What causes transient hypopigmentation on the skin, particularly on the forearms and arms, with a dry skin appearance?

From the Guidelines

Transient hypopigmentation on the skin, particularly on the forearms and arms with a dry appearance, is most likely caused by the use of topical corticosteroids, which can lead to skin atrophy, striae, folliculitis, telangiectasia, and purpura, as well as exacerbate conditions like acne, rosacea, and perioral dermatitis, as noted in the joint AAD-NPF guidelines of care for the management and treatment of psoriasis with topical therapy and alternative medicine modalities for psoriasis severity measures 1. To address this condition:

• Use a gentle, fragrance-free moisturizer daily, especially after bathing.
• Apply a broad-spectrum sunscreen (SPF 30 or higher) to affected areas when exposed to sunlight.
• Consider using over-the-counter 1% hydrocortisone cream for 1-2 weeks if there's mild itching or inflammation. For persistent cases, consult a dermatologist. They may prescribe:

• Topical calcineurin inhibitors like tacrolimus 0.1% ointment, applied twice daily for 2-4 weeks.
• Low-potency topical corticosteroids for short-term use. The depigmentation occurs due to a mild inflammation in the skin that affects melanocytes (pigment-producing cells). This, combined with dry skin, creates the characteristic pale, slightly scaly patches. The condition is self-limiting and usually resolves within a few months to years, but proper skin care can speed up recovery and prevent recurrence. Avoid harsh soaps, excessive sun exposure, and scratching the affected areas, as these can worsen the condition or delay healing. It's essential to note that the provided guidelines and studies also discuss other conditions like vitiligo, which can cause depigmentation, but the most recent and relevant study 1 suggests that topical corticosteroid use is a common cause of transient hypopigmentation, especially on the forearms and arms.

From the Research

Causes of Transient Hypopigmentation

• Transient hypopigmentation can be caused by various factors, including genetics, UV exposure, and certain drugs, as stated in the study 2.
• Dry skin (xerosis) can also contribute to hypopigmentation, especially on areas such as the forearms and arms, as it is associated with skin thickening and thinning, and can be triggered by exogenous and endogenous factors 3.
• Other factors such as climate, environment, lifestyle, medication, hormone fluctuations, and organ diseases can also trigger dry skin, leading to hypopigmentation 3, 4.

Relationship between Dry Skin and Hypopigmentation

• Dry skin requires a water content of 10-15% to remain supple and intact, and the predominance of hydrophobic substances in intercellular constituents regulates the humidity of the skin 3.
• Emollients can help restore damaged intercorneocyte lipid structures and increase the water content of the skin, reducing scaling and improving its barrier function, which may help alleviate hypopigmentation caused by dry skin 3.
• The use of moisturizers and anti-ageing substances can also help manage dry and photo-aged skin, which may contribute to hypopigmentation 4.

Specific Conditions related to Hypopigmentation

• Vitiligo is a depigmenting disorder characterized by the progressive loss of melanocytes, which can lead to hypopigmentation, and can be treated with depigmentation therapy or medical tattooing 5, 6.
• The choice of treatment for vitiligo depends on the extent of the condition, the patient's skin type, and the potential psychosocial implications of skin color change 5, 6.