Patients may develop contact allergy to topical agents.
Asteatotic eczema
Often seen in elderly individuals, caused by skin dryness and excessive washing (soap, abrasive brushes, sauna).
The skin dries particularly in the winter, and the use of basic topical ointments as well as moderately potent to potent glucocorticoid creams is indicated.
The condition usually improves spontaneously in the summer.
Atopic dermatitis
It is possible for atopic dermatitis to occur on the legs, but it usually is also present in other typical skin areas.
The key to correct diagnosis lies within the patient's history.
The most common areas involved are the extensor aspects of the extremities and the back. Occurs typically on the legs and often also on the arms as itchy, round and scaly patches (picture 4).
May worsen during winters and because of the skin becoming dry.
Successful management requires the use of a potent glucocorticoid cream for an adequately long time (2-4 weeks).
Allergic contact dermatitis on the legs may be caused by topical agents (picture 5).
Erythema, which may become widespread, will develop around the original site of dermatitis Allergic Contact Dermatitis. The patient often states that the cream never felt quite right.
It is also possible to develop contact allergy to glucocorticoid creams.
Neurodermatitis (lichen simplex chronicus)
Neurodermatitis may appear without a distinct preceding cause, but often it is a complication of an existing itchy rash, e.g. atopic dermatitis.
The condition is characterised by a cycle of itching and scratching, which may become chronic and recur easily.
The ankle and lower leg are typical sites for neurodermatitis (pictures 67).
Group III glucocorticoid cream or solution is spread over the rash, which is then covered with a hydrocolloid dressing (e.g. Duoderm® ). The occlusive dressing is changed every 2-4 days 2-3 times.
Prurigo nodularis
Prurigo nodularis is considered to be a widespread version of neurodermatitis.
The condition is based on a cycle of itching and scratching and often becomes chronic.
Raised nodules of 0.5-1 cm in diameter, often with a crusted top, develop on the pruritic site secondary to scratching and picking at the skin (picture 8).
Pruritic nodules most commonly occur on the limbs (e.g. on the legs) and the trunk.
The aetiology is unknown, but the most common site for pigmented purpuric dermatosis is the legs (pictures 1314).
The condition is benign and mainly constitutes a cosmetic problem.
Several subtypes have been described, based on the appearance of the condition, for example, purpura pigmentosa progressiva (Schamberg disease) and lichen aureus (pictures 1516).
Purpura generally refers to pin-prick or small patchy bleeding under the skin.
Purpura is also encountered in conditions affecting blood vessels (vasculitis) or blood platelets (thrombocytopenia), but it is rare in coagulopathies Easy Bruising, Petechiae and Ecchymoses.
Other leg rashes
Nodular diseases of the leg form a very mixed group as regards aetiology, and diagnosis often requires histologic confirmation.
Granuloma annulare is a skin condition usually encountered in school-aged children and in young adults. The majority of patients are female. The predominant sites in the lower extremities are the ankles (picture 19) and the metatarsal areas. Skin lesions on the legs may be more extensive.
Necrobiosis lipoidica (pictures 202122) usually occurs on the front aspect of the legs as sharply defined ring-shaped plaques with an atrophic centre, which may ulcerate. The aetiology is unknown but may be associated with diabetes.
In Borrelia infection Lyme Borreliosis (LB), erythema migrans may occur on a leg (picture 23).
Consultation
Prolonged and treatment resistant leg dermatitis may warrant a consultation with a dermatologist, as does a suspicion of rarer nodular diseases.
Contact allergy may be established by patch testing.
A vascular surgeon should be consulted if venous insufficiency that lends itself to surgical correction is suspected.
References
Sundaresan S, Migden MR, Silapunt S. Stasis Dermatitis: Pathophysiology, Evaluation, and Management. Am J Clin Dermatol 2017;18(3):383-390. [PubMed]
Ely JW, Rosenfeld S, Seabury Stone M. Diagnosis and management of tinea infections. Am Fam Physician 2014;90(10):702-10. [PubMed]
van Zuuren EJ, Fedorowicz Z, El-Gohary M. Evidence-based topical treatments for tinea cruris and tinea corporis: a summary of a Cochrane systematic review. Br J Dermatol 2015;172(3):616-41. [PubMed]