccrine (widely distributed, more serous fluid expulsion). A dysfunction in the eccrine glands often leads to hyperhidrosis Causes include climate changes, anxiety, spicy food, stroke, malignancy, diabetes, menopause, hyperthyroidism, alcohol, caffeine and many more.

Treatment options:

First line: topical aluminium chloride

Iontophoresis

Botulinum toxin – axilla

Endoscopic transthoracic sympathectomy

Anhidrosis 

Anhidrosis or lack of sweating can be associated with systemic diseases such as Sjogren’s syndrome, Fabry’s disease, burns, psoriasis and disorders of the central nervous system.

Hidradenitis Suppurativa (HS)

A skin condition that primarily affects the apocrine glands of the groin and axillae. It is characterised by persistent or recurrent boil-like nodules and abscesses that culminate in a purulent discharge, sinuses, and scarring. Risk factors include obesity, cigarette smoking, family history (30%), African ethnicity, Crohn’s disease, and medications such as lithium and sirolimus. The lesions often present as comedones and painful papules that eventually progress into draining sinuses and scarring. Complications include pyogenic granulomas, secondary infections, lymphoedema and squamous cell carcinomas. Management involves lifestyle measures. Medical options include topical benzoyl peroxide, topical clindamycin, anti-androgen therapies, systemic steroids, ciclosporins and surgical drainage. The treatment of HS can often be challenging for clinicians and a multidisciplinary team approach is often needed.