A-Z OF SKIN

Anetoderma is a localised laxity or looseness in the skin, appearing as an outpouching or herniation of skin that is softer than the normal skin that surrounds it. It occurs due to loss of the elastic tissue in the skin.

This condition occurs more often in females than in males, and most commonly affects those between the ages of 15 to 30.

Anetodermas may be described as “primary” or “secondary” depending on how they occur. Secondary anetoderma occurs at the site of a preceding skin lesion of another cause. Primary anetoderma occurs in the skin without a preceding skin lesion.

Causes of primary and/or secondary anetoderma include:

• Infections (such as leprosy, Lyme disease, HIV)
• Inflammatory conditions (such as systemic lupus erythematosus, Sjogren’s syndrome, Graves’ disease)
• Haematologic conditions (such as anti-phospholipid syndrome)
• Medications (such as penicillamine)
• Endocrine disorders (such as Addison’s disease)

Causes of secondary anetoderma include:

• Infections (such as syphilis, varicella zoster virus or chickenpox)
• Inflammatory conditions (such as acne, lupus profundus, granuloma annulare)
• Tumours (such as pilomatrixoma, plasmacytoma, schwannoma)
• Infantile haemangiomas

The precise mechanics of how it develops is not understood.

Anetoderma is characterised by well-defined areas lacking elasticity, with the skin’s surface appearing flaccid or loose. Anetodermas can vary in colour but they are usually skin-coloured. They may occur at one site or many. They vary in size from 5 to 30 mm. Anetoderma may occur on any part of the body but most commonly occurs on the limbs, chest, back and neck.

When anetoderma is suspected a skin biopsy can help to confirm the diagnosis. Skin biopsy reveals loss of elastic fibres in the dermis (deep layer of the skin). The collagen is normal.

Investigations for associated conditions may be undertaken, if appropriate.

This condition is difficult to treat. Physical measures such as excision (surgical removal) may be practical for a few small lesions but widespread cases are challenging.

A primary cause or association, once identified, will require appropriate management in its own right.

The elastic fibres do not return over time so the lesions tend to remain unchanged.